Low Slope Roof Underlayment For Standing Seam Roof

Low slope roofs are not totally flat their roof slope generally ranges from 1 4 12 to 3 12.

Low slope roof underlayment for standing seam roof.

Guide to roofing underlayment installation on low slope roofs with asphalt shingles asphalt shingles can be used on roofs with a slope of 2 12 to 4 12 if double coverage underlayment is used. But the taller profiles like standing seam and pbr shown below can be installed on roofs with as low as 1 4 or 1 2 in 12 pitch. Metal panel roof system description there is only one category of metal roof systems used in low slope applications structural metal panel. 4 12 to 20 12 pitches.

Structural metal panel roof systems can be used for low slope roofs because of their hydrostatic or water barrier characteristics. There are some opinions that standing seam metal roof minimum slope is 12 but it increases the possibility of leaking on the few first days of snow arrival. In country with heavy snow and tough winter days the metal roof minimum slope is recommended to be 1 12. Slopes above 19 12 are not recommended since tiles on very steep roofs can rattle.

Start with a 19 inch strip of 15 lb. On low slope roofs like you have a water proof membrane like i ws is good insurance. Low slope metal roofs have simple geometries and are easier and less expensive to install that medium to steep slope roofs. These advantages and disadvantages do not apply to granulated synthetic underlayment as it is not to be used directly under metal roofing.

If the roof slope is below 3 12 pitch see our previous post on how to determine a roof s pitch the entire roof should be covered but only if the roof is conventionally vented cold roof construction. Low slope metal roofs require less material which reduces the overall load on the building s structure. Their fasteners are either concealed or screwed at the top of a ridge which makes them less likely to leak. Peel and stick is only needed for low slope or if your roof has a issues with ice dams 4a doesn t sound like a climate for that.

Asphalt saturated felt along the eaves and lap succeeding courses by 19 inches as shown in figure 2 3. I don t see any point in sealing the roof penetrations to the sheathing. Lower slopes for low slope standing seam metal roof applications strictly peel and stick underlayment is a better choice. Water that gets below both the roofing and underlayment will cause the same amount of problems whether it permeates the plywood or follows the pipe down.

For pitches of 2 5 12 up to 4 12 the roof requires double underlayment.