How Many Plys To Use On Built Up Roof

The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.

How many plys to use on built up roof.

The average built up roof will have between three and five plies not including the waterproofing membrane layers. A built up roof for example will typically include the built up membrane itself with or without gravel as well as some kind of insulation and cover board which will vary in thickness from roof to roof. Carson dunlop s sketch illustrates a 4 ply built up roof installation. Permaply 28 is designed for use as the first or base sheet in built up roofing or modified bitumen roof assemblies.

Paint exposed flashing cement with uv resistant coating. Built up roofing lifespan depending on the climate and the specific materials used built up roofing has an average life expectancy of 15 to 30 years but some constructions can last up to 40 years. This price range can change depending on the materials you choose. Sometimes a base sheet used as the bottommost ply is mechanically fastened.

Built up roofing for an average commercial roof it will usually cost between per 5 50 8 50 square foot in materials and labor to install a typical built up roofing system. Labor tasks clear roof surface of debris. Built up roofs generally are considered to be fully adhered if applied directly to roof decks or insulation. Makes it suitable as an intermediate or ply felt in cold applied built up and modified bitumen roof assemblies.

When it comes to estimating the weight of an existing roof field verification of the in place construction is necessary. Exceptionally pliable easy to handle and lays flat. Click to enlarge any image built up roofing is usually used on flat or low slope roofs less than 3 rise in 12 of run. In general built up roofing tends to fare better in warmer climates than in cold regions.

Glue secure and prime flashing. The term four plies denotes a four ply roof membrane construction. Versatile gafglas ply 4 sheet for built up roofing bur offers maximum strength and stability and can be used in all climate zones as a base sheet ply felt and more. Finally the entire surface is coated with a protective top coat such as gravel or clear glaze.

For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended. Built up roof cost estimates may require an onsite inspection. We have found an occasional bur on steeper slopes including a tar and gravel steep slope roof whose gravel kept washing down into the building s gutter. Next the installers will alternate layers of roof felt or fiberglass with mopped on asphalt or coal tar.