Install Rafters Over Low Slope Roof

You ll need 8 or 9 inches of cellulose to get r 30.

Install rafters over low slope 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. Or join the members using manufactured metal splice plates. 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. 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.

Roof pitch is the measurement of roof steepness. 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. A 2 4 wall with a 2 6 rafter can be notched for a 4 seat. The way pitch also known as roof slope is measured is rise over run.

Place corner pieces where panels will meet bends at the edge of the roofing. Premade trusses will form the skeleton of your new roof above your old roof. How to build a shed roof step by step. How to install a roof over an existing roof.

Are the rafters built using roof trusses a. Building installing roof rafters. There are lots of ways to insulate a low slope roof and most of them are wrong. Does this diagram look like a good approach a.

Then nail two pieces of 1 by or 2 by lumber of the same width as the rafters as show at left and about 18 inches long centered over both sides of the splice. A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. Learn more about common installation practices for low slope residential applications including why owen corning deckseal roofing system is a preferred choice. Use 1 1 4 inch nails to cover the outline of the roof with strips of metal eave flashing also called edging.

Use a framing square to help lay out the notch based on the slope of the roof. Use premade roof trusses premade roofing trusses will be easier and take less time than installing a stick built roof. The cheapest option would be to leave the old roof in place and place the new rafters over the existing roof. 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.

Some types of metal roofing can t be installed on a 1 12 roof.