I recently saw my neighbor getting a steel roof put on her lovely 2500 sq ft home from the 1990s. The roofing company installed furring strips on top of her existing asphalt shingles, and I'm curious about why they didn't do a tear-off first. The contractor claimed it was for better insulation, but that doesn't seem right. Worst of all, the crew seemed unprofessional and was working without safety gear in bad weather! She paid over $30k, and I can't help but think this might not have been the best decision. For those experienced in roofing, does leaving shingles under a metal roof actually benefit insulation or is there more to it?
3 Answers
I've seen quite a few installations where they leave the existing shingles underneath, and it can be for a few reasons. One, it makes the install quicker—less time spent tearing off and dealing with potential rain delays. Two, asphalt shingles can help reduce noise from rain hitting the metal roof. Plus, it saves on disposal costs for the old shingles! But do check the manufacturer's guidelines; they usually clarify what's acceptable as it can vary by brand and local building codes. It's not a straight-up answer, though; the condition of the old shingles matters too. If they're in rough shape, that's definitely a different story!
Totally get your concerns—especially with the workers' safety up on that pitched roof! Leaving the asphalt shingles can actually cause moisture issues and might not pass code, depending on where you live. Always worth doing a thorough inspection of the decking before putting new roofing on. That said, in some cases, they might leave the old layer on just for ease of installation if everything’s up to code. Code compliance is key, though, so definitely check with local regulations about this. Safety first!
While I'm not a roofer, I can share that it’s generally not best practice to install over old shingles without checking their condition and the roofing codes in your area. Leaving the shingles could trap moisture, which may create problems later on. It just boggles my mind how they could inspect everything properly without a proper tear-off. Always good to know what your local building codes say; they’re there for a reason!