2 Layers Roof Shingles

If you are putting a layer of asphalt shingles over an existing layer of asphalt shingles on to a 3 4 inch deck or a plank deck then you should be using 1 1 2 inch nails.

2 layers roof shingles.

Roofers will have to work harder and longer to remove two layers of shingles later making the savings only temporary. 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. Saving on the initial shingle installation doesn t solve the long term cost of adding a second layer of shingles. Two layers of shingles trap more heat which in turn damages the shingles and shortens the life span of the roof.

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. Two layers is the maximum in most areas but some building codes allow only one. Hope you like it. 3 tabs are less expensive but also less durable have lower wind resistance and have a flatter appearance.

The second layer of shingles will trap heat which can result in the decomposition of both roof layers. Asphalt shingles come in two major types 3 tab and architectural. Asphalt shingles typically can have one more layer added over the top two roofs total. If your decking is less than 3 4 inch then a 1 1 2 inch nail will suffice.

In fact the extra layer can reduce your roof s lifespan by up to 40. For many years it was acceptable to put even the third layer. This will force you to replace your roof earlier than expected. Another issue is that when you add in the second layer it can add extra weight to your roof.

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. Steep sloped roof products such as tile slate metal and shakes only allow one layer. Here is a video on how we lay a second layer of asphalt shingles over existing asphalt shingles. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.

But contractors who spoke with angie s list say best practices call for stripping the roof down to the wood deck to inspect it before installing a new roof. Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio.