Yes, a shingle roof can be replaced in winter. On any given day, two things decide it: the shingles need to be warm enough to bend without cracking, and the roof has to be free of ice and frost. If yours is simply getting old, you can plan the job for milder weather instead, as our guide to the best time of year to replace a roof explains. If it’s leaking, don’t hold off until spring.
What the cold changes on the day of the job
Cold shingles are stiff, and a stiff shingle can crack where it gets bent. On a roof, that means the ridge along the top, the hips at the corners, and the valleys, where one slope meets another. Shingle makers’ cold-weather advice is to warm the shingles before they go on in those places, and to keep the bundles somewhere heated until they’re needed. Throw or drop a bundle in the cold and the shingles inside can crack.
Cold bundles also tend to hold the shape of whatever they were stacked on. Each shingle has to lie flat before it’s nailed, or the nail can break through it.
The roof itself has to be ready too. A film of frost on the deck or the underlayment is hard to see, especially on an overcast day, and it turns a sloped roof into a hazard. The makers want it gone before anyone works up there, and one of them tells installers to follow the sun in cold weather, working wherever it’s shining. A winter replacement depends on the forecast more than on the calendar.
Why a new roof may not seal right away
Most shingles leave the factory with a strip of sealant on them. Once the sun warms it, it bonds each shingle to the one underneath. In January there may not be enough warmth to do it. Shingles put on in the cold may not seal until warmer temperatures arrive, and may take longer to lie flat.
Which way the roof faces makes a difference. Slopes facing south or west typically seal faster than slopes facing north or east, and very steep slopes take longer than shallower ones. On a roof put on in January, the north and east slopes are usually the ones that wait.
Wind gets under an unsealed shingle more easily. For that reason the makers recommend sealing shingles by hand when it’s cold, with a few dabs of asphalt roof cement pressed in under each one, following the instructions for that shingle. Not too much, though. Too much cement can make the shingles blister.
If you’re having a roof replaced in winter, ask how the shingles will be kept warm and how they’ll be sealed.
A leak in January
A leak found in January needs fixing in January. Lehigh Valley winters freeze and thaw a roof over and over, and each thaw sends more water through the same gap, into the wood and the insulation underneath. The damage spreads while you wait.
A repair follows the same cold-weather rules as a new roof, on a smaller patch. Cold shingles, above all ones that don’t lie flat, can crack underfoot, and footsteps can break the sealant bond from one course to the next. So the shingles around a repair may need sealing by hand as well.
Not every winter leak is a hole in the shingles. If water comes through after snow has sat on the roof for a while, and there’s a ridge of ice along the gutter, the cause may be an ice dam. Meltwater pools behind the ice at the eaves and works its way in under the shingles. Fixing that for good means looking in the attic, where the heat that melts the snow gets in.
Until a roofer has been out, stay off the roof. If the snow has to come down, use a roof rake and keep your feet on the ground. Shovels, scrapers and footsteps on the roof can all damage the shingles. Indoors, catch the drip in a bucket and clear what you can from under it.
Getting a roof ready before the snow
Cold weather goes to work on the gaps a roof already has, like sealant that’s split around a vent pipe or flashing coming away at the chimney. Each one is easier to deal with in the fall, while the shingles still bend and the roof is dry, than in the middle of January. What we look at in a fall inspection, and what you can look for without a ladder, are in our winter roof inspection guide.
Replace now, or wait for spring?
If the whole roof is worn out, and it’s leaking in several places, losing shingles in patches or starting to sag, patching it through the winter usually just buys time. Waiting for spring gives the water longer to spread into the decking. When the trouble is in one spot and the rest of the roof is sound, it’s usually a repair now and a replacement when the roof is due. Our repair-or-replace guide sets out how to tell which you have.
Whenever the roof is replaced, that’s the chance to protect the eaves against ice dams. The Asphalt Roofing Manufacturers Association recommends a self-adhering underlayment along the eaves wherever ice dams are a risk, to guard against water backing up behind the ice. Our post on ice and water shield shows where it goes. Ask for it to be spelled out in the estimate.
Estimates are free, for a repair to something you can see and for a whole new roof. Call (484) 553-0213 about a stain that’s spreading across a ceiling, or a roof you’d rather not take into another winter. You can also write to us through the contact page.