For an asphalt shingle roof, the best time to replace it is a stretch of mild, dry days. Shingles go on most easily when it’s neither cold nor very hot, and in the Lehigh Valley that weather comes mostly in late spring and early fall. A roof can still be replaced in other months. One that’s already letting water in shouldn’t sit waiting for a better season.
Cold weather and the seal on each shingle
Asphalt shingles stiffen as the temperature drops. Bent or dropped in the cold, they can crack, or in a bad case break apart. That’s why the Asphalt Roofing Manufacturers Association (ARMA) tells installers to work at a temperature where the shingles are still flexible and to follow each maker’s cold-weather instructions.
The seal is the part you can’t see. Most shingles carry a strip of asphalt sealant that bonds each one to the course below once it has had enough heat. How long that takes depends on the pitch of the roof, which way it faces and how much sun it gets. Until it seals, a shingle is held by its nails alone, and wind can lift it more easily. In very cold weather, shingles can be sealed by hand with roofing cement to guard against blow-off.
Then there’s ice. Frost or ice on a roof deck can be close to invisible, and ARMA’s advice is to wait until the surface is clear of both. So whether a winter replacement goes ahead comes down to the day. Our post on a winter roof replacement goes into it.
Summer heat and soft shingles
Heat brings the opposite problem. On a hot, sunny day the asphalt coating on the shingles softens, and new shingles scuff underfoot more easily, above all on steep slopes and in the valleys, where installers walk most. The same sun seals them once they’re down. Summer works. It takes more care on the roof.
Can a roof be replaced in the rain?
Not while it’s raining. With the old shingles stripped, the wood deck underneath is open to the weather, and decking that takes on rain or dew during a roof replacement can soak up the water and move. That movement can show through the new roof as shingles buckling along the joints in the deck. Underlayment that gets wet can wrinkle under the shingles too.
So the work needs a dry spell, and a roof that’s been opened up needs covering before rain comes. If rain is forecast for the week of your job, ask how any open part of the roof will be covered.
When a roof shouldn’t wait for good weather
Picking a season only makes sense when the roof can wait. If water is coming through a ceiling, shingles are missing after a storm, or part of the roof has started to sag, call now, whatever the month. Every rain until then puts more water into the decking and the insulation.
Calling now doesn’t always mean a new roof now. Damage in one area of a roof that’s otherwise sound can be fixed with a roof repair, and the replacement can wait until the whole roof is due. Wear all over the roof, or the same leak returning after it’s been repaired, is when to start planning the roof replacement.
Planning ahead is also what lets you choose the weather. Age is one reason to start, and our post on a shingle roof’s lifespan in Pennsylvania covers what to expect. Curled or cracked shingles, bald areas that have lost their granules, and grit piling up in the gutters all point the same way.
What to sort out before the work starts
A few things are worth settling while you’re still choosing a date.
- Rotten decking. Soft or rotted boards often don’t show until the old shingles come off, and what turns up underneath can change the price, so ask how the estimate deals with it.
- Attic ventilation. A new roof is the time to make sure air comes in at the eaves and goes out near the ridge. ARMA ties poor attic ventilation to the same deck movement that wet weather causes, and our guide to summer roof leaks explains what a hot, closed-up attic does to the roof.
- A permit. Ask whether your city, borough or township requires one for the job, and who will apply for it.
- The price in writing, before you sign. What goes into it, from the roof’s size and pitch to tear-off and disposal, is set out in our Pennsylvania roof cost guide.
Closer to the day, the house needs some getting ready too, from the driveway to the attic, and our post on preparing for a new roof takes you through it.
When you want a price for the new roof, we’ll look the roof over with you and write up an estimate at no charge. Our number is (484) 553-0213, and the estimate form is on our contact page.