How To Install Metal Roofing Over Shingles
Can you install metal roofing over shingles? This is a question many roofers get asked often. And the answer is that it is not just possible – it is indeed desirable for many reasons. There are benefits to having a metal roof over shingles. You don’t have to tear down the old leaky roof, which itself saves you labor costs and the trouble of disposing off the waste. Another advantage is that the extra layer provides added insulation to your home.
To install metal roofing over shingles, your rationale might be that metal roofs are lighter and don’t need modifications to the frame of your older roof. Metal roofing materials weight just a quarter of what the heavier asphalt shingle roofs do, and this has benefits. In some places the regulatory guidelines specify that such roofing over shingles can only be permitted when there is a single layer of shingles in the older roof, and the new roof will be a metal one.
What’s important to note is that when your new roof will support the entire load of the expansion through transmitting it directly to the earth, and doesn’t need to rely upon the older roof for this support, you will not be compelled to tear down the older one. A standing seam roof fits this requirement, which is why it is a good choice for metal roofing over shingles.
Once you’ve decided to install new metal roofing over shingles, it’s time to first make some preparations before going ahead. You need to patch any damaged areas and repair leaks first. Broken or rotten frame or shingles must be replaced. By doing it sooner, you can avoid the need for more expensive repairs later one. Very heavy roofing materials might be profitably removed because by doing so you will reduce the overall weight of your roof.
Another way to workaround this is to make the roof frame stronger by inserting one additional layer of underlayment, or reinforcing the existing frame. Tar paper is a common choice for this, but it bears remembering that it could melt and stick to the undersurface of the new metal roofing over shingles, causing problems. Bubble wrap and other synthetic material make for better underlayment choices.