How Many Layers Roof Has Shingles

Asphalt shingles typically can have one more layer added over the top two roofs total.

How many layers roof has shingles. Your three layer roof is definitely a potential structural concern and homeowners insurance companies might consider three layers of roof shingles. Roofing layers from the framing to the shingles. Architectural shingles make up most roof replacements today as their cost is only marginally more than 3 tab and they come with far superior specifications and. Good quality composite shingles can weigh 350 to 450 pounds per square 100 square feet of roofing installed.

Chances are your roof structure was designed for a dead load of one layer of shingles plus extra for snow and a safety margin. That limit pertains to roofs with up to a 4 12 pitch. The average 30 square roof uses 90 bundles of shingles and a bundle of asphalt roofing shingles weighs about 100 pounds which means you re putting roughly 9 000 additional pounds of weight on your roof. Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio.

Most building codes allow up to two layers of organic or fiberglass asphalt shingles. A roofing contractor will know exactly how many layers of roof shingles are allowed in your area for your building but it is normal that you will be permitted up to three layers of shingles. 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. For example cedar or tile roofs are only allowed one layer.

For many years it was acceptable to put even the third layer. In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition. For example there s a starter course of roofing shingles installed at the eaves before the roofing shingles you can see. There are multiple layers of materials and they have to be installed in the right sequence and the right way in order to withstand harsh weather and keep your home dry.

However this depends upon the roof materials. Asphalt shingles come in two major types 3 tab and architectural. According to the international existing building code homes can be re roofed one time by applying a second layer of roof shingles over the existing one but after that application begins to wear both layers need to be removed before a brand new roof is installed.