How Many Layers Of Roof Shingles Are Allowed In Ohio

Most building codes allow up to two layers of organic or fiberglass asphalt shingles.

How many layers of roof shingles are allowed in ohio. The soundness of the building you re re roofing is another consideration. 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. For example cedar or tile roofs are only allowed one layer. Asphalt shingles typically can have one more layer added over the top two roofs total.

For closed valleys valleys covered with shingles valley lining of one ply of smooth roll roofing complying with astm d 6380 and at least 36 inches 914 mm wide or types as described in item 1 or 2 above shall be permitted. 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. In snowy climates most new roofs these days get an ice and water shield a rubbery moisture membrane applied to the sheathing along the eave to protect against ice dams. The 2006 residential code of ohio rco states in section r905 2 7 1 states that when table r301 2 1 criteria so designates an ice barrier that consists of at least two layers of underlayment cemented together or of a self adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the eave s edge to a point at least 24 inches from the inside of the exterior wall line of the building.

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. 3 tabs are less expensive but also less durable have lower wind resistance and have a flatter appearance. Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio. The bottom layer shall be 18 inches 457 mm and the top layer a minimum of 36 inches 914 mm wide.

Steep sloped roof products such as tile slate metal and shakes only allow one layer. Section 1511 3 requires that roof replacement shall include the removal of all existing layers of roof coverings down to the roof deck but it does lay out a series of exceptions. That limit pertains to roofs with up to a 4 12 pitch. Adding a second or third layer of shingles adds significant weight to the structure.

Adding this membrane isn t an option with a re roof and the extra layer of shingles offers little protection against ice dams. Asphalt shingles come in two major types 3 tab and architectural. However this depends upon the roof materials. Finally consider whether reroofing over the old shingles is even allowed where you live.

In the portland area as of 2018 the current code allows up to three layers if the current layer is in good condition. On most flat roofs such as epdm tpo or modified it is perfectly acceptable to two layers of roofing.