The minimum slope of a roof depends on the roof s profile.
Minimum slope for slate roof.
The profile is the shape taken by the sheets when you bend them to form panels.
The recommendations shown above are based on a maximum height to eave of 12m and a maximum rafter length of 9m in moderate exposure and 6m in severe exposure.
Asphalt shingles continue to be the most widely installed roof covering option in north america.
Built up roofs require a minimum roof pitch of 1 4 12 or greater.
Wood shingles require a minimum roof pitch of 3 12 or greater.
Minimum pitch for slate roof when considering the minimum pitch for a slated roof it is necessary to establish the exposure of the site the length of rafter and the height of the building.
Conventional low pitch slate roofs are recommended down to a minimum of 20 in areas of sheltered or moderate exposure providing a 500x300mm slate is used and a headlap of 115mm.
As per the nrca roofing and waterproofing manual fifth edition they recommend that roof deck slopes intended for the application of steep slope materials at 4 12 18 degrees or greater page 405.
What does minimum roof pitch mean.
The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
Generally a slate roof is not installed on a pitch less than 4 12.
Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater.
Express the slope of a metal roof by a ratio which indicates the pitch of the roof.
The general recommendation for the minimum pitch for natural slate is 25.
These factors include the pitch of the roof the type of slate being used the size of the lap the size of the slate as well as the site s exposure rating.
There are some manufacturers that can go slightly lower such as the siga 56m natural slate which can go down to 20 in some instances if used with slate hook systems.
They provide excellent weather resistance great value and now more than ever a tremendous range of beautiful designs and color blends.
Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more.
With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
The slope of a roof is often referred to as the roof s pitch.
You need to consider the slope requirements of each panel to determine this minimum slope.
Slate and slate type shingles require a minimum roof pitch of 4 12 or greater.
