Low pitch problem

[chrisvrscrx]

Hi

I have a problem. I'm doing a rear kitchen extension the full width of our semi detached house.

I haven't had plans drawn and am taking advantage of the new planning rules to go greater than 3 metres from the back.

I've gone 5 to the outside wall of the new extension.

Due to the windows above we're having trouble getting the 15 degree pitch and have had to upgrade to 9x2 timbers due to the large span.

Does anyone know what purlin I need to go back to 6x2's as ill just achieve the 15• pitch. Currently I'm at 14.6 but I want velux (or equverlant) windows.

Thanks

 

[tony1851]

What width is the extension (ie side-to-side)?

 

[chrisvrscrx]

6.5m outside to outside

 

[tony1851]

A 152 x 152 x 30 UC would do.

 

[chrisvrscrx]

Would a bco accept this?

Does the wood locate into the web of the steel?

I was also thinking maybe of getting an oak beam and leaving it exposed. Does anyone know what spec this would have to be?

Thanks

 

[chrisvrscrx]

I've seen this

http://bit.ly/1feTg61

 

[tony1851]

Would a bco accept this?

Does the wood locate into the web of the steel?

I was also thinking maybe of getting an oak beam and leaving it exposed. Does anyone know what spec this would have to be?

Thanks

It's at the inspector's discretion as to whether he accepts it or requires calcs.
You would run the rafters on top of the steel, with a 4x2 timber bolted to the top.
If you use a green oak beam,it will warp, twist and develop shakes after a year or two. It won't be a problem structurally but your roof might be up and down a bit.

 

[Dave350z]

Don't FAKRO do windows that are 10 - 15 Degrees pitch? Or some kid of Kit they supply... Could be wrong.

 

[catlad]

Yes they doing a new flat roof skylight 2-15 degrees not sure if its out yet.