What a roof replacement actually costs

The national number, and why it misleads

The national average for a roof replacement is $10,000, with most jobs landing between $7,500 and $14,000 — about $4.75 per square foot of roof, against a full spread of $3.75 to $11.00. That spread is the whole story: the average sits nowhere near either end, and which end you land at is decided by three things — the material, how much old roof comes off first, and how hard the roof is to stand on.

Cost per square by material

Every price in this trade is quoted per square — one hundred square feet. Here is the installed range for each covering, material and labour together.

Architectural asphalt has the widest band of any covering because the label covers both a mainstream laminate and a heavy designer profile imitating slate. Read the grade comparison before you take a quote at the bottom of that range as like-for-like.

Tear-off, deck and the things nobody sees

Stripping the old roof runs $50 per square for a clean single layer. Two or three layers, or a heavy covering that fills a dumpster by weight, takes it to $150 per square. On a 21-square roof that is the difference between $1,050 and $3,150 before a single shingle is laid.

Then there is the deck. Sheathing replacement runs $2 to $8 per square foot, and nobody can quote it honestly until the covering is off. A contractor who names a per-sheet rate and a contingency percentage is being straight with you; one who promises no deck cost is not.

Where the labour half goes

Labour is 40 to 60% of an installed roof price. That share does not buy craftsmanship in the abstract — it buys tear-off, carrying material up a ladder, cutting valleys, flashing three penetrations properly instead of caulking them, and cleaning the yard with a magnet. It also tracks local wages: a roofer’s annual mean pay varies by more than $30,000 between the highest and lowest states, and that gap lands directly in the per-square rate. The wage data shows where your market sits.

A worked takeoff

A 48 × 34 ft ranch: 1,632 sq ft of footprint, 6/12 pitch, hips at both ends and one valley. The pitch multiplier takes the surface to 1,825 sq ft — 18.25 squares — and 15% waste for the hips and valley makes the order 21 squares. In mainstream architectural asphalt that is roughly $9,975 of covering plus $1,050 of tear-off, with a five per cent deck contingency on top. Run your own numbers on the replacement cost calculator.

Reading three bids against each other

Bids are only comparable line by line. Check that all three quote the same square count — if one is materially lower, someone measured the footprint instead of the roof. Check that starter strip, hip and ridge cap, drip edge and all new flashing appear as their own lines; reused flashing is the most common silent saving. Check the underlayment spec and whether ice-and-water membrane is included at the eaves. Then compare the deck contingency: the bid that names one is usually the bid that finishes at its own price. The estimate template is the shape a complete bid should take.