Can You Install Metal Roofing Over a Shingle Roof?
In almost every case, the answer is yes, you can lay down a new metal roof over an existing shingle roof. This is one of the many reasons metal roofs keep growing in popularity – their installation doesn’t require completely tearing off the existing roof, which is a time-consuming and expensive job.
Metal, although super-strong, is very light, weighing less than a pound per square foot compared with as much as four pounds per square foot for asphalt shingles. Adding a metal roof over existing shingles doesn’t significantly increase the overall load for the home structure to bear.
Along with saving the cost of completely removing the existing roof, installing a new metal roof over a current roof also brings the benefit of additional insulation above your home to prevent heat and cool from escaping.
And since we mentioned insulation, we should also mention that metal roofs are heat-blockers – they reflect heat away from their surfaces rather than absorb it. This means the extra insulation from your shingle roof will not act as a heat trap for heat emanating through your metal roof.
Factors to consider when installing a metal roof over shingles
- What we said above about installing metal over shingles is true in the majority of cases. But it’s always best to check with your local building and zoning departments to make sure they approve metal-over-shingle installations.
- If your shingle roof has leaks, you’ll need to inspect for rotting rafters or sheeting. These problems should be fixed before installing the new roof.
- If the current roof’s weight has caused structural problems like buckled trusses or decking that is sagging, these issues need to be addressed before new installation begins.
- It’s usually a good idea to consider adding some type of underlayment on top of the shingles to prevent their granules from contacting the metal and leading to corrosion. Your metal roofing contractor will tell you about options for this.
Benefits of sturdy metal roofs
When you install your new metal roof over an existing shingle roof, you immediately save money that normally would be spent to have the old roof torn off. But this is just one of many benefits of a metal roof. Here are four more:
1. Long life: A properly installed metal roof should last for 40 or 50 years or more before a replacement is needed.
2. Virtually impervious to damage: Metal roofs hold up in the most intense weather events from pounding hail and ice storms to gale-force winds and searing summer heat.
3. Very low maintenance: Because of their strength, metal roofs won’t require regular, expensive repair jobs. Year after year, decade after decade, they retain their soundness.
4. Lowered cooling bills: As noted above, special coatings on metal roofs allow them to reflect and block heat rather than absorb it. This results in cooler interior temperatures in the summer and less need to use your AC system.
If you’d like to know more about metal roof installation or metal roofing in general, contact the experts, Advanced Aluminum of Lakeland, FL. We manufacture top-grade metal roofing products used by leading contractors across the Lakeland region. Reach us with questions at (863) 648-5787.