A typical residential deck project moves through several major phases:

1. planning the deck size, height, layout, and materials
2. confirming permit, setback, utility, and structural requirements
3. laying out the deck and footing locations
4. constructing the foundation and support system
5. installing the ledger where an attached design uses one
6. building beams and joists
7. installing blocking and structural connections
8. installing decking
9. building stairs and landings
10. installing guards, railing, and handrails
11. completing inspections and final details

The structural work begins only after the basic deck design is understood.

Before excavation or framing, determine:

• deck dimensions
• deck height
• attached vs freestanding design
• stair location
• railing requirements
• decking material
• planned joist direction
• beam locations
• post and footing layout
• required setbacks
• utility locations
• permit requirements

This is also the stage where homeowners should decide whether the project falls within a prescriptive design path or requires additional engineering.

Start with: Deck Project Readiness Planner, Deck Permit Checklist, and Deck Cost Calculator.

A deck is a load-transfer system.

Gravity loads move through the structure approximately like this:

But a complete deck also experiences forces other than simple downward gravity loads.

Connections may need to resist:

• lateral movement
• guard loads
• stair loads
• uplift where applicable
• movement between structural members

Simpson Strong-Tie’s Deck Connection and Fastening Guide addresses the deck as a continuous load path and separately covers footings, beam-to-post assemblies, ledgers, lateral connections, joist-to-beam connections, guard posts, and stairs.

For a deeper system-level explanation, see: Deck Framing Layout Explained.

A deck is not strong simply because large lumber sizes were used.

Every structural member depends on the connections supporting it.

Critical deck connections include:

• ledger-to-house attachment
• joist-to-ledger connections
• joist-to-beam connections
• beam-to-post connections
• post-to-footing connections
• guard-post-to-framing connections
• stair-stringer connections

A correctly sized beam can still perform poorly if it does not have proper bearing or a connection designed for the load.

Likewise, guard posts, stairs, and joists depend on more than screw quantity alone.

Related: Deck Joist Hangers.

The following components make up the primary structure of a typical residential deck.

Footings spread deck loads into the soil and help resist settlement and seasonal ground movement.

Footing design depends on factors such as:

• supported tributary load
• post layout
• soil-bearing assumptions
• local frost requirements
• footing shape and depth

Footing spacing and footing size are related but not identical decisions.

See: Deck Footing Size Chart, Deck Footing Spacing, and Deck Footing Calculator.

Deck posts carry beam loads downward into the footing system.

Post layout affects:

• beam span
• footing count
• footing load
• deck stiffness
• cost

Reducing the number of posts may require larger beams, larger footings, or a different framing layout.

See: Deck Post Spacing Chart and How Many Deck Posts Do I Need?.

Beams collect load from multiple joists and transfer that load into posts.

Beam design depends on:

• beam size
• number of plies
• lumber species and grade
• joist span
• tributary load
• post spacing

Beam support matters as much as beam size. Prescriptive deck guidance generally relies on proper beam bearing or approved structural connections rather than simply fastening a beam to the side of a post and expecting the fasteners alone to carry gravity load.

See: Deck Beam Span Chart.

On many attached decks, the ledger supports one end of the joist system and connects the deck to the building structure.

Ledger construction requires careful attention to:

• attachment to appropriate house framing
• fastener type and spacing
• flashing
• water management
• lateral-load provisions where applicable

See: Deck Ledger Board and Deck Flashing.

Joists support the decking surface and transfer loads to beams, ledgers, or other structural supports.

Joist design depends on:

• joist size
• species and grade
• spacing
• unsupported span
• decking manufacturer requirements

Joist span and joist spacing are separate dimensions.

A joist may satisfy a structural span table while the selected decking product requires tighter spacing for adequate board support.

See: Deck Joist Span Chart and Deck Joist Spacing.

Blocking is installed between joists for alignment, stability, and localized structural support.

Depending on the deck design, blocking may help:

• reduce joist rotation
• maintain framing alignment
• support picture-frame borders
• reinforce guard-post locations
• support stair or framing transitions

Blocking does not automatically increase allowable joist span, but it can improve how the framing system behaves and provide required support at specific details.

See: Deck Blocking.

Accurate layout determines where nearly every later structural component will go.

Typical layout work includes:

• establishing deck dimensions
• locating the house reference line
• setting outside deck corners
• squaring the layout
• locating beam lines
• locating posts
• locating footings
• confirming stair position

String lines, batter boards, diagonal measurements, laser levels, and careful dimension checks can help prevent early layout errors from carrying through the entire project.

Footings should be located and constructed according to the approved structural layout and local requirements.

Depending on the foundation system, this stage may involve:

• excavation
• forms or tubes
• concrete
• embedded anchors
• approved post bases
• inspection before concrete placement where required

Frost depth, soil conditions, footing size, and foundation type vary by location and project.

Once the foundation is ready, the post-and-beam support system can be established according to the design.

Critical details include:

• post alignment
• post plumb
• post-base attachment
• beam elevation
• beam bearing
• beam-to-post connection

A beam should transfer gravity load into its supports through a detail designed for that load.

This is one reason beam/post connection design matters as much as beam span itself.

Where the approved attached-deck design uses a ledger, installation should follow the applicable plans, fastener requirements, and water-management details.

This stage may involve:

• removing or modifying exterior finishes where required
• locating structural house framing
• installing the ledger
• installing approved fasteners
• installing flashing
• providing lateral connections where required

Simpson Strong-Tie’s Deck Connection and Fastening Guide separately addresses ledger connections and lateral connections because they perform different structural functions.

Joists are installed according to the framing plan and supported by beams, ledgers, or other approved structural members.

Important joist-installation details include:

• layout spacing
• correct joist hangers where used
• required hanger fasteners
• proper bearing where joists sit on beams
• rim or band framing
• cantilever limits
• blocking

Connector fasteners should be selected for the connector and application rather than substituted casually with whatever screw or nail is available.

Related: Deck Joist Hangers and Deck Cantilever Guide.

Before the decking hides the frame, install required blocking and reinforcement.

This can include support for:

• guard posts
• picture-frame decking
• breaker boards
• stair openings, headers, and stringer attachment
• special framing transitions
• manufacturer-specific decking details

A cantilever occurs when a joist or beam extends beyond its supporting member.

Cantilevers can help:

• move posts inward from the deck edge
• create cleaner finished proportions
• adjust beam location
• reduce visible support at the perimeter

But allowable cantilever depends on the specific structural condition.

AWC notes that DCA 6 joist-overhang limits are affected by both deflection and the relationship between cantilever and main span; they should not be reduced to one universal overhang number.

See: Deck Cantilever Guide.

Structural framing is an interconnected set of decisions.

The old rule that composite decking simply “needs closer joist spacing” is too broad.

Many current decking products permit common residential framing such as 16 inches on center when boards are installed perpendicular to joists.

But required support can change based on:

• manufacturer
• product collection
• board profile
• installation angle
• stair use
• commercial vs residential application

Simpson Strong-Tie likewise recommends following the decking manufacturer’s fastening and spacing requirements for composite products.

Exterior deck hardware operates in a demanding environment.

Fasteners and connectors can be exposed to:

• rain
• humidity
• preservative-treated lumber
• pool or hot-tub moisture
• de-icing salts
• coastal salt exposure

Connector and fastener corrosion resistance should be appropriate for the materials and exposure conditions.

Simpson Strong-Tie recommends selecting fasteners based on the connection, exposure, and materials being fastened, and notes that stainless steel may be appropriate in elevated-corrosion environments such as locations near pools, hot tubs, sprinklers, ponds, foliage, or de-icing salts.

Prescriptive resources are extremely useful, but they only apply within the conditions they were designed to address.

AWC’s DCA 6 is a prescriptive residential wood-deck guide based on the 2015 IRC and defined assumptions and scope. AWC states that it applies to single-level residential decks attached to the house to resist lateral forces.

AWC also explains that DCA 6 structural tables were developed primarily around:

• 40 psf uniformly distributed live load
• 10 psf dead load
• defined lumber and framing assumptions

Other deck configurations, loads, materials, roof structures, hot tubs, unusual geometry, or local requirements may fall outside that prescriptive framework.

Before deck boards are installed, this is the best time to inspect the framing while every structural component is still visible.

Verify:

• joists are properly spaced
• joists are aligned and reasonably flat
• required blocking is installed
• picture-frame and breaker-board support is complete
• guard-post reinforcement is in place
• stair openings, headers, stringer attachment points, and guard-post blocking are resolved
• structural connectors and fasteners are complete
• ledger flashing and water-management details are complete

Decking forms the finished walking surface, but installation requirements vary substantially by material and product.

Important decking decisions include:

• board direction
• joist spacing compatibility
• side-to-side board spacing
• end gaps
• fastener system
• picture-frame borders
• breaker boards
• stair-board support

Composite and PVC decking are engineered products, so manufacturer installation instructions should control spacing, fastening, joist-support requirements, and other product-specific details.

Simpson Strong-Tie’s deck guidance likewise instructs installers to follow the decking manufacturer’s fastening and spacing requirements for composite products.

Continue with: Deck Board Spacing Guide, Composite Deck Board Sizes, and Hidden Deck Fasteners.

The decking material does not replace the structural framing system underneath it.

Even premium composite or PVC decking still depends on properly designed:

• joists
• beams
• posts
• footings
• connections

Compare materials in our Decking Materials Guide and Composite Decking Guide.

Water is one of the biggest long-term threats to wood deck framing.

Good deck construction should allow water to drain rather than remain trapped against structural components.

Pay particular attention to:

• ledger flashing
• house-wall transitions
• joist tops
• beam tops
• board gaps
• areas beneath planters or mats
• locations where debris collects

Simpson Strong-Tie recommends approved corrosion-resistant flashing where an attached deck meets a wood-frame wall or floor assembly to help prevent water penetration into the building.

See: Deck Flashing Guide.

Joist and beam flashing tapes are commonly used as an additional water-management layer on the tops of exposed framing members.

They are intended to reduce repeated water exposure around:

• joist tops
• beam tops
• fastener penetrations
• areas beneath decking joints

Whether a specific tape is appropriate depends on the framing material, adhesive compatibility, climate, and manufacturer instructions.

Deck stairs are one of the most layout-sensitive parts of the project because small geometry errors can affect every step in the stair run.

Stair construction involves:

• total rise and the finished landing elevation
• number of risers and actual riser height
• tread depth and total horizontal run
• stringer layout and cutting
• stringer spacing and tread support
• top and bottom stringer connections
• landing design
• stair guards and graspable handrails where required

Stair Decisions Affect the Main Deck Framing

Stairs should not be treated as an accessory that gets designed after the deck surface is complete. The stair location can affect the rim or header framing, stringer attachment, landing location, outside-stringer position, guard-post blocking, clear stair width, and the transition between the level deck guard and the sloped stair railing.

Resolve those conditions while the framing is still open. Moving an outside stringer, adding a stair header, or creating guard-post blocking after the decking is installed can turn a straightforward framing detail into a retrofit.

Simpson Strong-Tie’s Deck Connection and Fastening Guide treats stair-stringer and tread connections as distinct structural details within the deck system. AWC DCA 6 also illustrates stair stringers, tread attachment, stair guards, and stringer-to-deck attachment within its stated prescriptive scope.

Deck railing is not merely a decorative finish. Where a guard is required, its posts and connections must transfer loads into the deck framing.

Railing construction can involve:

• guard-post attachment
• structural blocking
• rail sections
• balusters or other infill
• stair guards
• graspable handrails
• gates

Simpson Strong-Tie’s deck connection guidance includes dedicated details for guard-post-to-framing connections and guardrail assemblies, emphasizing that these are structural connections rather than surface-mounted decoration.

Continue with: Deck Railing Guide, Deck Railing Code, Deck Railing Post Spacing, and Deck Railing Calculator.

Many deck problems begin with small decisions made early in construction.

Common mistakes include:

• digging footings before the structural layout is finalized
• using generic span assumptions without verifying species, grade, load, and spacing
• spacing posts based on convenience rather than beam design
• using inadequate beam bearing or connections
• attaching a ledger without proper flashing
• using incorrect fasteners in structural connectors
• ignoring corrosion compatibility
• forgetting blocking beneath guard posts or picture-frame borders
• installing decking without checking manufacturer joist-spacing requirements
• using improper board gaps
• designing stairs after the main deck is already complete
• treating railing posts as nonstructural trim

Nails, screws, bolts, structural screws, and connector fasteners are not interchangeable simply because they physically fit.

Connector and fastener selection can depend on:

• connection type
• required capacity
• connector manufacturer instructions
• preservative-treated lumber
• exterior exposure
• corrosion environment

Simpson Strong-Tie’s guidance recommends selecting fasteners based on the importance of the connection, environmental exposure, and the materials being fastened.

Hiring a contractor does not eliminate the need for homeowner due diligence.

Before signing, understand:

• the structural scope
• exact decking and railing products
• permit responsibility
• allowances and exclusions
• payment schedule
• change-order process

See: Questions to Ask a Deck Contractor and Deck Quote Comparison Tool.

Compare Your Estimate With Local Deck Contractor Quotes

A national cost range is useful for establishing a budget, but it cannot account for your local labor market, site access, permit requirements, material availability or exact project scope.

Once you know the approximate deck size, material, railing, stairs and construction scope, use that information to request local proposals for the same project.

Affiliate disclosure: The Backyard Standard may earn a commission if you submit a service request through this link.

Deck construction cost depends on far more than square footage.

Major cost drivers include:

• deck size
• deck height
• framing design
• footing count and foundation conditions
• decking material
• railing type and length
• stairs
• demolition
• site access
• permit requirements
• labor market

A simple ground-level pressure-treated deck and an elevated composite deck with stairs, aluminum railing, fascia, lighting, and complex foundations are not meaningfully comparable on square footage alone.

Start with the Deck Cost Calculator and our Deck Framing Cost Guide.

The Backyard Standard calculators are designed to follow the same decisions involved in an actual deck project.

Accurate layout and measurement matter throughout deck construction. The following tools are particularly useful across multiple stages of a deck project.

Calculated Industries Construction Master Pro 4065

Best for: Construction math, rise-and-run calculations, framing dimensions, stair layout, and general project calculations.

View Construction Master Pro 4065 →

Bosch GLM165-40 BLAZE Laser Distance Measure

Best for: Measuring deck dimensions, beam runs, post layouts, stair openings, and railing lengths.

View Bosch GLM165-40 →

DEWALT DW088LG Green Cross-Line Laser

Best for: Establishing reference lines, checking framing elevations, and assisting with layout across larger projects.

View DEWALT DW088LG →

Swanson Speed Square

Best for: Framing layout, marking square cuts, checking angles, and general deck construction.

View Swanson Speed Square →

See the complete: Recommended Deck Building Tools Guide.

As an Amazon Associate, The Backyard Standard earns from qualifying purchases, at no additional cost to you.

Before treating the project as complete, inspect the deck as a system rather than only looking at the finished decking surface.

Review:

• footings and post bases
• post alignment
• beam bearing and connections
• joists and hangers
• ledger attachment
• flashing
• structural hardware
• deck-board fastening
• board spacing
• stairs and landings
• guard stability
• handrails
• required inspections

Simpson Strong-Tie’s deck connection guidance includes critical-connection and concealed-connection checks, reinforcing the importance of reviewing connection details before they become difficult to access.

Use our: Deck Inspection Checklist.

What are the basic steps to building a deck?

A typical deck project includes planning and permits, layout, footings, posts and beams, ledger installation where applicable, joists, blocking, decking, stairs, guards or railing, and final inspection. The exact sequence varies with deck design and local inspection requirements.

What is the most important part of deck construction?

There is no single isolated component that makes a deck safe. The most important concept is a complete structural load path from decking and joists through beams, ledgers, posts, footings, connections, and soil.

Should deck posts be installed before the ledger?

There is no universal sequence for every deck. Attached and freestanding designs differ, and construction order may also depend on the approved plan, site conditions, and inspection sequence.

What is the difference between an attached and freestanding deck?

An attached deck commonly uses a structural ledger connection to the house, while a freestanding deck uses an independent support system rather than relying on the building for that structural support.

How far apart should deck joists be?

Joist spacing depends on the structural design and the decking product. Many residential decking products allow 16-inch-on-center framing in common perpendicular installations, while other products or layouts may require tighter spacing. Follow the exact product’s installation requirements.

How far apart should deck posts be?

Post spacing depends on beam size, joist span, tributary load, lumber properties, and the overall structural design. There is no universal post-spacing number for every deck.

Do deck beams need to sit on top of posts?

Gravity loads need a properly designed load path into the post. Prescriptive wood-deck framing commonly uses direct beam bearing or an approved connection designed for the load rather than relying solely on bolts or fasteners through the side of the post.

Does composite decking need 12-inch joist spacing?

Not universally. Some products allow 16-inch-on-center residential framing for perpendicular installations, while diagonal decking, stairs, particular profiles, or manufacturer requirements may call for 12 inches on center or another spacing.

Do I need blocking between deck joists?

Blocking may be required or useful for joist stability, picture-frame borders, breaker boards, guard-post attachment, stair openings, and other localized structural details. Blocking requirements depend on the design.

Can I use regular deck screws in joist hangers?

Do not substitute generic deck screws for required hanger fasteners unless the connector manufacturer specifically approves them for that connector and application.

Do I need flashing behind a deck ledger?

Attached wood-frame deck connections require appropriate water-management detailing. Flashing is used to prevent water from entering the building and damaging the ledger or adjacent house framing.

Do deck footings need to go below frost depth?

Foundation depth depends on local code, climate, foundation type, soil, and project design. In frost-prone jurisdictions, deck foundations commonly must address frost movement, but the exact requirement should be verified locally.

Can I build a deck myself?

Many homeowners successfully build simple decks, but structural layout, foundations, ledger attachment, stairs, guards, permits, and connections require careful execution. Complex or elevated projects may warrant professional construction or engineering.

What deck construction guide should I use?

Use your adopted local code and approved plans as the controlling requirements. Prescriptive resources such as AWC DCA 6 can be useful when the deck falls within their stated scope, while manufacturer instructions control proprietary decking, railing, connectors, and related products.

Good deck construction is not about memorizing one joist span, one post-spacing number, or one footing diameter.

A durable deck is created by coordinating:

• the foundation
• posts
• beams
• joists
• ledger where applicable
• connections
• water management
• decking
• stairs
• guards and handrails

Each component has to perform its own job while transferring loads safely into the next part of the structure.

Last reviewed: September 2026

• American Wood Council — Residential Deck Resources
• American Wood Council — DCA 6 Prescriptive Residential Wood Deck Construction Guide (2015 IRC basis)
• Simpson Strong-Tie — Deck Connection & Fastening Guide
• Simpson Strong-Tie — Deck Construction & Fastening Tips