Things To Know Before Replacing Asphalt Roofs With Metal

Replacing your old asphalt shingle roof with a metal roof can be a great idea, especially if you want a low-maintenance and long-lasting roofing option.

Slope and Structure Assessment

Slope impacts metal roofing. Metal is not installed on flat or nearly-flat roofs because there needs to be some slope to ensure water and snow drainage. If your home has a very low-sloped roof, it may require a rebuild of the truss structures in order to increase the slope.

The basic structural integrity of the roof must also be assessed. The good news is that metal roofing panels often weigh less than a traditional asphalt roof, so it is likely that the weight specifications for your roof will be sufficient unless you plan to add other structures, such as solar panels, to the roof after installation. Trusses and support systems will be inspected for signs of rot. There may also be a need to install hurricane strapping and other fasteners to guard against roof blow-offs.

Ventilation and Insulation Planning

Ventilation and insulation requirements may change if you are replacing an old shingle roof with a metal roof. Metal roofs don't breathe as easily as shingles, so extra ventilation may be necessary, such as longer ridge vents or additional mid-roof vents. The goal is to keep air flowing through the attic so condensation doesn't develop.

The insulation quality of plain metal panels can also be lower compared to layers of asphalt shingles. There are insulated metal panels available, which can be more effective than the old shingles. You may also need to increase insulation levels in the attic itself to counteract the lower insulation value of standard uninsulated metal panels.

Decking Inspection

The roof decking is the plywood that covers the trusses and that the shingles or metal panels attach to. If the decking is damaged or rotten, it must be replaced before the metal roof can be installed. It's important that decking is in excellent condition since a metal roof has a lifespan measured in decades.

If the decking is in good condition and there is no major damage to the shingles, you may be offered the option to have the metal panels installed directly over the old asphalt roofing. This will save money and time since the tear-off of the old roof won't be a necessary expense.

For more information about roof replacement, contact a local company that offers this service, like iHome designs.


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