Did you know that everything expands and contracts? Including your roof! If your roofer doesn’t take that into account when he’s installing your roof, it could cause some big problems.
As things heat up, they expand, and as they cool down, they shrink. Have you ever noticed the lines in a concrete sidewalk? Those are called expansion joints. Without them, sidewalks would crack and move. You have expansion joints in almost everything.
Your roof does the same thing. Many homeowners think we can just take off their old roof, and put on a new one. Well, it’s not quite that easy. Remember the plywood deck we’ve talked about? You have to leave a gap for that plywood to expand and contract. A lot of roofers miss that part. Two years later, the plywood gets too close together and it pops. You get that strange-looking bubble on your roof.
There are other things that can expand and contract on the roof. Did you know your chimney and roof are not actually connected? They appear connected by caulking and flashing. The brick on the chimney expands and contracts at a slower rate than your roof; the two pieces move separately. So we have to install two different pieces of flashing to allow them to move. Many roofers don’t address that flashing correctly.
We see it with wood shakes when the shake has a curl to it. The roofer decides to push it down with a staple. That’s never going to hold. Five to seven years later, that shake is pulled completely out. That’s the wood going back to its original memory.
So expansion and contraction on a roof is huge. Does your roofer do the right thing to combat that? Some of them are relatively easy fixes. A plywood pop is a little more difficult, because to correct that we have to pull the shingles, get down to the plywood, re-gap it, screw it in place, and put on new shingles. The downside is, after a few years, the shingles aren’t going to match.