If the tiles are installed in an area where weather conditions aren t too severe and damaged tiles and slates are quickly repaired the roof will pretty much take care of itself.
Shallow pitch roof slates.
The tiles and slates used for low pitched roofs are very low maintenance and will always come with a manufacturers guarantee for at least a few decades.
Slate pitch 8 12 20 12 3 headlap.
Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more.
Headlap is typically 3 inches but could be 2 inches on a very steep slopes or 4 inches on very shallow slopes page 247 slate pitch greater than 20 12 2 headlap 20 rise per 12 run 59 04 angle of incline.
It is uncommon to find a roof below 15 but for those very low pitch applications there are interlocking clay pantiles available suitable for use down to 12 5.
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.
Iko roof fast 95 base is a self adhesive product that can easily be cold applied on low slope roofs.
Most roof materials have a recommended pitch range for which they are most appropriate.
For example wood and slate shingles might work for roofs steeper than the top recommendation of 12 12 but you should not install them below the 4 12 lower range.
The rules can occasionally be broken but generally you should not exceed the low range of the recommendation.
In order to provide you with the opportunity to specify low pitched slate roofs below 20 with confidence siga commissioned the bre to carry out a set of tests.