The answer is yes, you can lay new roof shingles over old ones. You can't do it with wood or slate, for example, and you should never mix materials, such as laying asphalt shingles over cedar shakes. Also, the old roofing has to be in pretty good condition. Otherwise you're just putting lipstick on a pig.
At what age should a roof be replaced?
Your asphalt roof is about 20 years old For a standard 3-tab asphalt shingle roof, that's 25-years. As long as your roof has been properly ventilated and installed you should get pretty close to that 25 years of roof life. So obviously you want to replace your roof before it starts leaking or fails completely.12 May 2020
Should you remove old shingles before installing new shingles?
While a repair job can often be more convenient and somewhat more cost-efficient, placing new shingles over old ones is never a good idea. Whether repairing one section of roof, or a replacing a whole one, it's always best to pull up the old shingles before putting down the new ones.11 Jul 2017
Should I remove old shingles before installing metal roof?
Metal roofs can be installed over your existing roof without tearing off shingles, provided local building codes allow it. While shingle removal is the preferred route, tear-off is messy and raises the cost of the job. If trapped between the metal roofing and old roofing, moisture can build up and cause mold and rot.28 Dec 2021
What do roofers do with old shingles?
Recycle them. Many roofing contractors offer cleanup services alongside their re-roofing surfaces and will take your old, worn-out shingles to a shingle recycling facility so that the materials in the shingles can be repurposed and reused.19 Jun 2021
Can you put a new roof on top of an old roof?
Roofing over an existing roof is also called reroofing or an overlay. It is the process where roofers install a new roof over your existing one, i.e. add a new layer of shingles, which means that there is no tearing off of the old roof.
Is it a good idea to put a second layer of shingles on a roof?
A second layer of shingles will decrease the integrity of your new roof and lower its lifespan. That's because shingles aren't designed to have a second layer of shingles on top of them! Plus, all that extra moisture and heat being applied to the first layer of shingles will make that first layer age faster.9 Apr 2021
Is it bad to put second layer of shingles?
Adding a second layer of shingles will make your roof hotter because heat gets trapped between the shingle layers. Increased temperatures can lead to premature aging of the shingles. Layering new shingles on top of old ones, which might be curved or damaged, can result in some visible imperfections on your roof.24 Aug 2018
How many layers of roof shingles are allowed?
2 layers
Is it bad to overlay a roof?
By overlaying, you're essentially adding another roof to the top of your home. Another roof adds weight to the top of your home, which can put the structural integrity of your roof into question. Depending on the age of the existing roof, it could be uneven due to years of wear and tear.28 Nov 2021
How much does it cost to overlay a roof?
On average, reroofing a house could cost between $5,000-$12,000, but prices are dependent on many different factors.24 May 2019
How many times can you overlay shingles?
It's always a good idea to review any applicable codes before you launch a repair or renovation project. While local codes can vary, the majority of building codes do permit up to two layers of organic or fiberglass asphalt shingles for roofs with up to an 18.5-degree pitch.29 Nov 2021