Traditionally a minimum roof pitch of 20 was recommended in bs 5534 but modern tiles and slates have now been designed for applications as low as 15.
Minimum angle for tiled roof.
This means for every 12 horizontal units the roof must rise a minimum of two and one half vertical units.
The minimum slope or pitch fopr atile roof will depend on the exact profile of tile you are using.
The irc recommends a minimum pitch of 2 5 12 for these materials.
Although the minimum roof pitch for residential homes may vary depending on city and state building codes.
You can also read more about the reasons for choosing low pitch tiles and the requirements in our blog.
Ratios from that minimum up to 4 12 which are considered low pitch require double underlayment.
Minimum roof slope roof pitch r905 3 2.
Concrete is long lasting with a minimum lifespan of 50 years depending on climate.
Clay tiles are colorfast which means their tints improve rather than fade over time.
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.
Low pitches are often found on extensions to properties where the angle of the roof is limited due to obstructions such as second floor windows.
However with modern roofing materials such as boral roofing tiles the minimum roof pitch can be as low as 15.
In traditional home construction it was not recommended to have a roof pitch lower than 20.