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Compare installed cost per square foot across materials.
With these inputs:
| Result | Value |
|---|---|
| Installed cost per sqft | $48.00 |
| Total project cost | $9,600 |
| Material | Composite (Trex/TimberTech) |
Cost per square foot is the number every quote gets compared against, and the number most often quoted without saying what it includes. A price that covers only decking boards and a price that covers footings, framing, railing, stairs and labour can differ by a factor of four for the same deck. This works out a per-square-foot figure from your own inputs and shows exactly which line items are inside it, so you can line it up against a contractor's bid on equal terms.
Installed, most residential decks land between $30 and $60 per square foot. Pressure-treated pine sits at the bottom of that band, cedar in the middle, composite around $45 to $60, and PVC or tropical hardwood above it. Materials alone are usually 40 to 50 percent of the total; the rest is labour, footings, hardware and the permit.
Because the phrase covers different things. Some quotes are decking material only, some are materials and framing, and some are the finished job including stairs, railing and site work. Height matters too: an elevated deck needs taller posts, deeper footings and staging, so the same boards over the same footprint cost more. Always ask what is inside the number before comparing two.
Usually, yes. Fixed costs — mobilisation, the permit, the ledger, the stairs — spread over more area, and long joist runs waste less lumber. The saving is real but modest, in the region of 10 to 15 percent going from a small deck to a large one. It reverses once the deck gets big enough to need a second beam line or a multi-level layout.
On pressure-treated pine, labour is usually the larger half, often 55 to 60 percent. On composite and PVC the material share climbs and labour drops below half, because the boards cost several times more while the work of installing them is nearly identical. That is why upgrading material costs less overall than the sticker difference suggests.
About $48 per square foot installed, the composite rate this calculator uses for Trex, TimberTech and Fiberon. That is roughly $9,216 for a 12×16 deck and $15,360 for a 16×20. Premium capped board lines cost more per board than entry lines, so a top-tier composite quote can approach the $58 PVC rate.
A 12×16 deck is 192 square feet, so at installed rates it is about $4,224 in pressure-treated pine, $6,144 in cedar, $9,216 in composite, $11,136 in PVC and $12,480 in ipe. Add 20 to 40 percent for multiple levels, curves or built-ins.
An 8×10 deck is 80 square feet, so at installed rates it is about $1,760 in pressure-treated pine, $2,560 in cedar, $3,840 in composite and $4,640 in PVC. Small decks run a little above the per-square-foot rate because the stairs, ledger and permit are fixed costs spread over fewer feet.
A 10×20 deck is 200 square feet: about $4,400 in pressure-treated pine, $6,400 in cedar, $9,600 in composite and $11,600 in PVC, installed with code-minimum railing and one stair run. The 10x20 deck page has the full material list and the low-to-high range.
A 14×14 deck is 196 square feet: about $4,312 in pressure-treated pine, $6,272 in cedar, $9,408 in composite and $11,368 in PVC. The 14x14 deck page works out the joist size each lumber species needs for that 14 ft span, plus the material list.
A 16×16 deck is 256 square feet: about $5,632 in pressure-treated pine, $8,192 in cedar, $12,288 in composite and $14,848 in PVC. These are national averages; the 16x16 deck page gives the low-to-high range and the full material list.
Multiply length by width — 12 ft by 16 ft is 192 square feet. For an L-shape, split it into rectangles and add them. Stairs are priced per step, so leave them out of the square footage and add them separately.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.