In nearly all cases, YES, it is possible to install a new metal roof layer over a current shingle roof. That is a valid reason why it is increasing in popularity. Its application doesn’t require the entire detachment of your current roof, which is often costly and time-consuming.
Metal, although pretty robust and solid is quite lightweight, weighing less than 1 pound/sq.ft. It’s almost 4X less heavy compared to asphalt shingles which weigh 4 pounds/sq.ft. Plus, adding a metal roof over current shingles doesn’t remarkably raise the total burden that the home’s structure needs to hold.
Besides leading to cost savings (as it doesn’t need the entire detachment of the current roof), the installation of a new metal roof on top of an existing one also provides extra insulation over your house to stop the escape of heat and humidity.
When it comes to insulation, it’s noteworthy to mention that metal roofs are blockers of heat. They block and repel heat away from their exterior instead of absorbing it. That means the additional insulation layer will not serve as a heat blocker for heat emittance through your metal roofing.
Important Considerations When Applying A Metal Roof Above Shingles
What we have previously mentioned about the application of metal above shingles applies to most roofing procedures. However, if you are unsure, it’s best to consult your local construction and zoning authorities to ensure that metal-over-shingle applications are acceptable.
In case your shingle roof shows leakage, you’ll have to check it for decayed rafters or sheets. These issues should be resolved immediately before the application of the new roofing.
In case the existing roof’s burden has led to structural issues e.g. decking, these problems have to be tackled before the beginning of the new roof application.
It’s also typically a great idea to add some kind of underlayer over the shingles to prevent their granules from touching the metal and result in damage. You may ask your roofing expert for more info on suitable options for your case.
Advantages of solid metal roofs
Once you set up your new metal roof over a current shingle one, you will instantly save some cash that would otherwise be spared to detach an existing roof entirely. But, this isn’t the only benefit of a metal roof. Here are 4 other benefits:
- Longevity. A rightly applied metal roof can last up to 50 years before it needs replacement.
- High resistance to damage. Metal roofs can tolerate most extreme weather conditions such as heavy winds, rainfall, or ice and hail storms.
- Minimal maintenance. Due to their strength, metal roofs won’t need frequent and often costly fixing work. They can keep their strength through several years.
- Lower utility charges. As mentioned previously, special layerings on metal roofs enable to repel heat instead of absorbing it. This leads to less reliance on AC units to cool down interior temperatures during the hot summer season.