Minimum Slope Of Slate Roof

Asphalt shingles continue to be the most widely installed roof covering option in north america.

Minimum slope of slate roof.

Anything above a 8 12 is preferred and slopes in the 12 12 to 18 12 range are probably ideal. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. 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.

The slope of a roof is often referred to as the roof s pitch. 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. Generally the steeper the roof the better with regard to service life of slate. Sig roofing can supply a number of solutions to cope with these lower pitches such as cambrian roof slate or regent tiles which can be used on pitches as low as.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. It takes the manufacturer s recommendations the unique conditions of the roof as well as the skills and the expertise of the installer to arrive at the right slope. In general the minimum slope for a flat roof is 1 0 but as stated earlier this is only possible in theory. But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 12 5 depending on the design of the roof.

The minimum slope of a roof depends on the roof s profile. You consider some alternative solutions. Not only will slate shingles last longer on these steeper slopes but they will be more visible from grade and show off their natural beauty. The profile is the shape taken by the sheets when you bend them to form panels.

This means for every 12 horizontal units the roof must rise a minimum of 4 vertical units. Slate shingles minimum roof slope roof pitch r905 6 2. Wood shingles minimum roof slope roof pitch r905 7 2. Slate shingles can only be installed on roof slopes of 4 12 or greater 33 slope.

Generally a slate roof is not installed on a pitch less than 4 12. It is agreed that the roof pitch should be a minimum of 20 degrees preferably a bit more. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. 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.