As an Amazon Associate I earn from qualifying purchases.
A 14x20 deck covers 280 square feet and costs about $4,928 – $7,700 installed in pressure-treated pine, up to $10,752 – $16,800 in composite. It takes about 33 decking boards at 20 ft, 16 joists, 4 footings and 48 linear feet of railing.
| Material | Installed cost |
|---|---|
| Pressure-Treated Pine | $4,928 – $7,700 |
| Cedar | $7,168 – $11,200 |
| Redwood | $8,512 – $13,300 |
| Composite (Trex/TimberTech) | $10,752 – $16,800 |
| PVC / Cellular | $12,992 – $20,300 |
| Ipe / Tropical Hardwood | $14,560 – $22,750 |
A 14x20 deck is 280 square feet. In pressure-treated pine, expect roughly $4,928 – $7,700 installed. Cedar runs about $7,168 – $11,200 and composite about $10,752 – $16,800. Building it yourself typically removes 40 to 55 percent of those figures, because labour is around half of a finished deck price.
Laying boards across the 14 ft direction, you need 30 rows — that is 600 linear feet of decking, or about 33 boards at 20 ft with a waste allowance. A 20 ft board crosses the deck in one piece, so there are no butt joints.
About 4, one under each post, with posts at no more than 8 feet along the beam. That is roughly 0.49 cubic yards of concrete for 12 inch tubes poured 42 inches below grade — around 23 eighty-pound bags. Your own frost depth sets the real number and is not negotiable.