Most building codes allow up to two layers of organic or fiberglass asphalt shingles. That limit pertains to roofs with up to a 4:12 pitch. When it’s time to replace your roof, there are several factors that might lead your roofing professional to recommend adding shingles on top of your existing layers.
What is the problem with more than two 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.
How many layers of shingles can go on a roof?
House roofs should never exceed three layers of shingles. Adding additional layers without excavation can save homeowners up to $1,000 in labor. Therefore, layering has advantages. Building and city codes require roofers to limit shingle layers to two.
Can you put 4 layers of shingles on a roof?
Not completely a huge deal other than tearing off two layers of shingles will raise a new roof price, but having four or maybe even more layers is just plain crazy. … Most residential roofs cannot handle too much weight so having more than two at most, can start to damage the structure of the roof and the home.
Is it OK to put a second layer of shingles on a roof?
“Can I put a second layer of shingles on my roof?” You can, but you probably shouldn’t! Known as a layover, putting a second layer of shingles on your roof is in most cases inadvisable and a job that Proven Roofing is likely to even turn down.
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.
Why is racking shingles bad?
If the racking method has been used, shingle joints align every other course, which increases the chance for roof leakage. … During cold-weather installation, lifting shingle tabs to install the missing nails may crack or crease them. Racking can sometimes result in improper color blending.
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.
Should I remove old shingles when shingling?
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.
Should I overlay shingles?
A builder suggested overlaying over the existing layer of 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.
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 much does a second layer of shingles cost?
ft. The cost per square depends on the type of shingles and the brand. They generally range between $55 on the low end and $600 on the high end, with an average of $100 to $250 per square of architectural shingles. The roofing labor cost per square is $100 to $250.
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.