Re-roofing or Layover: An Alternative to Complete Roof Replacement?
What is a Layover in Roofing?
How much if any of the felt underlayment is covering the decking and is the decking itself dry?
When Not to Opt for a Layover
When Is Roof Replacement a Better Option Than Overlay?
The best thing about a complete roof replacement rather than doing a layover is that it can be done at any time. Total replacement should always be the default option when you have more than one layer of shingles on your home’s roof. It is also highly recommended when you suspect the decking to be the main problem with the roof rather than the shingles. If the shingles on your roof are in bad shape, the more likely scenario is that the decking underneath it is in poor shape as well and is in dire need of inspection and repair rather than being covered up.
Why Should You Reject Layover?
- Decking Problems Left Unsolved: Covering up the existing shingles with another layer of shingles temporarily covers up an existing problem with your roof’s decking and lets them fester for future problems to occur with your roofing.
- No Ice and Water Shield: Tearing off the existing roof allows the roofing crews to install or repair secondary leak protection like an ‘Ice and Water Shield.’ Any secondary leak protection needs to be installed on the decking to work properly. Without secondary protection, ice and water can sneak below the top layer of shingles and get trapped in the old layer causing all kinds of leaks and other problems.
- Roof Collapse Hazard: The weight of a single layer of shingles can be as much as 250-300 pounds per 100 square feet of decking. By having a layover you are doubling that weight to roughly 500 pounds. If you have rotting or soggy decking under it, it means that during inclement weather and with additional water and ice snuck under the top layer you are risking the roof collapsing during a rough storm during inclement weather.
- Lower Life Expectancy: If you do not resolve the issues underlying your existing roof shingles, it will detract the new layer of layover from protecting your roof for the long term that the new shingles are rated for. If the new shingles are a poor fit, it will allow ice and water to sneak under them and cause all sorts of havoc needing both layers of shingles to be removed before the investment of the layover is realized.
In conclusion, a layover might be a good option for a roof that has no major issues with leaks or rotten or soggy decking. However, it is impossible to know this for certain without removing the old shingles, and homeowners who choose to do a layover without knowing the problems lurking underneath get a rude awakening when those problems crop up after the layover has been done. Your best option is to tear off your existing roof and have a new roof put on after a thorough examination and eradication of underlying problems.