Originally Posted By: jnosworthy This post was automatically imported from our archived forum.
RR,
I’m not sure there is a reason why you couldn’t use roll roofing on a slope. I know here locally a portion of the civic center roof is barrel shaped. So at some point on the curve the roof is almost vertical near the edges and nearly horizontal at the top of the curve. The thing is that for some reason I can’t remember, the NRCA manuel says that due to the slope in this case, the sucessive courses of mineral roll be laid perpendicular to the horizon. That’s up one side and down over the top, with end-laps etc.
Originally Posted By: rray This post was automatically imported from our archived forum.
I just had one of my home inspectors go down the street to four roofing contractors. All of them said no to roll roofing on slopes, but none of them could offer any reasons why. I’d love to know the reasons.
Originally Posted By: lewens This post was automatically imported from our archived forum.
Russel
Up here in the great white north the standard is anything less than 4/12 is considered low slope and requires rool roofing. They used to manufacture “low slope shingles” for these applications but I think the manufacturers have done away with these. I believe the rational for not using roll roofing on steeper slopes is the mess you would make in trying to keep the tar on a steep slope while laying the roof and I’m sure roll roofing would be to cost prohibitive. On the dome they most likely used a rubber membrane system that is multi layered and layed with heat.
Originally Posted By: mbailey This post was automatically imported from our archived forum.
Russel,
If you are referring to mineral surface roll roofing - other than the aesthetic reasons , short lifespan (approx 10 years in my area) , and typically no warranty other than for manufacturing defects - it can be used on steeper slopes.
Atlas is a manufacturer than comes to mind right away that says mineral surface roll roofing can be used on steeper slopes.
-- Mark Bailey
Stonegate Property Inspections LLC
Ponca, NE
Originally Posted By: jlybolt This post was automatically imported from our archived forum.
Guidelines for rolled roofing that I use is as follows:
General min. allowable pitch depends on the way the rolled roofing is installed.
Rolled roofing applied vertically using the exposed nail method can be installed on roofs as low as 4 to 12.
Applied vertically using the concealed nail method can only be installed on roofs with a pitch as low as 3 to 12
Applied horizontally, exposed nail method can be used with roof pitch as low as 2 to 12
Applied horizontally, concealed nail method, as low as 1 to 12.
Originally Posted By: whandley This post was automatically imported from our archived forum.
You can install shingles and or tiles on pitches below 4/12, but you have to increase and or improve the underlayment installation to accommodate same. Conversely, I find rolled cap sheet roofing surfaces installed horizontally on pitches above 4/12 all the time. This would include both exposed nail and or torch down seam installations.
Originally Posted By: jpope This post was automatically imported from our archived forum.
mbailey wrote:
If you are referring to mineral surface roll roofing - other than the aesthetic reasons , short lifespan (approx 10 years in my area) , and typically no warranty other than for manufacturing defects - it can be used on steeper slopes.
Mark is correct. Rolled comp can be used on sloped roof systems.
-- Jeff Pope
JPI Home Inspection Service
"At JPI, we'll help you look better"
(661) 212-0738
