Combination roof.

[bhaforever]

Hi,I am doing a small single story extension on my house and it requires a combination roof which is hipped at the bottom and flat on top.
Has anyone got any details on how this should be pitched as i cant find it anywhere online.

Many thanks in advance.

 

[noseall]

it's reasonable straight forward for a roofer, just more awkward to pitch up.

you end up with a square or four sided ridge as opposed to a single element.

the ridge does require additional support or propping as the rafters to not entirely take the weight. propping will depend upon joist alignment but is usually done with 100x100mm timber props or by carrying a structural wall up to the ridge sections. the props can either sit on double joists, spread across joists laterally or sit on steels.

hip roofs are certainly the more difficult, especially with a flat top.