One of the biggest questions homeowners have when they start thinking about replacing their roof is whether or not they can install the new roof over the existing one. This question especially arises when the homeowner plans on replacing a shingled roof with a metal roof. So, can you put metal panels over shingles?
Do You Have to Remove Shingles Before Installing a Metal Roof?
Although the answer is technically no, you don’t have to remove the old roof, Bridger Steel’s team NEVER recommends installing a new metal roof directly over an old roof. This is because by installing the new roof over the old one, you can easily miss any damages, water spots, mold, or rot that may be underneath the old singles or materials, which can cause future damage. It can also result in having to remove the new metal roof a few years down the road to fix the underlying problems from the old shingles or underlayment, causing extra and easily avoidable work. Installing a new metal roof over an old shingled roof also affects Bridger Steel’s warranties because the abrasions from the “rocks” on shingles can cause backside wear as the metal expands and contracts from both hot and cold weather.
Installing a metal roof over shingles can also result in an increased chance of trapped water vapor and moisture between the new roof and old roof, resulting in new mold and rot. By removing the old roof before the new roof’s installation, you are able to give the underlayment a thorough inspection to ensure there are no damages that could cause leaks or other issues with your new roof. Not only should you inspect the underlayment outside, but you should walk through the attic if possible to inspect the area for any potential leaks, rotten rafters or sheets, and any other potential problems. It also allows you to be on the lookout for any signs that the previous roof’s weight caused damages like buckling tresses or sagging decking.
Both of these careful inspections will give you the reassurance that once you’ve installed your new metal roof, no prior damages will affect your new roof’s performance. Although removing shingles may be messy and take a bit more time, the end results and confidence in knowing your metal roof will last for decades to come are worth it!
If You Install Metal Over Shingles
If you do decide to install your new metal roof over your old shingles, be sure to consult local building codes. Some jurisdictions require a full and complete tear-off whenever a new roof is being installed. Others also don’t allow more than one layer of shingles to be reroofed according to Section 1511.3.1 of the 2018 International Building Code (International Code Council Series) 1st Edition.
You’ll also want to be sure you choose a lighter metal material to ensure you don’t cause extra stress on your home that can potentially be damaging to the tresses, decking, and even the foundation. Choose a material like steel or aluminum, which are lighter metal materials, rather than heavier material like copper. Metal roofs are much lighter than shingles, so they are able to be installed over an existing roof. However, once again, our team never recommends doing so.
If you have any questions about metal roof installation, reach out to one of our Product Specialists today. Our team will work directly with you in order to meet your project’s specific requirements. We’ll help you choose the right panel profile, gauge, and color or finish to create the roof your home needs.
If you’re planning on installing your new metal roof yourself, we have installation guides for most of our metal panels. You should still consult with a Product Specialist before proceeding with installation in case there are any new changes you should be aware of.