Replacing an asphalt shingle roof costs $8,000 to $20,000 for a typical single-family home, with most mid-size jobs landing between $11,000 and $15,000. The unit that matters is the roofing square, which is 100 square feet of roof area, and architectural shingles run $450 to $750 per square installed with tear-off, underlayment, and cleanup included. Quotes outside that band usually have a story: brutal access, rotten decking, or a premium material.
That’s the entire pricing model. Everything else is your roof’s geometry and condition stacking multipliers on top of it, and every line below is something you can check against any quote you’re handed.
What Actually Drives the Price
| Cost component | Typical range | Notes |
|---|---|---|
| Tear-off and disposal | $80 - $150 per square | Two existing layers cost more than one |
| Architectural shingles | $150 - $250 per square | Material only |
| Underlayment and ice barrier | $30 - $80 per square | Synthetic felt, plus ice-and-water at eaves and valleys |
| Flashing, drip edge, pipe boots | $500 - $1,500 per job | Climbs with chimneys and skylights |
| Decking replacement | $90 - $150 per sheet | Charged per 4x8 sheet once rot is found |
| Labor | $200 - $350 per square | Climbs with pitch and height |
| Permit | $100 - $500 | Varies a lot by town |
Add those up on a clean 20-square roof and you land between roughly $9,800 and $18,600 depending on where each line sits, which is how the overall $8,000-to-$20,000 range gets built. Notice that the shingles themselves are rarely the biggest line. Tear-off and labor combined usually cost more than the shingle material does, which is why two quotes on the same brand can sit thousands of dollars apart.
The Per-Square Math, Step by Step
Roofers measure in squares, and squares come from the roof, not the floor plan. A 1,800 sq ft ranch with a 6/12 pitch does not have 18 squares of roof. Slope adds area. Overhangs add more.
The arithmetic takes a minute. Multiply your footprint by a pitch factor: 1.05 at a 4/12 pitch, 1.12 at 6/12, 1.20 at 8/12, and 1.41 at 12/12. Then add roughly 5 percent for eave and rake overhangs. So the 1,800 sq ft ranch at 6/12 works out to 1,800 × 1.12 × 1.05, or about 21 squares.
At $550 to $650 per square installed, that roof prices out between $11,500 and $13,600 before surprises. You can run this on any quote you get in five minutes. Steep and tall roofs break the math upward: a two-story colonial at a 10/12 pitch can easily exceed $900 per square once harnesses, staging, and slower crew movement get priced in.
Three Real-World Scenarios
21-square ranch, Kansas City, 6/12 pitch, single story. One layer torn off, synthetic underlayment, ice-and-water shield at the eaves, new pipe boots and valley metal, plus three sheets of decking replaced after tear-off revealed rot. Total: $13,200. The decking was the only surprise, and it came from a $135-per-sheet line item nobody can confirm until the shingles are off the deck.
26-square two-story colonial, Denver, 10/12 pitch. Same architectural shingle as the ranch, but steep-pitch labor rates, a new ridge vent, and chimney reflashing at $1,100 push this one up. Parts and materials $8,900, labor and staging $11,200, permit and disposal $1,300. Total: $21,400. Nothing here is gold-plated; pitch and height are just expensive.
14-square single-story ranch, Atlanta, 4/12 pitch. Walkable roof, one layer off, easy driveway access, simple valleys, no decking issues. Total: $8,100. This is what the bottom of the range looks like: small, simple, and single story.
If your quotes don’t itemize like these do, ask for the breakdown in writing before you sign anything.
Tear-Off or Overlay
An overlay installs new shingles directly over the old layer and saves $1,000 to $2,500 on an average roof. It’s legal in many places, and it’s usually a mistake you pay for later.
Three problems, one of which matters most: the crew can’t inspect decking that stays buried, so rot and rusted nails stay hidden under a brand-new surface. The extra layer also holds attic heat against the new shingles and shortens their life. And the next roofer tears off two layers, which costs more than one proper tear-off would have today. Most manufacturers limit or void warranty terms on second-layer installs too. An overlay makes sense in one situation only: a sound single layer, a short holding period, and a buyer who knows exactly what’s overhead.
The Decking Surprise
The line item homeowners never see coming is decking. Nobody knows what the wood looks like until the shingles come off, so good contractors quote a per-sheet price, typically $90 to $150 per 4x8 sheet installed, and call you with a count if they find rot.
On a 20-square roof, six bad sheets is a $540 to $900 add-on. Eighteen bad sheets, which happens on older roofs with long-running leaks, pushes past $2,000. You can’t eliminate this risk, but you can force it into the open before signing: get the per-sheet price in writing, and ask what happens if the crew finds more than ten sheets. Some contractors cap the exposure, some call with photos. One just invoices you afterward, and that’s the one to avoid.
Ventilation: The Part That Gets Skipped
A shingle roof needs intake air at the soffits and exhaust at or near the ridge. Without it, attic heat bakes the shingles from below and winter moisture condenses on the underside of the deck. Both problems show up later as premature failure, and both make warranty claims the manufacturer will deny.
Fixing or adding ventilation on an average roof runs $500 to $1,500, and skipping it to shave a quote is the classic false economy in roofing. Check that any quote itemizes soffit intake and not just ridge vents. Exhaust without intake pulls conditioned air up through your ceiling instead of pulling outdoor air through the attic, which raises your energy bills while the attic stays hot anyway.
How to Pay Less
- Buy in the shoulder seasons. Early spring and late fall book slower in most markets, and contractors with open crews commonly discount 5 to 15 percent to keep them full. In hail states, the weeks after a big storm are the worst time to buy: every crew is triple-booked and prices know it.
- Get three itemized quotes in the same week. Identical specs came back $4,000 apart on a job we priced in Columbus. The expensive bid wasn’t better shingles, it was overhead and a slow schedule.
- Buy the mid-tier shingle, not the flagship. Most manufacturers’ mid-level architectural lines carry the same wind ratings as flagships; the premium mostly buys a longer non-prorated warranty period, not a better shingle.
- Confirm you actually need a full replacement. Isolated damage on a younger roof often qualifies for repair, which we cover in roof repair vs. replace.
Mistakes That Cost Homeowners Money
- Signing a quote without a per-sheet decking price. This is the single most common roofing upcharge dispute we hear about.
- Taking the cheapest bid without proof of insurance. Ask for the liability certificate itself. An injured worker on your property without coverage is legally your problem in many states.
- Paying flagship prices for “lifetime” branding. Lifetime shingle warranties are prorated, labor is covered only briefly, and the fine print excludes ventilation and installation errors. Read the panel warranty, not the brochure.
- Letting the crew skip the permit. Unpermitted reroofs surface at resale and can complicate insurance claims after storm damage. The $200 saved isn’t worth it.
Run every quote past our contractor red flags checklist before signing. If you’re weighing metal instead, the full comparison lives in metal roof vs. shingles, and the reasoning behind our price ranges is explained in how we estimate costs.
Bottom Line
Budget $450 to $750 per square installed, multiply honestly by your roof’s real square count including pitch, and hold back $500 to $1,500 for decking surprises. Spend on tear-off, underlayment, and ventilation rather than flagship shingles, get three itemized quotes in the same week, and never let anyone bury a second layer on a roof you plan to keep.
FAQ
How many squares is my roof?
Multiply your home’s footprint by the pitch factor (1.05 at 4/12, 1.12 at 6/12, 1.20 at 8/12, 1.41 at 12/12), then add about 5 percent for overhangs. A 1,600 sq ft single-story home at 6/12 works out to roughly 19 squares. Every quote should state its square count, and all of them should agree with each other.
How long does an asphalt roof replacement take?
One to three days for most homes. A walkable single-story roof with one layer to remove is a one-day job for a full crew. Steep two-story roofs, two layers of old shingles, or heavy decking repair stretch it to two or three days, and the town inspection happens separately afterward.
Can I put new shingles over my old roof?
Usually technically yes, and usually practically no. Most codes allow one overlay, but you lose the decking inspection, risk shorter shingle life from trapped heat, and pay double tear-off next time. We’d only do it on a sound single layer as a short-term fix on a home you’re selling soon.
Does insurance pay for a roof replacement?
Only for sudden damage like hail, wind, or a fallen limb, and policies increasingly apply age limits or pay depreciated actual-cash-value instead of full replacement cost. Gradual wear is never covered. If a storm hit your area, get the roof inspected and file promptly, because claim deadlines are short.