Should I Repair or Replace My Roof?

Short answerRepair usually fits a localized problem on a roof with years left, while widespread damage or a roof near the end of its life points to replacement. NAHB's 2007 study puts asphalt shingles at about 20 years. For slate, the National Park Service says that at 20% or more damage, replacing usually costs less.

What each option costs

Our national estimates, not quotes.
Option	Job	Low	High
Repair	Roof Repair	$180	$1,550
Replace	Roof Replacement	$6,650	$20,800

Questions to answer first

Ask a roofer to show you the answers, ideally with photos.

How old is the roof, compared with the expected life of its material?
Is the damage in one spot or across the roof?
How many layers of shingles are on it now?
Is the roof deck underneath damaged?

The 20% test, and where it applies

The National Park Service says slate repair works for localized problems on roofs with a reasonably long life remaining, and that once 20% or more of the slates are damaged, it is usually less expensive to replace. That figure is about slate only. We couldn't confirm an equivalent official number for asphalt shingles, so ask for a written assessment.

Layers can decide it

FHA appraisal guidance, archived November 2, 2012 and written for FHA-insured homes, said that if more than two layers exist and repair is needed, the old roofing must be removed. We did not confirm current FHA rules. Portland, Oregon allows a maximum of two layers. Local rules differ, so check with your building department.

Don't forget insurance

The Insurance Information Institute says insurers may limit coverage on an older roof to actual cash value, and that most require an inspection on a roof over 20 years old when you apply. Use the cost comparison on this page to set a repair estimate against a replacement estimate for your area.

Roof Leak? What to Do Now and When to Call a Roofer

Common questions

Can I just replace the bad shingles?

For a localized problem on a roof in good condition, usually yes. NC State Extension suggests checking for curled, damaged, loose or missing shingles. If those are spread across the roof, a patch may not hold up for long, so get a roofer's opinion.

Can I put new shingles over old ones?

It depends on local code and how many layers are already there. Portland allows a maximum of two layers, for example, and archived FHA guidance had its own limits. Ask your building department and roofer.