Changing kitchen ceiling for skylight installation

olbas_oil

I want to have a skylight in a kitchen extension. The roof is pitched (about 14 deg) but the ceiling is flat plasterboard. I want to remove the ceiling and construct a new sloped ceiling with a velux.
I seem to be caught between velux installers, who need a sloped ceiling, and roofers who don't install windows. Who would undertake this work?
I assume it is more complicated than just removing the plasterboard and beams. They are on hangers at the original house wall side, but are bolted where they meet the rafters on top of the extension wall. What other fixing will be required for the rafters if the beams are removed? Do I need a structural engineer/ building control, or is this within a builder's remit?

EssexExile

I'm no expert but it looks like you're going to need a new roof. So a structural engineer to design it, a builder to build it, building control to inspect it.

Liverpool85

Yes I think it’ll be a whole new roof type- big job.

otherwise could you get some Veluxes installed with framing? We got these done by our builders, they fit between existing rafters they are insulated around in space between the ceiling and room. The ceiling is then flat but the main roof very pitched 

Bendy_House

What purpose do the horizontal ceiling joists perform? Surely just to hold up the ceiling plasterboards? I mean, they aren't ties, or lend any other type of structural integrity, do they?

The answer is... I don't know. But that's what it LOOKS like, and a joiner/roofer should be able to confirm that in a few minutes, given that you've exposed the area.

So, best case scenario is that these ceiling joists can simply be removed, and the upper, sloping rafters converted into a proper insulated roof, with the skylights installed in it.

Unless I'm missing something, this looks eminently doable. 

A Building Cert-sized job?

FreeBear

Bendy_House said: A Building Cert-sized job?

You have removed more than 25% of the ceiling. Building Control should be notified and they would want to see adequate insulation incorporated.

Adding a velux window would also be notifiable, but that could be done via a FENSA (or similar) installer.

stuart45

Depending on the size of the.window, the rafters may have to be cut, so the regs will apply to this as well as the window itself.

travis-powers

The easiest way would be to form a tunnel as per Liverpool 85 but would need framing out and double rafters either side.
A vaulted roof would need bigger rafters allowing for insulation and air gap.

Bendy_House

Of course, FB, Stuart and Travis. All done under BC. That's what I mean by a 'cert', or what's it called? The same as we had when sis had a structural wall taken down. The BCO looked at the SE's calcs, and came out to check the required beam was put in.

But this is a straight-forward job, surely? Is there any need to even remove the outer roof covering? It surely doesn't need a 'new' roof? Depending on form of design, vents could be added externally along the top.

I suppose stripping the outer covering would be easier, tho'.

Section62

Bendy_House said:

Of course, FB, Stuart and Travis. All done under BC. That's what I mean by a 'cert', or what's it called? The same as we had when sis had a structural wall taken down. The BCO looked at the SE's calcs, and came out to check the required beam was put in.

But this is a straight-forward job, surely? Is there any need to even remove the outer roof covering? It surely doesn't need a 'new' roof? Depending on form of design, vents could be added externally along the top.

As you said....

Bendy_House said:

The answer is... I don't know.

I'd expect the possibility the ceiling joists could be acting as ties to stop the wall moving out and/or the rafters sagging.

Removal of any part of a roof structure should be done under the advice of a professional who knows what they are doing.

Building Control should be involved in a job like this - they will want assurance the structural alterations are safe.

Bendy_House

Of course.

I have never, at any point, suggested that BC should not be supervising this. In fact I made it clear they should be.

All I was pointing out is that this job doesn't necessarily require a 'new roof'; the suggestion that it did I suspect the OP found a bit concerning.

travis-powers

If op goes for the tunnel the original roof can be adapted but bc would want to see double rafters.
A vaulted roof would need new stress graded timbers and ventilation, problematic on a mono pitch roof.