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Pergola cost by size, material and mounting — kit, DIY or built in place.
With these inputs:
| Result | Value |
|---|---|
| Estimated pergola cost | $4,212 – $7,352 |
| Per square foot | $29 – $51 |
| Footprint | 144 sq ft |
| Posts | 4 |
| Structure and rafters | $2,592 – $4,320 |
| Post bases on the deck | $180 – $440 |
| Installation labour | $1,440 – $2,592 |
Material is the whole story on a pergola: the same 12 by 12 footprint runs about $1,584 in pressure-treated lumber and about $13,680 in louvred aluminium before labour. Mounting on an existing deck is much cheaper than new footings, but only works if the deck frame can take the uplift — a pergola catches wind, and post bases have to resist it being lifted, not just pushed. Ranges are national estimates and exclude electrical, lighting and screening.
A pergola is the cheapest way to get shade and definition over a deck without the structural weight of a roof. Price swings hugely with material, though: a cedar DIY build and a powder-coated aluminium louvred system over the same footprint can differ fourfold. This prices all of them and shows what you are paying for.
A 12 by 12 ft pergola runs about $1,800 to $3,000 in pressure-treated lumber as a DIY build, $2,800 to $4,700 in cedar, and $8,300 to $14,200 for a louvred aluminium system installed. Contractor labour typically adds $10 to $22 per square foot depending on material. Mounting on new concrete footings adds $1,100 to $2,500 over setting it on an existing deck.
Building in place from cedar or pressure-treated lumber is usually 25 to 40 percent cheaper in materials than a comparable kit, but it takes a weekend or two and needs accurate rafter cuts. Kits win on speed, on consistent appearance, and on aluminium and vinyl where you cannot fabricate the parts anyway. For a simple square pergola in wood, building it is the better value.
Usually, with two checks. The posts need to land over a joist, a beam or blocking — not on decking alone — and the connection has to resist uplift, because a pergola behaves like a sail in a storm. Use rated post bases through the decking into the frame. If the deck is elevated and the posts land mid-span, add blocking or a post down to a footing.
It depends on size and attachment. Many jurisdictions exempt a freestanding pergola under a set footprint, commonly 100 to 200 square feet, but require a permit once it attaches to the house or exceeds that. Anything with a solid or louvred roof is more likely to count as a structure. One call to the building department settles it.
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.