Deck Estimating: Materials, Labor, and Margin Killers
Composite decking does not cost twice what pressure treated costs. The boards do. The frame underneath is the same pressure-treated lumber either way, built the same way, by the same crew, in the same two days, and it is where most of the money and nearly all of the risk actually sits. Bidding a deck off the decking is how you end up eating the part nobody looked at.
The frame under a composite deck is a pressure-treated frame
Joists, beams, posts, hangers, hardware: identical. What changes when a client upgrades to composite is the walking surface and usually the railing, and that is the whole delta. Yet the industry talks about deck cost as one blended per-square-foot number, and homeowners arrive believing composite is a different category of project rather than a different board on the same structure.
That framing costs you twice. The client thinks the upgrade is bigger than it is and hesitates, and you lose an easy margin add. Then, when they do upgrade, the blended number quietly under-recovers the framing labor because you priced the whole job off a decking rate. Separate the two on the estimate and both problems go away.
Installed pressure-treated decks commonly run in the twenties to forties per square foot in 2026, composite in the forties to seventies. Read those ranges as what they are: two surfaces on one frame, not two projects.
The ledger is the smallest line and the largest liability
A ledger is a few hours, a couple hundred dollars of lumber, flashing and structural fasteners. It is also the connection that decides whether the deck stays attached to the house. The American Wood Council's prescriptive deck guide (DCA 6) specifies the bolt or screw pattern, the spacing, the edge distances, and the flashing detail, and it exists because ledger attachment is not something to eyeball.
The estimating problem is that you cannot see what you are bolting to until you pull siding. Rim joist or brick veneer, sound framing or twenty years of water behind a missing flashing, a cantilevered floor you cannot bolt through at all. Each of those is a different day.
Price the ledger with a stated assumption and an exclusion beside it. "Ledger assumes attachment to sound rim joist; rot repair or a freestanding frame priced separately." That sentence takes ten seconds and is the difference between a change order and an argument.
Footings are priced by the hole, not by the post
Six footings is a number. Six footings in clay, forty-two inches down, in a backyard with a thirty-inch gate and no machine access is a completely different number, and the estimate that says "6 footings" carries no information about which one you are walking into. Frost depth is set by your jurisdiction and it is not negotiable, so the depth is a given. Everything else about the hole is a variable.
The three that move the price: access, which decides whether an auger gets there or a crew digs; soil, which decides how fast the hole opens and whether it stays open; and spoil, because the dirt from six deep footings does not vanish. If you have priced concrete work before, this is the same lesson as ordering yardage over the plan number, arriving from a different direction.
"I used to quote footings at a flat rate per hole because that is what everybody does. Then I did two decks the same month, same size, same depth. One took a morning with the auger. The other was four guys with post-hole diggers for a day and a half because the only way in was through a gate. Same line on both estimates. I lost about $1,800 on the second one and it was my own handwriting that did it."
Hidden fasteners cost labor, not material
The clip systems that give a composite deck its unbroken surface install materially slower than face-screwing a pressure-treated board, on the order of a quarter to a third more labor for the same square footage. Contractors price the clips, because clips have a price on an invoice. They forget the hours, because hours do not.
This is the most common way a composite deck comes in under water while the material takeoff was perfectly accurate. The boards were right. The fasteners were right. The labor line was copied off the last pressure-treated job.
Carry two labor rates for decking installation, one for face-screwed and one for hidden-fastener, and let the estimate pick. Heading into the 2026 fall build season, with composite share still climbing, the crew that has not separated those rates is quietly subsidising every upgrade it sells.
Bid a deck as three numbers, and show all three
Frame, surface, and access. The frame is the structure and the connections, and it barely moves with the client's taste: a forty-foot deck needs the same beam whether the boards on top cost two dollars or nine. The surface is boards, railing, fasteners and stairs, and it moves entirely with taste. Access is the yard, the gate, the slope and the tear-off, and it moves with nothing the client chose and everything they already own.
Splitting them does three jobs at once. It shows the client exactly what an upgrade costs, which sells upgrades. It protects the framing labor from being averaged away. And it puts access on the page as a real cost rather than a surprise, which is the line most likely to be disputed later precisely because it was never named.
Here is where a reasonable deck builder will disagree with us: stop quoting decks per square foot at all, even as a ballpark on the phone. The number is a comparison tool for homeowners and a trap for you, because it invites a client to weigh your bid against a neighbour's on a metric that hides the ledger, the footings and the gate. If they want a range before you walk it, give a range for the frame and say the surface depends on what they pick. That is a real answer, and it is also honest about what you do not yet know. Your deck estimates get compared on structure instead of on a per-foot number that means nothing.
Before your next deck bid this week, go back to the last three you built and write down what the footings actually took: hours, access, and whether the auger made it into the yard. Three data points will tell you more about your real footing cost than any published rate, because they happened in your soil with your crew. Put the number that comes out of that on your estimate template as its own line, with the access assumption written beside it.
A deck is the one project where the client will spend twenty years looking at the part that cost the least and never once think about the part holding it up. Price it in that order and it works out. Price it the way they see it and the ledger, the footings and the gate come out of your margin.
Frequently Asked Questions
How much should a contractor charge to build a deck?
Installed pressure-treated decks commonly run in the twenties to forties per square foot in 2026, with composite in the forties to seventies. Build the number from the frame, the surface and the access separately, because only the surface moves with what the client picks.
Why does composite decking cost more than pressure treated?
The boards and railing cost more, and the hidden-fastener clip systems install about a quarter to a third slower than face-screwing. The frame underneath is identical pressure-treated lumber, so the upgrade is a surface cost, not a whole different project.
What do contractors forget to include in a deck estimate?
Ledger conditions behind the siding, footing access, and spoil removal. All three are invisible when the bid is written and expensive once the crew arrives. Each needs a stated assumption on the estimate rather than a number that pretends the answer is known.
Should I price a deck per square foot?
It is a comparison tool for homeowners and a trap for the contractor, because it hides the ledger, the footings and the yard access. If a client wants a number before you walk the job, give a range for the frame and price the surface once they choose.
What is DCA 6 for deck construction?
DCA 6 is the American Wood Council prescriptive residential wood deck construction guide. It sets the ledger fastener pattern, spacing, edge distances and flashing detail, along with joist spans and footing guidance, and it meets or exceeds the residential code minimums.
