Roof pitch too shallow for velux

[Phillip Stephens]

Hello All, we are undertaking a rear extension and are in a bit of a situation regarding the roof. The builder has put in the header and rafters but there is a 12 degree pitch (2.5 in 12 inches) so we're struggling to get the pitch to fit a velux which I think requires a 15 degree pitch.
No battens or roof tiles have been installed yet. The builder is reluctant to re-install the header/beams and has suggested we could use timber firrings on top of the roof beams to give us the 15 degree pitch we need. Would this be an acceptable solution? I think the firrings will need to be in the region of 180mm or so to give us the pitch. The roof run for the extension is 3100mm. Thanks

 

[^woody^]

Velux make a specific upstand adapter for these occasions.

 

[Phillip Stephens]

Thanks Woody. The cost for these upstands (almost as much as the velux itself) are quite prohibitive. Also we are trying to retain a flush finish if possible. Would the firrings proposal work as this would increase the pitch for the whole roof?

 

[^woody^]

Why did your poxy plan drawer design a roof and rooflights that don't work together?

If your builder was a bit clued up, he could make the upstand, but otherwise yes furrings can work if properly fitted - they may well need a ply or steel gusset.

 

[Phillip Stephens]

you're right Woody. The architect has been a real let down. We're struggling through the build with a lot of to'ing and fro'ing with BC. Thanks for the advice.

 

[catlad]

I confused how can timber firings work were rafters can't?

 

[Phillip Stephens]

The rafters are unfortunately already installed and is currently providing a roof pitch of 12 degrees. The firings will be retro-fitted to these rafters and tied in as Woody has suggested with gussets. The fall on the firings will be aligned to provide the 15 degree pitch for a Velux.

 

[freddiemercurystwin]

If the builder was clued up he would have built it at the right pitch in the first place.

 

[Phillip Stephens]

I don’t disagree Freddie. It’s been a struggle to get this far - weeks if no work, loads of stuff having to be re-worked. Unfortunately I have too much invested to cut my losses.

 

[noseall]

The rafters are unfortunately already installed and is currently providing a roof pitch of 12 degrees.

That should have set off alarm bells (12 degree pitch) immediately.

 

[catlad]

You have to ask yourself do you want to move forward with someone who dose not understand the basics.

 

[freddiemercurystwin]

You have to ask yourself do you want to move forward with someone who dose not understand the basics.

It's OK, there's a roofing section on the forum for when the inevitable happens ....