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Roofing · Replace or repair
Roof replacement
Replace when the shingles are curling generally, when there are already multiple layers, or when the decking is compromised. Age alone is not the test. And whatever you are told about the decking belongs in the quote, not in a change order.
A roof replacement is one of the bigger checks a homeowner writes, and most of the surprises come from what is under the shingles. The way to avoid them is to know what should be in the quote before the old roof comes off. On older houses that especially means the decking.
1When replacement is the right call
| What you see | Usually means |
|---|---|
| Curling or cupping across most slopes | The shingle has reached the end of its life. Replace. |
| Curling in one area only | Often a local ventilation or install problem. Repair may do. |
| Two or three layers already | No room for another overlay. Tear-off and replace. |
| Soft or sagging decking | The structure under the shingle is compromised. Replace, including the decking. |
| A few missing or damaged shingles on a sound roof | Repair. |
| Old, but flat, sealed and shedding water | Age alone isn’t the test. Keep it and keep watching. |
Repair or replace a roofHow old is your roof?Roof age by shingle type
2Tear-off or overlay
Overlay
- New shingles nailed over the old layer
- Lower labor and disposal cost
- Hides the decking, so problems stay hidden
- Adds weight; the number of layers allowed is limited, so check local code
- Most manufacturers won’t warrant it
Tear-off
- Old shingles removed down to the deck
- Costs more than an overlay
- Lets the roofer inspect and fix the decking
- New underlayment, flashing and drip edge go on clean
- The only version most manufacturers will warrant
If your roof already has two or three layers, an overlay is off the table. See two or three layers of shingle already on the roof.
3Decking: where the surprises are
On pre-1970 houses, expect plank decking: boards with gaps between them rather than sheets of plywood or OSB. Modern shingles generally need a solid deck, so plank decking usually has to be overlaid with new sheathing. Some older roofs also have wood shingle under the asphalt, which has to come off.
That work belongs in the quote, not in a change order once the old roof is off. Ask for:
- A decking line itemEither a full re-sheathing price, or a per-sheet price for replacing damaged sheets.
- An allowance in writingHow many sheets are included before extra charges start, and the price for each one after.
- Photos before it’s coveredAsk the crew to photograph any decking they replace, so you can see what you paid for.
Plank decking with gapsWood shingle under the asphaltSagging along the ridge
4What a complete quote covers
- Tear-off and disposal, including how many layers.
- Decking, priced as above.
- Underlayment and ice barrier where local code or the manufacturer requires it.
- Drip edge at the eaves and rakes.
- Flashing: whether chimney, wall and valley flashing is replaced or reused. Rusted valley metal and chimney flashing should be replaced, not reused.
- Ventilation: ridge vent and soffit intake. A new roof over a poorly vented attic ages early.
- Pipe boots and vents, the permit, cleanup, and both the manufacturer and workmanship warranties.
Valley metal rusted or missingRust streaks below the chimney flashingMasonry chimney needs workNo ridge vent and no soffit intake
If the masonry chimney needs work, have it done before the new roof goes on. Otherwise the new flashing gets torn out later.
5Choosing the material
Most replacements are architectural asphalt shingle. Metal costs more up front and lasts longer. In hail country, impact-resistant shingle may earn an insurance discount; ask your insurer for their figure before you choose the product.
Asphalt shingle vs metal roofImpact-resistant shingle and the insurance discount
6What drives the cost
| Factor | Why it moves the price |
|---|---|
| Roof size and pitch | Steep roofs need more safety setup and go slower |
| Layers to remove | Each layer adds labor and disposal |
| Decking | Plank decking or rot means new sheathing |
| Material | Three-tab, architectural, impact-resistant and metal are priced very differently |
| Flashing, chimney and vents | Penetrations and intersections take time to flash correctly |
| Ventilation upgrades | Adding ridge vent and soffit intake adds a line item |
Talk to a local roofer who will price the decking up front instead of after the tear-off.
877-360-46577Questions
My roof is 20 years old. Do I need to replace it?
Not because of the number alone. If it is flat, sealed and shedding water, keep watching it. Replace when it is curling generally, losing granules heavily, or the decking is failing.
Can I just put a new layer over the old one?
Sometimes, if there is only one layer and local code allows it. But most manufacturers won’t warrant an overlay, and you can’t see the decking.
Why did my roofer charge extra for decking?
Because damaged or plank decking was found at tear-off. Ask for the decking price in the quote next time, as a per-sheet price or an allowance.
Will insurance pay for a replacement?
Only for covered damage, such as hail or wind, not for age or wear. See insurance claim after hail.
Written by Jaylan Jones. I Like To Exterior Services earns a referral fee when a call connects to a contractor. See our business-model disclosure.
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