Deck building: what to know

What the job involves, what changes the price, and what to ask a pro.

What deck building is

Deck building means designing and framing an outdoor platform with footings, a joist and beam structure, decking boards, railings and stairs, then finishing it to suit the weather. People call for a new deck when an old one has failed, when they want more living space outside, or when a yard needs a raised surface that works with the slope and the house.

Signs you need it

  • An existing deck is sagging, bouncy or pulling away from the house, and the frame is no longer stable
  • There is no deck or the current one is too small for the furniture, grill and gathering space you need
  • A patio or yard slopes too much for a flat outdoor space, and a raised deck would level the use area
  • A door opens onto a drop or a step down, and a deck with stairs would make the exit safe to use
  • The current deck is so weathered or rotted that repairs would cost more than a new structure
  • You want a deck with a particular material, such as composite or cedar, and a new build lets you choose the frame and boards

What the pro does

  • Review the site, the house attachment point, the grade and the local rules, and draw a plan the pro can build from
  • Dig and pour footings below the frost line where required, and set post bases or piers at the marked locations
  • Attach a ledger board to the house with proper flashing and lag or through-bolts, since the ledger carries much of the load
  • Frame the beams, joists and posts, and set the joist spacing to suit the decking boards you chose
  • Install decking boards with the correct gap for the material, then build the stairs and the railing posts
  • Fasten the railings and the guards at the required height, and finish the deck with a stain, sealer or the manufacturer's coating

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Deck size, height off the ground and shape, since a high deck needs taller posts, more bracing and more railing
  • Decking material, such as pressure-treated pine, cedar, hardwood or composite, each with different cost and install time
  • Number and depth of footings, and whether soil conditions require deeper holes or helical piers
  • Attachment to the house, including the ledger work and the flashing that protects the wall
  • Stairs, landings and railing style, such as cable, glass or traditional balusters
  • Permit and inspection requirements that set the number of stages the work must pass
  • Demolition and hauling of an existing deck, if it has to come out first

What a written quote should spell out

  • Deck dimensions, height and the decking material and brand named in the proposal
  • Footing count, size and depth, and the post and beam sizes used
  • Ledger attachment method, flashing details and the fasteners named
  • Railing and guard height, baluster spacing and stair details, as the local rules require
  • Permit fees, drawings and inspection stages, with who pulls the permit
  • Finish type, stain or sealer product, and the warranty on the boards and the workmanship

Questions to ask before you hire

  • How are you attaching the deck to the house, and what flashing goes behind the ledger?
  • How deep are the footings, and do they go below the frost line where I live?
  • What size joists and beams are you using for this span and height?
  • Which decking material do you recommend for my use, and what does the warranty cover?
  • Who pulls the permit, and how many inspections will the job need?
  • What guard height and baluster spacing do you build to, and how do you check it?

Red flags

  • Attaches the ledger directly to the siding or the house wall with no flashing behind it
  • Sets the footings on the surface with no digging or no frost-depth check
  • Skips the joist hangers or uses nails where bolts or structural fasteners are required
  • Builds a high deck with railings that are not tied into the structure at the posts
  • Says a permit is unnecessary without checking the local rules for the deck's height and attachment

What you can do yourself

A homeowner can build a low, simple deck attached to nothing, or a ground-level platform, when the design and the footings are reviewed by a pro or the local building department. Call a pro for any deck attached to a house, any deck over the height of a short step, and any deck with stairs or railings, since failed ledgers and guards cause serious falls and collapses. Power tools, lumber handling and work at height all carry risk, so wear eye and hearing protection, gloves and a harness where the height calls for one.

Licenses and permits

Deck building is commonly done by licensed contractors, and many areas require a permit for a new deck, especially one attached to a house or raised off the ground. Check with your state or local licensing agency and your local building department before work starts, since the rules cover footings, attachment and railings.

Deck building questions

How long does a new deck last?

The life of a deck depends on the material, the attachment, the drainage under it and how well the finish is kept up. Ask the pro what they recommend for upkeep and when the finish needs to be redone.

Is composite better than wood for a deck?

Composite needs less upkeep and does not rot the way wood does, but it costs more and can get hot in full sun. Ask the pro to show samples and the warranty for each option before deciding.

Why does my deck need inspections?

Inspections check that the footings, the ledger, the framing and the railings are built to the local rules and can carry the loads they will see. Ask the pro when each inspection is scheduled and make sure they happen before the next stage is covered.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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