Build a ground-level deck by establishing the finished deck elevation first, confirming how water will drain beneath it, selecting an appropriate foundation, and then designing the shallowest framing system that still satisfies structural span and decking requirements.

Do not start by buying deck blocks or choosing 2×6 joists. Low decks can be attached, freestanding, surface-supported or built over concrete, and those configurations can have very different code, foundation, ventilation and moisture requirements.

Why Ground-Level Decks Are Harder Than They Look

A raised deck has room to stack the structure vertically:

A low deck may not have enough room for that arrangement.

A nominal 2×8 joist is about 7¼ inches deep. Add roughly an inch of decking and the walking surface plus joist assembly already consumes more than 8 inches of vertical space.

That is before adding:

• a dropped beam
• post or beam hardware
• support height
• clearance beneath the joists
• drainage space
• or an exterior-door step-down

That is why ground-level decks often use:

• flush beams instead of dropped beams
• shorter joist spans
• additional support lines
• shallower joists where span tables actually permit them
• freestanding framing
• low-profile support systems
• or sleepers over an existing solid substrate

What Counts as a Ground-Level Deck?

“Ground-level deck” describes the height of a deck more than its structural system.

Two decks that both sit 12 inches above a lawn can be built very differently.

Is a Ground-Level Deck the Same as a Floating Deck?

Not exactly.

“Floating deck” usually means a deck that is freestanding rather than structurally attached to the house.

Many floating decks happen to be low, but “floating” does not mean the deck can simply rest loosely on the yard.

It still needs a complete support system and enough stability to control movement.

Why Ground-Level Deck Guides Mention 20 Inches, 30 Inches and 200 Square Feet

These numbers appear constantly in deck articles, but they do not all belong to the same rule.

Does a Ground-Level Deck Need a Permit?

Possibly.

Under the 2024 IRC model-code permit exemption, a deck must satisfy all of the applicable conditions to qualify.

The commonly cited conditions include:

• no more than 200 square feet
• no more than 30 inches above grade at any point
• not attached to a dwelling or townhouse
• not serving the required exit door

Local amendments can also change the model-code rule.

Zoning, setbacks, easements, HOA restrictions, floodplain rules and other local requirements may still apply even when a building permit does not.

Start With the Ground-Level Deck Height Budget

Before selecting joists or foundations, determine how much vertical space the structure actually has.

A deck beside a house is constrained from both directions.

Ground-Level Deck Height Planner

Use this tool to test whether the basic vertical geometry of a proposed low-deck assembly can physically fit.

Plan the Deck Height From the Door and the Ground at the Same Time

A common mistake is choosing the deck height from the exterior door and ignoring everything that has to fit underneath.

Before setting the elevation, account for:

• door and landing geometry
• decking thickness
• joist depth
• beam configuration
• foundation/support height
• manufacturer-required clearance
• site drainage
• and any required step down from the threshold

The door gives you the upper limit.

The ground and framing system give you the lower limit.

Drainage Comes Before the Foundation

Water is one of the biggest durability risks for a ground-level deck.

Low framing sits in the coolest, dampest part of the site and often receives less airflow than an elevated deck.

Water trapped beneath the structure can:

• keep treated framing wet longer
• increase connector corrosion exposure
• encourage vegetation
• create persistent mud
• contribute to frost-related soil movement
• and reduce drying beneath composite decking

Do Not Make the Ground Perfectly Level Just Because the Deck Is Level

The deck structure needs to be built level where the design requires it.

The soil underneath does not necessarily need to be.

In many cases, maintaining positive drainage beneath the deck is more important than creating a perfectly flat excavation.

Do Not Dig a Bowl Under the Deck

Excavating the entire site to gain framing clearance can create a depression that collects water.

If removing soil is necessary, plan where runoff will go before removing it.

How to Prepare the Ground Under a Ground-Level Deck

A practical preparation sequence is:

1. Find the high and low points of the site.
2. Establish the desired finished deck elevation.
3. Determine how much excavation is actually necessary.
4. Preserve or create positive drainage.
5. Remove vegetation, roots and unsuitable organic material where required.
6. Prepare bearing areas for the selected foundation system.
7. Install structural supports.
8. Finish exposed under-deck areas with gravel or vegetation-control measures if desired.

Should You Put Gravel Under a Ground-Level Deck?

Gravel can be useful, but it is not a substitute for drainage or structural support.

A properly prepared stone surface can:

• reduce mud
• limit vegetation
• create a cleaner inspection area
• make water less likely to sit directly against exposed soil surfaces

But a shallow layer of stone does not automatically:

• fix poorly draining soil
• replace required footings
• create engineered bearing
• eliminate frost movement
• or satisfy decking ventilation requirements

Should You Put Landscape Fabric Under the Deck?

Landscape fabric can help control vegetation.

Treat it as weed control—not as the foundation, drainage system or moisture barrier for the structure.

How Much Ground Clearance Does a Low Deck Need?

There is no single clearance number that applies to every composite or PVC deck.

Manufacturer instructions can differ significantly.

For the rest of the decking installation requirements, use How to Install Composite Decking.

Which Foundation Should You Use for a Ground-Level Deck?

There is no universal “ground-level deck foundation.”

Work through the decision instead.

Ground-Level Deck Foundation Options

Can You Build a Ground-Level Deck on Deck Blocks?

Sometimes.

But “the deck is low” is not enough information to answer the question.

Before using precast blocks, verify:

• the code edition adopted locally
• whether the deck is attached or freestanding
• deck area
• deck height
• soil and bearing conditions
• frost conditions
• support spacing
• and whether the proposed framing system is permitted with that support method

Should a Ground-Level Deck Be Attached or Freestanding?

A deck beside a house does not automatically need to be attached to it.

When Freestanding May Be Easier

A freestanding design can be attractive when the desired deck height creates a difficult ledger condition.

Examples include:

• masonry veneer
• awkward siding-to-foundation transitions
• cantilevered floors
• questionable existing rim framing
• limited room for a ledger
• or a desire to avoid penetrating the building envelope

How to Frame a Ground-Level Deck

Use a Flush Beam When a Dropped Beam Will Not Fit

A dropped beam sits below the joists.

A flush beam sits within the joist depth, with joists connected to the side of the beam using approved structural connections.

On a low deck, moving the beam into the joist plane can save substantial vertical space.

See the Deck Framing Layout Guide for the full framing relationship.

Shorten the Joist Span Instead of Guessing at Joist Size

Low decks have one useful structural advantage: adding another support line can often be easier than it would be on a tall deck.

Reducing the span may allow a shallower joist where the appropriate span table permits it.

Can You Use 2×6 Joists on a Ground-Level Deck?

Yes—when the applicable span table permits them.

A 2×6 is not automatically too small, and a 2×8 is not automatically required simply because the structure is a deck.

Joist capacity depends on:

• species
• grade
• spacing
• span
• loading
• cantilever
• and applicable wet-service conditions

Use the Deck Joist Span Chart to size the framing from actual span data.

Example: Why Species Matters

Under the stated loading and grading assumptions in the BYS joist-span guide, a 2×6 at the same spacing can have different allowable spans depending on the lumber species group.

Those are examples under specific assumptions—not universal 2×6 limits.

Joist Spacing Also Has to Match the Decking

Structural lumber span is only one half of the framing check.

Composite and PVC decking manufacturers also limit the spacing of the joists beneath their products.

Orientation matters too.

Diagonal decking may require closer framing than boards installed perpendicular to the joists.

Use the Deck Joist Spacing Guide before finalizing the framing.

Use the Correct Pressure-Treated Lumber Near the Ground

“Pressure treated” is not a complete exposure specification.

Treated lumber is manufactured for different environments.

AWPA identifies UC4A as a common Ground Contact, General Use category.

Ground-contact treatment is important when wood is actually used in qualifying ground-contact exposure, but low-deck durability deserves another consideration:

Read the lumber end tag and verify that the treatment is appropriate for the actual exposure.

Treat Field Cuts and Holes

Cutting, notching and drilling treated lumber can expose untreated interior wood.

Where the treatment system and applicable standards call for field treatment, apply an appropriate preservative to those exposed areas.

Use Fasteners and Connectors Compatible With Treated Lumber

Ground-level framing can expose hardware to persistent moisture.

Structural connectors and fasteners must be suitable for:

• exterior use
• the preservative treatment used in the lumber
• the expected moisture exposure
• and the specific structural connection

Do not substitute generic interior screws or hardware just because the deck is close to the ground.

Can You Build a Ground-Level Deck Over a Concrete Patio?

Often—but the correct system is usually different from a conventional deck over soil.

An existing slab can provide a solid substrate, but you still have to preserve drainage and create enough structure to support and fasten the decking correctly.

A sleeper system over dirt, loose gravel or pavers should not be assumed acceptable simply because the decking is close to the ground.

If the project involves covering an existing deck or other structure, see Composite Decking Over an Existing Deck.

Can You Build a Ground-Level Deck on Sloped Ground?

Yes, but slope can turn a “ground-level” deck into a raised deck very quickly.

Imagine the uphill side of the deck sits 10 inches above grade.

If the ground falls away another 24 inches across the deck, the downhill edge can end up more than 30 inches above grade even though the house side still looks ground level.

That can affect:

• guard requirements
• stairs
• permit analysis
• foundation height
• post requirements
• lateral stability
• and the visual proportions of the deck

Do Not Trap Water Against the House

A low deck creates a tight transition between:

• decking
• siding
• foundation
• door trim
• mulch or landscaping
• and finished grade

If the deck is attached, ledger flashing and proper structural attachment are critical.

If the deck is freestanding, maintain enough separation and drainage so the deck does not become a shelf that traps:

• wet leaves
• soil
• mulch
• snow
• or runoff

against the building.

Plan Maintenance Access Before You Cover the Framing

One major difference between a low deck and a raised deck is accessibility.

Once decking is installed over a deck only a few inches above grade, some areas underneath may become extremely difficult to inspect or repair.

Before closing the deck, identify:

• hose bibs
• foundation cleanouts
• downspouts
• drainage lines
• irrigation valves
• electrical equipment
• dryer vents
• foundation inspection areas
• and any utilities that may need future service

If something important will become inaccessible, modify the deck layout before installing the surface.

Installing Composite Decking on a Ground-Level Deck

Once framing is complete, verify the exact decking manufacturer’s rules for:

• maximum joist spacing
• diagonal installation
• side-to-side spacing
• end-to-end spacing
• clearance from fixed structures
• ventilation
• ground clearance
• approved fasteners
• and sleeper applications

Use Deck Board Spacing for the broader movement/gapping framework and How to Install Composite Decking for the full installation process.

Plan the Deck Board Layout Before Closing the Frame

A low deck still needs the same perimeter support and board-layout planning as a raised deck.

Decide early whether the deck will use:

• straight field boards
• a picture-frame border
• a breaker board
• balanced final board widths
• or fascia beneath the perimeter

Use the Deck Board Layout Planner before framing support for the surface.

Picture Framing a Ground-Level Deck

Picture framing works especially well on a low deck because the perimeter is visually prominent from the yard.

But the border changes the framing.

Plan:

• perimeter blocking
• support beneath border boards
• decking orientation
• approved overhang
• fastener access
• and fascia position

See How to Picture Frame a Deck.

Fascia Can Reduce Airflow Around a Ground-Level Deck

Fascia gives the deck a finished appearance, but enclosing the edge can also reduce natural airflow.

Do not hide the framing at the expense of manufacturer-required ventilation or drainage.

The fascia fastener pattern, gaps, spacers and finished-edge relationship should follow the exact fascia system being installed.

See How to Install Deck Fascia.

Does a Ground-Level Deck Need a Railing?

Many low decks do not require guards.

Under current IRC model provisions, the familiar guard threshold generally applies where an open-sided walking surface is more than 30 inches above the floor or grade below at any point within 36 inches horizontally from the edge.

That means a sloped yard can matter.

A deck that sits only 14 inches above grade at the house may still exceed the guard threshold at the downhill edge.

Does a Ground-Level Deck Need Steps?

Very low decks may transition directly to a walkway, patio or lawn.

Once the elevation increases, do not solve the difference with one awkward, oversized step.

If stairs are required, use Deck Stairs Guide and Deck Stair Stringer Spacing.

Locate Underground Utilities Before Digging

Ground-level does not mean digging-free.

Footings, piles, grading, drainage work and even shallow support preparation can disturb buried utilities.

In the United States, contact 811 before excavating.

Visit 811 Before You Dig →

How to Build a Ground-Level Deck: Step-by-Step Planning Sequence

1. Check permits, zoning and local deck requirements.
2. Locate underground utilities.
3. Survey the ground elevation across the entire deck area.
4. Choose the finished deck height.
5. Determine whether the deck will be attached or freestanding.
6. Verify the decking manufacturer’s minimum clearance and ventilation requirements.
7. Check whether the proposed framing physically fits in the available height.
8. Correct drainage and site grading.
9. Select the foundation/support system.
10. Lay out supports, beams and joist spans.
11. Size joists and beams from actual span requirements.
12. Install the foundations or approved support system.
13. Build and square the structural frame.
14. Add picture-frame, breaker-board or perimeter blocking.
15. Protect framing where appropriate and treat qualifying field cuts.
16. Verify drainage and service access before installing decking.
17. Install deck boards using the exact manufacturer spacing and fastener rules.
18. Install fascia without blocking required airflow.
19. Add stairs or guards where required.

15 Ground-Level Deck Mistakes to Avoid

Why Ground-Level Decks Fail Early

Ground-Level Deck FAQ

How high is a ground-level deck?

There is no universal code definition of “ground-level deck.” The phrase usually describes a low deck built close to grade, but different code provisions use different height thresholds.

Can I build a deck directly on the ground?

Certain low freestanding configurations may permit very shallow support systems under applicable local rules, but direct or near-grade framing is not automatically appropriate.

Drainage, wood treatment, ventilation, structural support and product requirements still apply.

Can I use deck blocks?

Possibly. Whether deck blocks are acceptable depends on the adopted local code, attachment condition, height, area, soil, frost conditions and structural design.

Do ground-level decks need frost-depth footings?

Some do. Certain freestanding low-deck conditions may qualify for different footing provisions, but attached decks and other configurations can still require conventional frost-protected support.

Can I use 2×6 joists?

Yes where the 2×6 joists satisfy the applicable span table for the actual species, grade, spacing, loading and support configuration.

How much clearance should be under a ground-level deck?

There is no universal number. Current manufacturer instructions vary, particularly for composite and PVC decking.

Should I put gravel underneath?

Gravel can reduce mud and vegetation and create a cleaner under-deck surface, but it does not replace positive drainage or required structural supports.

Can I build a deck over concrete?

Often yes, using a compatible sleeper or pedestal system. Follow the exact decking manufacturer’s instructions for sleeper dimensions, drainage, airflow and fastening.

Can a ground-level deck be built on a slope?

Yes, but the downhill edge may end up much higher above grade than the uphill side. That can change guards, stairs, foundations and permit requirements.

Does a ground-level deck need a railing?

Many do not. Under current IRC model provisions, guards generally become required where the open-sided walking surface exceeds the applicable 30-inch condition measured to the grade below within 36 inches horizontally of the edge.

Should the deck be attached to the house?

Not automatically. An attached deck can make sense where a proper ledger condition exists. A freestanding deck may be preferable where attachment, flashing or available height would be problematic.

Can composite decking be installed close to the ground?

Often yes, but only when the exact product’s ground-clearance, ventilation, framing and drainage requirements are met.

Ground-Level Deck Technical Sources

Codes and manufacturer installation instructions can change. Verify the code edition adopted locally and the latest instructions for the exact product being installed.

• International Code Council — International Residential Code
  Browse ICC code resources →
• American Wood Council
  Browse AWC deck and wood-framing resources →
• American Wood Protection Association
  AWPA treated-wood guidance →
• TimberTech
  TimberTech FAQs and installation guidance →
• Fiberon
  Fiberon installation and ventilation FAQs →
• Deckorators
  Deckorators installation instructions →
• 811
  811 Before You Dig →

Last reviewed: September 2026

The Backyard Standard Final Answer

A ground-level deck is not simply a normal deck with shorter posts.

Building close to the ground changes the design problem.

You have less room for beams and joists, less natural airflow, greater moisture exposure, tighter drainage constraints and fewer ways to correct an elevation mistake once construction begins.

Start with the finished deck elevation and the site’s drainage.

Then decide whether the deck should be attached or freestanding and choose a foundation appropriate for the code, soil, frost conditions and structural design.

Size the framing from actual spans instead of choosing the shallowest lumber that fits.

Finally, verify that the decking, treated lumber, connectors, fasteners, sleepers and finish materials are approved for the clearance and exposure created by the design.

How to Build a Freestanding Deck: Quick Answer

A freestanding deck is structurally independent of the house.

A conventional rectangular freestanding deck beside a house often uses:

joists → house-side beam + outside beam → posts → foundations

Going freestanding eliminates the structural ledger, but it does not eliminate:

• footings or another approved foundation system,
• beam sizing,
• post sizing,
• post-to-foundation connections,
• beam-to-post connections,
• uplift resistance, or
• lateral stability.

Freestanding vs Floating vs Ground-Level Deck

These terms are frequently mixed together online, but they describe different things.

See How a Freestanding Deck Supports Itself

The easiest way to understand a freestanding deck is to compare its structure with an attached deck. The difference is what supports the house side of the joists.

When Is a Freestanding Deck Better Than an Attached Deck?

The strongest reason to choose freestanding construction is usually that the house does not provide a simple, verifiable ledger connection.

Brick or Stone Veneer

Masonry veneer should not simply be treated as the structural support for a deck.

Depending on the house and approved connection, options may include:

• an approved connection through the veneer into structural framing, or
• a completely independent freestanding deck.

Cantilevered Floors & Bump-Outs

A house bump-out or cantilever can create a difficult ledger condition because the visible rim area may not have the support required for an ordinary prescriptive attachment.

Complex Exterior Wall Systems

Freestanding construction may also be worth considering with:

• thick exterior insulation,
• EIFS,
• certain stucco assemblies,
• ICF construction,
• unusual floor framing, or
• wall assemblies that make ordinary ledger flashing or attachment difficult.

Unknown Existing Framing

Older homes may hide:

• damaged rim framing,
• rot,
• unusual repairs,
• multiple siding layers, or
• framing that cannot be verified without opening the wall.

Attached vs Freestanding Deck: What Changes?

How to Build a Freestanding Deck Next to a House

Keep the Structural Load Paths Independent

Do not drive a few structural screws through the deck rim into the house simply because the frame feels easier to stabilize that way.

If a connection to the house participates structurally, it should be part of the intentional approved design.

Leave an Intentional Drainage Detail

There is no single national rule requiring every freestanding deck to sit exactly 1 inch, 2 inches or another universal distance from the house.

Coordinate separation with:

• the wall assembly,
• decking requirements,
• drainage,
• movement of the structures, and
• local construction requirements.

Coordinate the Exterior Door

Structural independence does not remove exterior-door landing and threshold requirements.

Establish the finished deck elevation before finalizing:

• joist depth,
• beam elevation,
• post height,
• foundation height, and
• drainage beside the house.

Freestanding Deck Code: 20 Inches, 30 Inches & 200 Square Feet

These numbers are often blended into one supposed “floating deck rule.” They actually belong to different code provisions.

What the 20-Inch Pier-Block Exception Actually Describes

Current model-code provisions include a narrow exception for certain very low freestanding decks.

The applicable conditions include:

• freestanding construction,
• the applicable 200-square-foot limit,
• the applicable 20-inch walking-surface height condition, and
• joists supported directly on qualifying precast concrete pier blocks at grade.

Does a Freestanding Deck Need a Permit?

Possibly.

Under the model IRC permit exemption, the commonly cited conditions include:

• no more than 200 square feet,
• no more than 30 inches above grade at any point,
• not attached to the dwelling or townhouse, and
• not serving the required exit door.

For broader permit planning, see the Deck Permit Cost Guide.

Call 811 Before Digging Deck Footings

Freestanding decks commonly require more excavation than attached decks because they often add another full row of supports.

Before digging for:

• footings,
• piers,
• helical piles,
• drainage work, or
• grading,

arrange underground utility locating.

Visit 811 Before You Dig →

Freestanding Deck Foundation Options

How Deep Do Freestanding Deck Footings Need to Be?

Step 1: Check Whether a Specific Exception Applies

Certain very low freestanding deck configurations can qualify for model-code foundation exceptions.

If every condition is not met, continue to the ordinary footing rules.

Step 2: Ordinary Deck Footings Have a Minimum Depth

Under the model IRC deck provisions, ordinary deck footings that do not qualify for an exception are generally required to extend at least 12 inches below undisturbed ground surface.

Step 3: Frost Requirements May Require More

Required depth can increase based on:

• the adopted code,
• local amendments,
• attachment condition,
• foundation system,
• soil conditions, and
• local frost depth.

The House-Side Footing Problem Most Freestanding Deck Guides Miss

Eliminating the ledger normally means adding another support row close to the house.

That is convenient structurally—but the soil there can be problematic.

The Soil Beside the House May Be Foundation Backfill

House foundations are excavated and then backfilled after construction. That soil may not provide the same bearing conditions as undisturbed natural soil.

Pay particular attention around:

• basements,
• deep crawlspaces,
• recent construction,
• poorly compacted fill, and
• areas softened by drainage problems.

The design goal is suitable bearing that satisfies the applicable foundation requirements—not simply putting a footing wherever the beam happens to land.

Design a Freestanding Deck in the Right Order

Post spacing should not be the first framing decision.

1. Size the Joists

Joist span depends on:

• species,
• grade,
• joist size,
• spacing,
• load,
• wet-service conditions, and
• cantilever conditions.

Use the Deck Joist Span Chart and Deck Joist Spacing Guide.

2. Size the Beams

Beam capacity depends on the load delivered by the joists.

Use the Deck Beam Span Chart after establishing the actual joist span and beam layout.

3. Choose Post Spacing

Post spacing follows the allowable beam span—not a convenient round number.

4. Size the Posts

Post size depends on factors including:

• species,
• post height,
• tributary area, and
• design load.

Use the Deck Post Size Chart: 4×4 vs 6×6.

Beam Bearing & Beam-to-Post Connections

Beam strength does not help if the load is not transferred properly into the posts below.

Prescriptive deck framing provisions generally require beam ends to have:

• at least 1½ inches of bearing on wood or metal, or
• at least 3 inches on concrete or masonry.

At intermediate supports beneath a multi-ply beam, the required plies need full bearing at the support.

What Does Each Freestanding Deck Footing Actually Carry?

Each post and footing carries a portion of the deck called its tributary area.

This explains why:

• interior posts can carry more load than corner posts,
• wider post spacing increases footing reaction,
• longer joist spans can increase beam load, and
• identical-looking footings do not always carry identical loads.

Use the Deck Footing Calculator once the framing layout is established.

Post-to-Footing Connections

A post simply resting on concrete is not automatically a complete structural connection.

Where posts bear on concrete, the applicable design needs appropriate lateral restraint through:

• an approved post base or connector,
• a permitted embedded-post detail, or
• another approved foundation system.

Lateral Stability Is the Critical Freestanding-Deck Difference

An attached deck receives restraint from its structural relationship to the house.

A freestanding deck must control movement independently.

That includes:

• side-to-side sway,
• front-to-back movement,
• racking,
• applicable wind effects, and
• other lateral loads required by the design.

Does a Freestanding Deck Need Diagonal Bracing?

Many elevated freestanding decks need a deliberate lateral-resistance strategy.

Diagonal braces can be part of that strategy, but there is no responsible national rule that says:

“Put the same knee brace on every post.”

Bounce vs Sway: Diagnose the Right Problem

Stop and Redesign the Load Path for Heavy or Wind-Loaded Features

When Does a Freestanding Deck Deserve Engineering?

There is no universal national height at which every freestanding deck automatically requires engineering.

Project-specific engineering or AHJ review becomes especially valuable with:

• tall posts,
• significant sway or lateral-demand concerns,
• unusual geometry,
• large cantilevers,
• questionable soils,
• deep foundation backfill,
• nearby retaining walls,
• high wind, snow or seismic loads,
• pergolas or roofs,
• hot tubs,
• large privacy walls, or
• connections outside prescriptive details.

Low Freestanding Decks Need a Different Planning Approach

When a freestanding deck sits close to grade, the dominant problem becomes fitting:

• supports,
• beams,
• joists,
• decking,
• drainage, and
• manufacturer-required airflow

into very little vertical space.

Use How to Build a Ground-Level Deck for that design problem.

Freestanding Decks on Sloped Ground

As the ground falls away:

• post height increases,
• lateral stability becomes more important,
• footing conditions change,
• stairs may become necessary, and
• guard requirements can appear.

Drainage Still Matters

Avoid trapping water:

• beneath the deck,
• against the house,
• around posts,
• around foundations, and
• on horizontal framing surfaces.

Useful Products for Freestanding Deck Foundations & Framing

These products solve different parts of a freestanding deck build. Structural hardware must be selected for the exact member sizes, substrate, loads, corrosion exposure and approved connection detail.

As an Amazon Associate, The Backyard Standard may earn from qualifying purchases.

See the Deck Building Tools Guide for additional layout, drilling and framing tools.

Composite Decking on a Freestanding Deck

A structurally correct freestanding frame still has to satisfy the decking manufacturer’s installation requirements.

Verify:

• joist spacing,
• diagonal-installation limits,
• board spacing,
• ground clearance,
• ventilation,
• blocking,
• approved fasteners, and
• perimeter support.

Continue with How to Install Composite Decking and Deck Board Spacing.

Plan the Deck Board Layout Before Framing Is Finished

Decide whether the deck will use:

• straight field boards,
• picture framing,
• a breaker board,
• a double border, or
• balanced final board widths.

Those choices change the blocking and perimeter framing.

Use the Deck Board Layout Planner before closing the frame.

If you are adding a border, see How to Picture Frame a Deck.

Guards & Stairs on a Freestanding Deck

Does a Freestanding Deck Need a Railing?

Guard requirements depend primarily on walking-surface height above the floor or grade below—not whether the deck is freestanding.

Under current model-code provisions, the familiar guard trigger generally applies where the open-sided walking surface is more than 30 inches above the grade or floor below at a point within 36 inches horizontally from the edge.

For railing layout, see the Deck Railing Post Spacing Guide.

Freestanding Deck Stairs

Stairs need their own:

• upper attachment,
• stringer support,
• lower landing/support,
• tread/riser geometry, and
• guard/handrail details where required.

Use the Deck Stairs Guide and Deck Stair Stringer Spacing Guide.

How to Build a Freestanding Deck: Correct Planning Sequence

1. Check permits, zoning, setbacks and site restrictions.
2. Contact 811 before excavation.
3. Confirm that the deck will remain structurally independent of the house.
4. Set the finished deck elevation and door relationship.
5. Survey grade and establish drainage.
6. Choose the deck dimensions and joist direction.
7. Determine joist span.
8. Establish the beam locations.
9. Size the beams from the joist load.
10. Determine post spacing from the beam design.
11. Determine tributary loads at each post and footing.
12. Check post size and structural height limits.
13. Evaluate soil bearing, foundation backfill and frost requirements.
14. Select the foundation system.
15. Install footings or approved foundations.
16. Install post bases / anchorage and posts.
17. Install beams with proper bearing and approved connections.
18. Install and square the joist frame.
19. Install required lateral and uplift resistance.
20. Add blocking for borders, guards, stairs and concentrated loads.
21. Complete moisture protection and qualifying field-cut treatment.
22. Verify drainage and house separation.
23. Install decking according to manufacturer requirements.
24. Complete fascia, stairs and guards.

18 Freestanding Deck Mistakes to Avoid

Freestanding Deck FAQ

What is a freestanding deck?

A freestanding deck supports itself independently instead of relying on a structural ledger connection to the house.

Is a freestanding deck the same as a floating deck?

No. Floating deck is an informal term usually applied to a low freestanding platform. Freestanding is the broader structural category.

Does a freestanding deck need footings?

Many do. Limited exceptions exist for certain low freestanding configurations, but conventional and elevated freestanding decks commonly require structural foundations.

How deep do freestanding deck footings need to be?

First determine whether a specific foundation exception applies. If not, model-code deck provisions generally establish at least 12 inches below undisturbed ground surface before deeper frost or local requirements are considered.

Can a freestanding deck sit on deck blocks?

Certain qualifying low freestanding configurations may use precast pier blocks where the adopted code permits. Freestanding status alone does not make surface blocks acceptable.

Does a freestanding deck need frost-depth footings?

Not every freestanding deck receives the same answer. Check the adopted local code, soil conditions, foundation system and frost requirements.

Does a freestanding deck need two beams?

A conventional rectangular freestanding deck beside a house commonly uses two primary beam lines, but other approved layouts are possible.

Can a freestanding deck use 4×4 posts?

Some qualifying configurations can. Post size depends on species, structural height, tributary area and load, not simply whether the deck is freestanding.

How close can a freestanding deck be to a house?

There is no universal national spacing number. Coordinate the wall assembly, drainage, decking system, structure movement and local requirements.

Can I screw a freestanding deck to the house for stability?

Not casually. If the house connection becomes part of the structural load path, it should be intentionally designed rather than added as an anti-wobble fix.

Does a freestanding deck need diagonal bracing?

Elevated freestanding decks commonly need deliberate lateral resistance, but the correct brace or stability system depends on the actual deck geometry, posts, foundations and connections.

Can I put a pergola on a freestanding deck?

Yes if the deck, posts and foundations are designed for the additional gravity, wind, uplift and lateral loads.

Sources & Technical References

Last reviewed: September 2026

• International Code Council — International Residential Code — Residential deck footing, framing, guard and permit provisions.
• American Wood Council — DCA6 — Residential deck framing concepts and prescriptive guidance within its stated scope.
• American Wood Council — Technical FAQs — Beam bearing, post connections, bracing and deck-framing guidance.
• American Wood Protection Association — Treated wood exposure and field-treatment guidance.
• Simpson Strong-Tie — Deck Connection & Fastening Guide — Footings, post bases, beam-to-post, joist and other structural deck connections.
• Simpson Strong-Tie — Brick Veneer Deck Attachment — Masonry-veneer attachment issues and freestanding alternatives.
• 811 Before You Dig — National underground utility locating resource.

The Backyard Standard Final Answer

What Is a Deck Beam Splice?

A deck beam carries loads from the joists and transfers those loads into the posts and footings below.

If one continuous piece of lumber cannot extend for the full required beam length, the beam may need to be assembled from multiple pieces. The location where one beam section terminates and another begins is a beam splice.

With a built-up beam, there are actually two related but different issues:

1. Beam splice: Where an individual beam ply ends and another section begins.
2. Beam assembly: How the individual plies of a double or triple beam are fastened together to form the built-up beam.

Those should not be confused.

Fastening the plies together correctly is important, but the fasteners joining the beam assembly do not eliminate the need for proper support at a splice.

Where Can You Splice a Deck Beam?

For the common prescriptive built-up deck-beam configurations covered by residential deck provisions, the safe starting point is simple:

Locate the beam splice at a prescribed support.

AWC DCA 6 explicitly states that splices of multi-span beams are located at interior post locations. The IRC deck provisions require full bearing of each ply where multiple-span beams bear on intermediate posts and govern the associated post-to-beam connection. Use the requirements of the code edition actually adopted for the project.

This is fundamentally different from taking two beam sections that end somewhere between posts, butting their ends together, and trying to create continuity with bolts or screws.

That last distinction matters. Saying that an unsupported beam splice is not part of the ordinary prescriptive detail is not the same as saying that no engineered beam splice can ever exist away from a post.

Engineered wood products, steel plates, proprietary connectors or specifically designed connections can create conditions outside the basic prescriptive deck details.

But that is a design problem—not a reason to improvise an unsupported joint on site.

Why a Deck Beam Splice Belongs at a Support

To understand why splice location matters, follow the deck’s load path.

The decking transfers load to the joists. The joists transfer load to the beam. The beam transfers load into the posts, which transfer it through the post bases and footings to the soil.

In simplified form:

DECKING → JOISTS → BEAM → POST → FOOTING → SOIL

At a supported beam splice, the end reaction from each applicable beam section can transfer through bearing into the post or approved connection below.

Move that same butt joint into the span between posts and the structural problem changes.

The connection now has to transfer forces across a location where the beam itself is carrying bending and shear. Simply pulling the two ends together does not make two pieces of dimensional lumber behave automatically like one continuous unspliced member.

Beam Bearing Is the Critical Detail

Putting a splice “over a post” is only the beginning. Under IRC deck-beam provisions, beam ends require at least 1-1/2 inches of bearing on wood or metal and 3 inches on concrete or masonry for the full beam width. Where a multiple-span built-up beam bears on an intermediate post, each ply must have full bearing on the post in accordance with the applicable post-to-beam detail.

That language is more useful than reducing the rule to a single “splice bearing” dimension. The actual geometry depends on which plies terminate, which continue across the support, the post size, and the approved connection detail.

Why Post Width Matters

A nominal 4×4 is approximately 3-1/2 inches wide and a nominal 6×6 approximately 5-1/2 inches wide after surfacing. Those dimensions affect whether the complete beam assembly can achieve the required bearing and connection geometry.

Deck Beam Splice: Supported vs. Unsupported

The structural distinction is easier to see than to memorize:

Can You Splice a Deck Beam Between Posts?

Do not treat an unsupported butt splice between posts as equivalent to the ordinary prescriptive deck-beam splice.

Bolting two beam ends together does not create bearing below the joint. Adding screws does not create bearing. Adding a short scab beside the joint does not automatically create a connection capable of transferring the forces carried by a continuous beam.

A splice away from the prescribed support location requires a connection designed for the forces at that location.

For a typical prescriptive residential deck, the simpler solution is usually to plan beam lengths so the splice occurs at an appropriate support.

If site conditions make that impossible, the solution should come from an applicable engineered design rather than an improvised fastener pattern.

Bolts Do Not Substitute for Bearing

This is one of the most important principles in deck framing.

A bolt can resist specific connection forces when it is part of a properly designed connection. What it does not do automatically is replace the direct wood-to-wood or connector-supported bearing required by a prescriptive beam detail.

That is why simply bolting a beam to the side of a post should not be assumed equivalent to supporting the beam on top of the post or using an approved post-to-beam connector.

The same principle applies at a beam splice.

If the structural detail relies on bearing, adding more bolts does not eliminate that requirement.

See our deck post-to-beam connection guide for the full explanation of bearing, post caps, notched posts and side-connected beam conditions.

Double-Beam Splice Details

A double deck beam is commonly assembled from two dimensional-lumber plies fastened together according to an applicable fastening schedule.

When one or more of those plies must end, the splice arrangement has to satisfy two different requirements:

1. The beam sections must have the required support and bearing.
2. The individual plies must be connected together as the required built-up beam assembly.

Do not confuse the nails or screws used to assemble the plies with a structural splice connection capable of replacing support below the beam.

Do Both Plies Have to End at the Same Location?

This is where online advice becomes inconsistent.

General AWC built-up-beam guidance recommends locating end joints over supports and offsetting end joints in adjacent plies. Deck-specific prescriptive details still control the actual project, so staggering should be treated as a useful assembly principle—not permission to violate the required support, bearing, or connection geometry.

But “always stagger every beam splice” is not an adequate substitute for the actual prescriptive requirements.

The controlling questions are whether each ply is properly supported, whether the required bearing is provided, whether the beam assembly follows the applicable fastening requirements, and whether the post-to-beam connection works with that arrangement.

Triple-Beam Splices Need Even More Planning

A triple beam adds another ply, another set of beam-end conditions and additional connection geometry.

This is where the phrase “just splice it over the post” becomes especially inadequate.

Before laying out a triple-beam splice, verify:

• the required beam size and number of plies
• the actual width of the built-up beam
• the required bearing for each applicable beam end
• the actual post dimensions
• the post-to-beam connection detail
• the required beam-ply fastening schedule
• whether the selected post cap is approved for the exact post and beam geometry

A triple 2x beam is approximately 4-1/2 inches wide. A nominal 6×6 post is approximately 5-1/2 inches wide.

Those dimensions help explain the geometry, but they do not by themselves prove that a proposed splice detail is acceptable.

The applicable prescriptive figure, approved connector detail or engineered design still controls.

If you are still determining how large the beam needs to be, use the deck beam size chart, deck beam span chart, or deck beam calculator before designing the splice.

How to Fasten Built-Up Deck Beam Plies Together

After the support and splice locations are correct, the individual beam plies still need to be assembled properly.

The 2021 IRC deck provisions require built-up beam plies to be fastened with two rows of minimum 10d (3-inch × 0.128-inch) nails at 16 inches on center along each edge. AWC DCA 6 also illustrates a prescriptive built-up beam fastening detail. Local amendments, engineered plans, or an approved alternate fastening system can change the required assembly, so use the schedule that actually governs the project.

The important point is that beam-ply fastening is not arbitrary.

More fasteners are not automatically better, and generic deck screws should not be substituted for structural fasteners simply because they are convenient.

Before Fastening a Built-Up Beam, Verify:

• required fastener type
• fastener diameter
• fastener length
• fastener spacing
• edge and end distances
• additional requirements at beam or splice ends
• corrosion resistance for the pressure-treated lumber and exposure

Our deck screws vs. structural screws guide explains the differences between decking screws, structural screws and connector fasteners.

Should Deck Beam Splices Be Staggered?

Staggering built-up beam joints is commonly recommended in deck-building guidance, but the answer needs more precision than a universal yes or no.

A staggered arrangement means adjacent beam plies do not terminate at the same support. One ply may continue across the post while another ply ends and begins there.

This can have practical advantages when the layout allows it, including maintaining continuity in part of the built-up assembly and avoiding a single joint line through every ply.

However, staggering does not eliminate the requirements that control the beam.

Each splice still needs the support and bearing required by the applicable detail. The plies still need to be assembled correctly. And the post-to-beam connection still needs to accommodate the actual beam geometry.

Post Cap vs. Notched Post at a Beam Splice

Once the splice is located at the correct support, the next question is how the beam is connected to the post.

Two common prescriptive concepts are:

• beam bearing on top of the post with an approved post cap
• beam bearing in an applicable notched-post detail

These are not interchangeable details, and neither should be selected simply because it looks convenient in the field.

The beam width, number of plies, actual post dimensions, splice location and connector geometry all matter.

Post Caps

An approved post cap can provide a defined connection between the beam and post while allowing the beam to bear at the support.

But post caps are highly specific.

A connector designed for one nominal post size, beam width or beam configuration should not be assumed to fit another.

Before using a post cap at a splice, verify:

• the exact post size
• the exact beam width
• whether the beam is single, double or triple ply
• whether the connector permits the intended splice configuration
• the approved fasteners
• the required corrosion resistance
• the connector manufacturer’s installation detail

Notched Posts

Prescriptive deck provisions also include notched-post details in certain configurations.

A notch can create direct bearing for the beam while the remaining post section and specified fasteners help restrain the connection.

But notching removes wood from the post, so the allowed geometry matters.

Wider built-up beams, different post sizes, unusual splice arrangements or configurations outside the applicable prescriptive figure should not be improvised.

See our deck post-to-beam connection guide for the full comparison of notched posts, post caps and other connection conditions.

Flush-Beam Splices Are a Different Structural Detail

Most of the discussion in this guide applies to a dropped beam supported by posts below the joists.

A flush beam is different.

In a flush-beam layout, joists typically frame into the side of the beam rather than bearing on top of it. That changes the connector geometry and load transfer.

Do not take a dropped-beam splice detail and apply it automatically to a flush beam.

A flush beam may rely on hangers and other connections that must transfer reactions into the beam differently, and the beam itself still requires adequate support at posts or other structural supports.

If you are still deciding how the beam fits into the deck structure, start with the deck framing layout guide.

Deck Beam Splice vs. Deck Beam Cantilever

A beam splice and a beam cantilever are two different structural conditions.

A splice occurs where one beam section ends and another begins.

A cantilever occurs where a continuous beam extends beyond its outer support.

Do not create what looks like a cantilever by ending one beam section beyond a post and attaching another piece to it.

A cantilever depends on continuity and the structural behavior of the beam across the support. A butt splice beyond the support is a different condition.

See our deck cantilever guide for allowable joist and beam overhang concepts.

Worked Example: Double Beam Splice Over a Post

Consider a deck using a built-up double beam that is longer than the available lumber.

The wrong way to approach the problem is:

“My boards are too short. Where can I screw another one onto the end?”

The correct process is:

1. Establish the post locations. The beam span and post spacing must already work structurally.
2. Plan the beam lengths. Arrange the lumber so required splice locations occur at appropriate supports.
3. Verify bearing. Confirm that the applicable beam ends or plies receive the required bearing at the support.
4. Verify the post-to-beam connection. Use an applicable cap, notch or other approved detail.
5. Fasten the beam plies. Follow the required built-up beam fastening schedule.
6. Protect field cuts. Treat exposed cuts where required for the pressure-treated lumber being used.

Worked Example: Triple Beam on a 6×6 Post

A nominal triple 2x beam is approximately 4-1/2 inches wide.

A nominal 6×6 post is approximately 5-1/2 inches wide.

Those dimensions may make the assembly look simple at first glance, but a splice introduces additional bearing requirements that must be checked against the applicable detail.

Do not reason:

“The beam is narrower than the post, so the splice fits.”

Instead ask:

• Where does each beam ply terminate?
• What bearing does each applicable beam end receive?
• Does the chosen post cap or notch detail accommodate that geometry?
• Does every ply have the required support?
• Does the built-up beam fastening schedule remain valid at the splice?

If the answer cannot be demonstrated from the applicable prescriptive detail or approved connector documentation, the proposed splice should not be treated as automatically acceptable.

Common Deck Beam Splice Mistakes

1. Splicing Between Posts

An unsupported butt joint between posts is not the ordinary prescriptive splice condition.

Adding bolts, screws or a short scab does not automatically create the structural continuity that the beam lost when it was cut.

2. Assuming “Over the Post” Is Enough

A splice can be located over a post and still have poor bearing geometry.

Verify the applicable bearing requirement and actual post dimensions.

3. Using a 4×4 Without Checking the Splice Detail

A nominal 4×4 is only about 3-1/2 inches wide.

Do not assume that because a beam can physically sit on the post, the same post automatically accommodates a beam splice.

4. Treating Ply Fasteners as Splice Fasteners

Nails or screws joining built-up beam plies perform a different job from a structural connection designed to transfer forces across an unsupported joint.

5. Buying the Post Cap Before Designing the Connection

The connector should follow the beam and post geometry—not the other way around.

Choose the exact connector only after the beam size, number of plies, post size and splice arrangement are known.

6. Using Deck Screws for Structural Beam Assembly

Generic decking screws are not substitutes for required structural fasteners or connector fasteners.

Use the fastener type and schedule required by the applicable design or approved fastening system.

7. Ignoring Corrosion Resistance

Beam fasteners and post-to-beam connectors are exposed to exterior moisture and often contact pressure-treated lumber.

Use hardware with the corrosion resistance required for the treatment and exposure condition.

8. Leaving Fresh Pressure-Treated Cuts Untreated

Field cuts and notches may expose wood beneath the originally treated surface.

Follow the treated-lumber and preservative guidance for field treatment where required.

For top-of-framing moisture protection after the structural details are correct, see the Deck Joist Tape & Framing Protection Guide. Follow the treated-lumber manufacturer or preservative standard for field-cut treatment itself.

How to Plan a Beam Splice Before You Cut Lumber

The easiest beam splice to build correctly is the one planned before framing begins.

1. Determine beam size. Use the applicable span table, approved design or engineered calculation.
2. Determine post spacing. Beam capacity and tributary loading control how far apart the supports can be.
3. Mark every support location. Do this before ordering or cutting beam lumber.
4. Compare available lumber lengths. Arrange beam sections so planned joints occur at appropriate supports.
5. Check splice bearing. Confirm the actual support geometry satisfies the applicable detail.
6. Select the post-to-beam connection. Match the connector or notch detail to the beam and post.
7. Lay out beam-ply fasteners. Do not invent the fastening schedule after the beam is already assembled.
8. Protect the completed framing. Field-treat cuts where required and apply framing protection where appropriate.

Deck Beam Splice Inspection Checklist

Before the joists and decking hide the connection, check:

• ☐ Beam size matches the applicable design.
• ☐ Post spacing is within the applicable beam-span limit.
• ☐ Beam splice is located at an approved or designed support condition.
• ☐ Required bearing is provided at the splice.
• ☐ Actual post dimensions are adequate for the detail.
• ☐ Every built-up beam ply has the required support.
• ☐ Post cap or notch detail matches the actual beam and post geometry.
• ☐ Connector fasteners are the specified type and size.
• ☐ Built-up beam plies follow the required fastening schedule.
• ☐ Fasteners and connectors have appropriate corrosion resistance.
• ☐ Field cuts are treated where required.
• ☐ No unsupported butt joint is being treated as a prescriptive splice.

When a Deck Beam Splice Needs Engineering

The prescriptive path works because the framing fits within a defined set of assumptions and details.

Once the proposed splice moves outside those conditions, engineering may be required.

Examples can include:

• an unsupported splice between posts
• a splice that does not provide the prescribed bearing
• unusual multi-ply arrangements
• custom steel side plates or splice plates
• proprietary engineered wood beams
• loads outside the assumptions of the prescriptive deck tables
• unusual post-to-beam geometry
• large concentrated loads
• conditions not covered by the adopted residential code or approved deck guide

Frequently Asked Questions

Can you splice a deck beam?

Yes. Built-up deck beams can use multiple lumber sections, but the splice location, bearing, beam assembly and post-to-beam connection must follow an applicable prescriptive or engineered detail.

Where should a deck beam splice be located?

For the common prescriptive built-up beam conditions covered in this guide, plan beam splices at the applicable post supports. Do not assume an unsupported butt joint between posts is equivalent.

Can I splice a deck beam between posts?

Not as the ordinary prescriptive butt-splice detail. A splice between supports must transfer structural forces across the joint and requires a connection designed for that condition.

Can I just bolt two deck beams together?

Bolts can be part of a designed connection, but bolts do not automatically replace required bearing or turn an unsupported butt joint into a continuous beam.

Do beam splices have to be over a post?

Prescriptive built-up deck-beam guidance commonly locates splices at interior post supports. Other splice locations may be possible when specifically designed, but they should not be assumed to follow the basic prescriptive detail.

Should deck beam splices be staggered?

Staggering joints between built-up beam plies can be a useful construction practice in some layouts, but it is not a substitute for required support, bearing, fastening and connection details. Do not apply “always stagger” as a universal rule.

Can both plies of a double beam splice over the same post?

Only when the resulting arrangement satisfies the applicable bearing, continuity, support, fastening, and post-to-beam connection requirements. For an IRC multiple-span built-up beam at an intermediate post, each ply must have full bearing on that post; do not judge the detail only by whether two butt joints physically fit above the support.

Can you splice a triple deck beam on a 6×6 post?

A nominal 6×6 is approximately 5-1/2 inches wide, while a triple 2x beam is approximately 4-1/2 inches wide. Those dimensions alone do not establish that a proposed splice is acceptable. Verify the specific bearing and connection detail.

Can a beam splice occur at the end post?

End-support geometry differs from an intermediate multiple-span splice. Use the applicable beam-support detail rather than assuming that an interior-post splice arrangement transfers directly to an end post.

Can structural screws replace nails in a built-up beam?

Only when the structural screw system is approved for that application and installed according to its required spacing, length, edge-distance and other specifications. Do not substitute screws into a prescriptive fastening schedule without support for that substitution.

Is a beam splice the same as a cantilever?

No. A splice joins beam sections. A cantilever is a continuous beam extending beyond a support. The structural behavior and design requirements are different.

The Bottom Line

A deck beam splice is primarily a support and bearing problem, not a fastener problem.

For common prescriptive built-up deck beams, plan splice locations around the structural supports. Verify that the beam plies receive the required bearing, that the post is large enough for the actual geometry, and that the post-to-beam connection is approved for the configuration being built.

Then assemble the built-up beam using the required fastening schedule.

Do not rely on bolts, screws, side plates or short scabs to make an unsupported butt joint equivalent to a continuous beam unless that connection has actually been designed for the forces involved.

Support first. Bearing second. Connection third.

That sequence keeps the load path clear and prevents one of the most common mistakes in DIY deck framing: trying to solve a missing support with more hardware.

Related Deck Beam & Framing Guides

Sources & Technical References

Technical references reviewed: September 2026

• International Code Council — 2021 IRC Chapter 5, Deck Beams and Beam Bearing
• International Code Council — 2024 IRC Chapter 5
• American Wood Council — Residential Deck Resources
• American Wood Council — DCA 6 (2015 IRC-Based) Prescriptive Residential Wood Deck Construction Guide
• American Wood Council — Built-Up Beam Connection Guidance
• American Wood Council — Deck Beam/Girder Bearing at Posts
• Simpson Strong-Tie — Deck Connection and Fastening Guide