by Federico Daugherty
Published 3 years ago
Updated 2 years ago
In most states, you're only allowed to have 2 layers of shingles on a roof for fire safety reasons. However, you'll still see roofs that have 3 or 4 layers today. If you already have 2 or more layers, a contractor will recommend a full replacement.Sep 10, 2021
Can I put 2 layers of shingles on a roof?
As mentioned above, homeowners are legally limited to two layer of roof shingles. Therefore, if you already have two layers, you'll need a full tear-off. Additionally, if your roof is severely damaged, it likely won't be able to support the weight of a reroof and will need to be torn off.
How long will a 2nd layer of shingles last?
around 16 yearsShorter lifespan – As you might expect, new shingles laid over damaged shingles and rotting decking won't last as long as they could. To make matters worse, a roof with two layers of shingles holds in more heat, which speeds up deterioration. On average, an overlay lasts around 16 years.
Is it OK to overlay shingles?
A: In general, it is not good practice to overlay a traditional asphalt shingle roof versus a complete tear off and replacement for the very reason you stated: you can't examine the decking to determine if there is any damage that needs repaired.
What is the problem with more than two layers of shingles?
Having multiple layers of shingles is going to make your roof hotter because the heat gets trapped between the layers, which could mean premature aging of the shingles. This is especially true if you've overlayed your new shingles on top of warped shingles.
Is it OK to reroof over old 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.
Can you shingle over one layer of shingles?
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 the old roof will not be removed/teared off.
Is a roof overlay worth it?
In the long run, an overlay roof is likely to cost more than a complete tear-off and re-roof installation project. That said, an overlay roof will save you money upfront, and can be done more quickly if you're on a time crunch.
How do you blend old shingles on new roof?
The easiest way to tie in the new shingles with the old is with a cut valley (see Four Ways to Shingle a Valley). After the addition roof is framed and sheathed, snap a line on the existing roof shingles 2 in. up from the valley center, and cut through the shingles and underlayment.
Is it better to remove old roof?
The main advantage of leaving the old roof on is obvious—you can minimize the mess, removal costs, and disposal expense if you can leave the old shingles in place. Other advantages are that you end up with an extra barrier against leakage and a little extra insulation.
Can you put 2nd layer on roof?
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.
Is it OK to roof over an existing roof?
Installing a new roof over an existing one can only be done if you have shingles because you can only put shingles over shingles. It is not possible to mix materials, nor to install a new layer over slate or wood tiles.
4 hours ago
Two layers of shingles trap more heat, which in turn damages the shingles and shortens the life span of the roof. Savings: Saving on the initial shingle installation doesn’t solve the long-term cost of adding a second layer of shingles. Roofers will have to work harder and longer to remove two layers of shingles later, making the savings only temporary.
26 hours ago
· Like many common home improvement questions, the answer is you can, but you need to decide if layering shingles is the best course of action for your home. It isn’t uncommon to layer a second roof right over the first and then tear everything off before you put a third layer down. Building codes and most municipalities will usually allow you to overlay a second …
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· Local building codes. Many municipalities have building and fire codes that address shingles and the layers allowed. Generally two are permitted before a tear off is required.
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· In most states, you’re only allowed to have 2 layers of shingles on a roof for fire safety reasons. However, you’ll still see roofs that have 3 or 4 layers today.
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· Is it okay to put the new shingles right over the old ones? If you need to redo your roof, you might be tempted to save some money by having another layer installed over the existing shingles. But ...
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Most building codes allow for two layers of asphalt shingles on a house, so stripping off everything down to the plywood sheathing may not be your only choice. Nailing new shingles over existing ones is less expensive and faster, requiring less labor, but it also means you lose the chance to assess the sheathing for signs of water damage.
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· Yes: although it’s uncommon, you can get shingles multiple times. Shingles is caused by the varicella-zoster virus, which is the same virus that causes chickenpox. The virus sticks around in your body after chickenpox symptoms go away, lying dormant in your nerves, held in check by your immune system. It can re-emerge years or decades later as shingles, a …
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· Install Flashing. At the eave and the rake, install U-shaped drip-edge flashing made for reroofing jobs. Install the eave piece first, then the rake piece over it. The two pieces should meet neatly at the corners. Drive nails at high points on the underlying roof, the bottoms of the shingles. Step 6.
