Install Rafters Over Low Slope Roof

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Install rafters over low slope roof.

The way pitch also known as roof slope is measured is rise over run. Building installing roof rafters. The cheapest option would be to leave the old roof in place and place the new rafters over the existing roof. If there are gutters installed on the eaves the eave flashing should be installed to overhang the lip of the gutter by about 1 2 inch.

A 2 4 wall with a 2 6 rafter can be notched for a 4 seat. Or join the members using manufactured metal splice plates. Are the rafters built using roof trusses a. You ll need 8 or 9 inches of cellulose to get r 30.

Use premade roof trusses premade roofing trusses will be easier and take less time than installing a stick built roof. First check with your roofer that the type of metal roofing that you intend to install can be used on a low slope roof. A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. There are lots of ways to insulate a low slope roof and most of them are wrong.

Use a framing square to help lay out the notch based on the slope of the roof. Does this diagram look like a good approach a. How to install a roof over an existing roof. Premade trusses will form the skeleton of your new roof above your old roof.

In older buildings the usual method is to install fiberglass batts or cellulose on top of the leaky ceiling with a gap of a few inches or sometimes a few feet between the top of the insulation and the roof sheathing. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging. Installing a new roof over an existing one also called a layover or nailover is often possible although not always the best option. How to build a shed roof step by step.

Roof pitch is the measurement of roof steepness. For our 4 x8 lean to example using a 2 4 rafter the depth of the birdsmouth is limited by the 1 3 depth of the rafter rule. Learn more about common installation practices for low slope residential applications including why owen corning deckseal roofing system is a preferred choice. To do this butt the ends of the rafters together over a supporting beam.

So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12.