A deck ledger board is a horizontal structural board fastened to the house framing. Deck joists attach to the ledger with joist hangers, allowing the deck frame to extend outward from the house.

Ledger boards are commonly made from pressure-treated lumber and are usually sized to match the deck joists, such as:

• 2×8 ledger
• 2×10 ledger
• 2×12 ledger

The ledger supports the house-side end of the deck joists, while beams, posts, and footings support the outer portion of the deck.

Ledger board failures are one of the most serious causes of deck collapses because the connection ties the deck directly to the house.

If the ledger loosens, rots, or pulls away from the house, the deck can separate from the structure.

Common causes of ledger failure include:

• missing or poorly installed flashing
• fasteners installed only into sheathing
• attachment to siding or veneer
• incorrect fastener type
• insufficient fastener spacing
• rotted rim joist behind the ledger
• corroded bolts or screws

Attached decks follow a structural load path:

The outer side of the deck transfers load through:

In many attached residential decks, the ledger supports a large share of the deck load while the beam and posts support the outer side.

Related: Deck Joist Span Chart, Deck Beam Span Chart, Deck Post Spacing Chart, and Deck Footing Size Chart.

Ledger boards must attach directly to structural framing members capable of carrying deck loads.

Acceptable attachment points may include:

• solid wood rim joists
• structural band joists
• approved engineered rim boards
• properly evaluated structural framing behind siding

Ledger boards should not attach directly to:

• vinyl siding
• wood siding
• brick veneer
• stone veneer
• stucco finishes
• cantilevered floor systems unless specifically engineered

If the house framing cannot safely accept a ledger, a freestanding deck is usually the safer design.

Ledger boards are usually sized to match the deck joists.

Ledger boards must be attached with structural fasteners rated for load-bearing deck connections.

Fasteners should be corrosion-resistant and compatible with pressure-treated lumber. Hot-dipped galvanized or stainless steel fasteners are commonly used depending on exposure conditions and manufacturer requirements.

Ledger fastener spacing depends on joist span because longer joists transfer more load into the ledger connection.

The following chart provides planning-level spacing commonly associated with prescriptive residential deck guidance.

Ledger fastener spacing is based on load.

As deck joist span increases, the ledger supports a larger tributary area. That increases the load transferred into the house framing.

General structural relationship:

• shorter joists → less ledger load → wider fastener spacing may be allowed
• longer joists → more ledger load → closer fastener spacing is required

This is why ledger spacing charts become tighter as joist span increases.

Related: Deck Joist Spacing.

Modern deck standards often require lateral load connectors for attached decks. These connectors help prevent the deck from pulling away from the house.

Lateral connectors resist horizontal forces caused by:

• people moving or leaning on the deck
• wind loads
• deck movement over time
• outward pulling forces at the ledger

Many prescriptive deck designs use two lateral load connections that tie the deck framing back into the house framing.

Flashing protects the ledger connection from water intrusion. Without flashing, water can enter behind the ledger and rot the house rim joist or wall sheathing.

Common ledger flashing components include:

• self-adhered waterproof membrane behind the ledger
• metal or PVC cap flashing above the ledger
• integration with the home’s weather-resistant barrier
• proper drainage path away from the house

Flashing should be installed in layers so water sheds outward rather than becoming trapped behind the ledger.

A durable ledger connection usually uses a layered water-management approach.

Typical installation layers:

1. house framing and sheathing
2. weather-resistant barrier
3. self-adhered flashing membrane
4. pressure-treated ledger board
5. metal or PVC cap flashing above the ledger
6. siding or exterior finish integrated over flashing

Some builders use spacers behind the ledger board to create a small drainage and airflow gap.

This gap can help reduce trapped moisture and allow the wall assembly to dry more effectively.

A drainage gap may help reduce:

• trapped moisture
• wood rot
• mold growth
• long-term sheathing deterioration

Any spacer system must still preserve structural load transfer and use approved fasteners.

A ledger board is not appropriate for every house.

A freestanding deck is often safer when:

• the home has brick veneer
• the home has stone veneer
• the wall has stucco or complex cladding
• the floor system is cantilevered
• the rim joist is inaccessible or weak
• water intrusion risk is unusually high
• proper flashing cannot be installed

A freestanding deck requires additional posts and footings near the house, but it avoids relying on the house wall for structural support.

Proper ledger installation requires careful sequencing.

Typical installation process:

1. Locate structural framing behind the exterior wall.
2. Remove siding where the ledger will be installed.
3. Inspect the rim joist and sheathing for rot or damage.
4. Install self-adhered flashing membrane.
5. Position the pressure-treated ledger board.
6. Install structural fasteners using approved spacing.
7. Install metal or PVC flashing above the ledger.
8. Attach joists with approved joist hangers.
9. Install lateral load connectors where required.

Ledger boards can damage homes when water gets trapped between the deck and house wall.

Over time, trapped moisture can cause:

• rim joist rot
• sheathing deterioration
• mold growth
• fastener corrosion
• structural weakening

Because much of this damage occurs behind the ledger and inside the wall assembly, homeowners may not see the problem until it becomes serious.

Most ledger failures are caused by installation errors or water damage rather than the ledger board itself.

Common failure causes:

• missing flashing
• ledger fastened through siding
• fasteners installed only into sheathing
• incorrect fastener spacing
• corroded fasteners
• rotted rim joist
• missing lateral load connectors
• unsupported side-mounted connections

Homeowners inspecting an older attached deck should pay close attention to the ledger connection.

Warning signs include:

• missing or damaged flashing
• gaps between the ledger and house
• loose bolts or screws
• rusted fasteners
• soft or rotted wood near the ledger
• water stains below the ledger
• deck movement near the house
• joist hangers pulling away from the ledger

• attaching the ledger over siding
• attaching to brick or stone veneer
• using nails instead of structural fasteners
• skipping flashing
• using non-corrosion-resistant fasteners
• ignoring lateral load connectors
• reusing a damaged rim joist
• installing joist hangers incorrectly

What is a deck ledger board?

A deck ledger board is a horizontal structural board that attaches an attached deck to a house and supports the deck joists on the house side.

How far apart should ledger bolts be spaced?

Ledger fastener spacing depends on joist span, deck load, fastener type, and code requirements. Planning-level spacing commonly ranges from about 11 to 30 inches.

Can a deck ledger attach to brick?

A ledger board should not attach directly to brick veneer because veneer is not a structural support system.

What size ledger board should be used?

Ledger boards usually match the joist size, commonly 2×8, 2×10, or 2×12 pressure-treated lumber.

Does a deck ledger need flashing?

Yes. Flashing is essential because it prevents water from entering behind the ledger and damaging the house framing.

When should a deck be freestanding?

A freestanding deck is often safer when the house has brick veneer, stone veneer, cantilevered framing, inaccessible rim joists, or high water-intrusion risk.

Are nails acceptable for ledger attachment?

No. Ledger boards require approved structural fasteners such as lag screws, through bolts, or engineered structural ledger screws.

A deck ledger board is one of the most important structural connections in an attached deck. It transfers loads from the deck joists into the house framing and must be installed with proper fasteners, flashing, drainage, and lateral load resistance.

The safest ledger connections attach directly to structural framing, use approved corrosion-resistant fasteners, include layered flashing, and are protected from trapped moisture.

If proper ledger attachment is not possible, a freestanding deck supported by posts and footings is usually the better structural choice.

Last reviewed: May 2026

• American Wood Council
• International Code Council
• North American Deck and Railing Association