What You Need to Know About Ice Dam Removal on Slate Roofs
Why? Because slate roofs are extremely fragile. You might think your slate roof is bullet-proof because it’s made out of stone, but that’s not really how it works. The slate on your roof is similar to the stone our ancestors used to make arrowheads. It’s not at all similar to the stone our ancestors used to make the Pyramids!
A novice ice dam professional might not even know this. He’ll get up there and swagger around on your roof like he’s John Wayne. Unless he also happens to be professional slate roof contractor, your tiles will be snapping, crackling, and popping! The neighborhood kids will come running over because they think you’ve got some of that fun bubble wrap.
We’ve seen it happen. In Massachusetts we had a customer who owned a gorgeous historic Colonial with a slate roof. He hired one company to do the snow removal, and then he hired us to remove his ice dams. We watched (and listened!) in horror as this other company crunched up practically every tile on his roof. We called him and tried to warn him that his roof was getting destroyed, but he decided he’d just get it all fixed in the spring.
Fortunately for a roof-repair company in Massachusetts, he had the kind of money that he could afford to fix his snap-crackle-n’-pop roof. Most homeowners don’t, though. Although we didn’t see a money tree on his property, evidently there must have been several that escaped our view. We’d guessed that snow removal company caused a solid 75K in damaged slate tiles! Ugh.
Highly skilled pros can sneak cat-like across a slate roof, taking the shortest route to their destination. Some of our most experienced ice dam professionals can do it, but we try to stay off slate roofs unless there’s no other way. Even then, we ask the homeowner’s express permission and make sure they understand that no matter how careful we are, there’s a very real chance that something will go “crunch!”
In most cases, we just bring our ladders and get ready to work, but even that has its hazards. You have to be careful where you place the ladder. For example, if the roof doesn’t have any gutters (slate roofs often don’t), you can’t just lean the ladder against the roof. If those tiles hang over the fascia even a little bit they’ll crack as soon as any weight is put against the ladder.
Instead, we carefully lean the ladder against the ice dam itself. Then we might steam to our right side as we move left down the overhang. When we get to the very end of the ice dam we move the ladder on a clean, dry shingle that’s less prone to cracking, set it almost vertically so that there’s less pressure against the very edge of the roof as we climb up the ladder, and we quickly steam off the last of the ice dam.
We also have to do all of this at the correct temperature, because if our steam is too hot the heat itself will fracture the slate. It’s like pouring boiling water into a cold glass. It can shatter.
You also have to make sure you’re paying attention to the architecture itself. Ice doesn’t grip a slate roof quite as well as it grips an asphalt roof. It’s possible that you go up and just start blasting the ice dam like it owes you money, the ice may fall and take a big chunk of the slate roof with it.
That’s why we create channels in the ice to either side of the ladder, and then create a perforated edge, just like the edge you might find in a notebook that allows you to tear out sheets of paper. With a little luck and a lot of skill, the ice will break away on this edge. We help luck along by steaming in small, 1-3 -foot sections to make it easier for the ice to break where and how we want it to.
A novice might jump up there and start steaming away. A novice will just rest his ladder against the roof. A novice might be professional, ethical, well-meaning prince of a guy, but you still don’t want to your roof to be his lesson. Slate roofs require extremely experienced ice dam professionals who have been in the business long enough to get the ice off of your slate roof without destroying it.
If you have a slate roof, make absolutely sure you pay attention to my guide to hiring the right ice dam professional before you call and make an appointment with any provider.