Proper Roofing Underlayment Installation

There is a direct connection between membrane performance and proper application.

Proper roofing underlayment installation.

Roof slopes greater than 4 12 require only one layer of underlayment. This article series discusses roofing felt specifically addressing the roofing code or roofing manufacturer s requirements for use of an underlayment such as roofing felt tarpaper or other underlayment products beneath asphalt shingles and other. Gcp applied technologies grace ice water shield roofing underlayment requires side laps to be a minimum of 90 mm 3 5 in and end laps a minimum of 150 mm 6 in. Synthetic roofing underlayment is to be laid horizontally parallel to eave with printed anti slip side up starting at the bottom of the lowest roof eave with a 1 5 underlayment overhang at the eave covering the pre installed eave drip edge.

It starts with installing solid decking usually plywood or oriented strand board but that is not waterproof. For three tab shingles place two quarter size spots of plastic roof cement under the lower corners of each tab as shown in figure 2 7. Center a minimum 610 mm 24 wide minimum 28 gauge pre finished galvanized metal valley liner in the valley and fasten with only enough nails to hold it in place nailing at the edges only. Ideally the roof covering material would be installed as soon as possible but in reality the roof may be protected by only the underlayment for days weeks or sometimes months.

Roofing underlayment roofing felt requirements. It must be covered with waterproofing membrane usually roof felt also. Is roofing felt required. Minimum overlap guidelines are set by the manufacturer.

Overlap each metal piece by at least 150 mm 6 and use asphalt plastic cement under each section of overlap. Felt details for various roof slopes amp.