Roof Layers How Many

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

Roof layers how many.

Here are the layers of a roof in order of application bottom to top. You can usually see the underside of plywood decking from the attic. 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. When it s time to replace your roof there are several factors that might lead your roofing professional to.

On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing. As a result you may consider questioning exactly how many layers of roof can be added to an already existing flat roof. Most roof decking is made from sheets of plywood. While putting a roof on a home or building seems like a relatively standard job there are many regulations that must be followed to ensure the job is done right.

Steep sloped roof products such as tile slate metal and shakes only allow one layer. Depending on the product of roofing that the flat roof currently contains the roof can have a specific number of layers. After the roof is stocked the laborers pry up several layers of cap shingles at a time and toss them into plastic trash bins see figure 1. Roof products with steep slopes such as metal slate tile and shakes may only be able to have one.

How many layers of shingles are allowed on a roof. It provides structure by tying the trusses and joists together. Most building codes allow up to two layers of organic or fiberglass asphalt shingles. Decking most often made out of plywood this roof layer is installed over the framing in a typical roof install.

Benefits of adding multiple shingle layers. California roofing codes establish a list of rules that all builders and contractors must adhere to in order to ensure safe building practices within the state. That limit pertains to roofs with up to a 4 12 pitch. If the underlayment is old and deteriorated it won t protect your roof deck from water that gets past the shingles.

The roofing crew uses a red ripper roofing demolition tool to pry up cap shingles which are collected in a plastic bin along with old boot flanges and any loose shingle tabs. For many years it was acceptable to put even the third layer. Now you just have to decide whether to remove the existing roof shingles or recover the roof. The building paper tarpaper that s laid between the roof sheathing and the shingles is there for a very good reason because water has a way of getting under shingles no matter how many layers of roofing you have.

Water shield is the next roofing layer that creates a water proof barrier where ice or water can buildup near the roof eaves. Once you have discovered how many layers of roof shingles are allowed the next decision you should make is whether you will have the existing shingles completely removed to make way for two or three new layers or whether you will have another layer of shingles placed on top of the existing layer. Re roof or strip the roof down.