DIY Doctor UK DIY Forums

Hi there,

I'm making double hipped lean-to roof over a square bay window.

The bay is 2700 wide with a 650 projection.

So the roof run will be about 650mm, the rise, I imagine will be about 540mm, roughly around 40 degree pitch. I can go steeper if needed but the neighbour has a similar bay with a similar pitch so will be good to look similar to theirs.

I plan to use smooth interlocking tiles, with mini hip tiles on the hips (you know, the smaller version of regular hip tiles).

With it being a small roof with little weight, I'm just trying to work out what would be the best timbers to use for the framing of the roof. I have built a couple of roof's similar but am no expert roofer, still very inexperienced, so I don't know the regular rub of things.

I would probably plump for 5 or 6 x 2's normally, but on this, I would be tempted to go for 4 or 5 x 2's. Can anyone advise whether that would be acceptable on a roof this size, or do I need to stick to the bigger 5 or 6 x 2's?

Thanks again for any advice or opinion.

take a look at www.easeyrafters.com should give somw idea. May even look like your bay roof.

A guess 4" x 2" , so take in to the size weight they will carry when setting spacing. I did a pent porch roof in 4x 2 @ 16" centres. still up no sag after 28yrs. Don't forget the felt under battens and insulation on the ceiling