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.
Is it bad to have 2 layers of shingles?
Warranty issues: Most shingle warranties do not apply when shingles are layered over existing roofing, according to InterNACHI. Two layers of shingles trap more heat, which in turn damages the shingles and shortens the life span of the roof. … Adding a second layer could compromise the structure of your roof.
Is it a good idea to put a second layer of shingles on a 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.
What is Double Layer shingles?
First of all, multiple layers of shingles simply means layering a new asphalt shingle roof on top of the old one rather than stripping the roof completely to expose the sheathing and replacing it with new shingles.
Is it OK to put new shingles over old?
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.
How many layers should a roof have?
Most building codes allow two layers of organic or fiberglass asphalt shingles on roofs with a 4/12 pitch or less, and three layers on steeper roofs. If the structure can support the added weight, a typical 20-square (2,000-square-foot) reroof will cost at least $1,000 less than a tear-off job.
How much does it cost to put a second layer of shingles on a roof?
A one-story roof with a single shingle layer costs between $100 and $150 per square to remove; a double layer, $115 to $165; and triple layer, $125 to $175. If you have a particularly high roof or one that is extremely steep, you will pay more per square.
How many times can you shingle over a roof?
Depending on the type of roof material used, the number of layers added to a roof range from two to three times. House roofs should never exceed three layers of shingles. Adding additional layers without excavation can save homeowners up to $1,000 in labor.
How long does a reroof last?
The 26 gauge and 29 gauge cheaper metal roofing options can last for up to 25 years if taken care of. On the high-end, the 24 gauge metal roofing option can last for up to 50 years. However, most manufacturers offer a 20-year warranty and some even a lifetime warranty which is dependent on the metal used.
How do I know if my roof has two layers?
One way to tell is that the roof will look a little lumpy overall instead of flat like a normal roof. Another way to tell is to get up on a latter and examine the edge of the roof for multiple layers of shingles. Although the roof-over is more cost effective, it does not last as long as a roof replacement.
How do I know how many layers of shingles I need?
Another thing to observe is the edge of your roof. You can climb a ladder and look at the very edge of your roof’s shingles. If you can see four layers of shingles, that is indicative that your roof was roofed over.
Can a 2 layer roof be repaired?
If you already have two layers shingles, the decision is made for you. The International Residential Code says that you cannot put a new roof over two or more applications of any type of roof covering. Part of the reason has to do with weight and its effect on the structure of your home.
How long does a 2 layer roof last?
Vented properly and installed correctly, you should get around 80-85% of the life span out of an asphalt roof. That means you can expect to get about 20-22 years out of your 3-tab shingle roof and 25-28 years out of your dimensional shingles.
Is two layers of shingles better than one?
While it may seem that two layers of roofing equals twice the protection, this is in no way true. Quantity does not equal quality. Here’s why: A) Foregoing the cost of tearing off the old shingles means that you are also foregoing a chance to inspect the underlying materials.