Adding velux windows to old extension

[Jimmy_103]

I'd like to add a couple of roof windows to the pitched roof above our kitchen to let more light in, as well as a window on the external wall but that is more straightforward.

The kitchen is a combination of an old off-shot kitchen (half the width) plus a later (but still old) addition to make it the full width. As a result, the roof is non-symmetrical - see photos, and half the ceiling is flat, half is vaulted.

We would like one velux-style roof window on each face of the roof, and ceiling to be vaulted so it follows the pitch to allow the light into the room (rather than a sun tunnel). The foul pipe from upstairs bathroom runs along the apex of the roof, so the ceiling would have to be below this level.

I've had a look behind the plasterboard ceiling and there's all sorts of roof trusses and rafters that I'm trying to make sense of and will provide pics once I devise a way to take photos without ruining the ceiling.

My question is whether what we want is feasible, or if the complexity of the roof means that it will be a much bigger job than we want? Any advice is most welcome!

 

[jake7462]

Yes completely feasible - if you’ve got trusses then you might be limited to positioning your rooflight between trusses to reduce the extent of structural works required, otherwise it’s just a case of forming a new opening in the roof and doubling up the rafters either side of the new roof light

 

[Jimmy_103]

Thanks, sounds positive. Is it ok to remove all the ceiling joists so that the new ceiling will be vaulted? I always thought they were part of the roof structure? In on of the photos, I've labelled a 'wood beam' which seems to support a lot of the roof structure - guessing this would have to stay in which case I can't see how a vaulted ceiling would be possible? I'll try to get some photos of the roof internals this morning

 

[jake7462]

It depends how your roof is formed - Unless you have a ridge beam that supports the rafters, the ceiling joists will be tying the roof together and stopping it from spreading.

If not then you can install a new ridge beam to support the rafters to allow you to form a vaulted ceiling

 

[Jimmy_103]

Ok thanks. Would installing a new ridge beam make it a big job? We were hoping the 2 velux's plus new ceiling would be under 2k all in

 

[noseall]

Yes completely feasible

What's going to hold the roof up when the customer chops a big chunk out of that timber beam when he forms the Velux light-well?
Not to mention the slender amount of (beam supporting) masonry remaining when that window gets chopped into the gable end. And the waste water will be dizzy by the time it's wound its way through the twisty 40mm waste pipe and curly SVP.
Is the shallow side of that roof steep enough to accommodate the minimum pitch for a Velux?

 

[jake7462]

What's going to hold the roof up when the customer chops a big chunk out of that timber beam when he forms the Velux light-well?

He wants to vault his ceiling across the kitchen - which will obviously involve removing that timber beam, regardless of whether or not he wants to install any rooflights?
Which leaves you looking at needing a ridge beam as I mentioned...

 

[noseall]

He wants to vault his ceiling across the kitchen - which will obviously involve removing that timber beam, regardless of whether or not he wants to install any rooflights?
Which leaves you looking at needing a ridge beam as I mentioned...

Ah gotcha. Feasible as long as you are completely re-building the roof.

 

[jake7462]

Ah gotcha. Feasible as long as you are completely re-building the roof.

I mentioned a ridge beam to allow you to take out the purlin and ceiling joists - Who said anything about completely rebuilding the roof?

 

[noseall]

I mentioned a ridge beam to allow you to take out the purlin and ceiling joists - Who said anything about completely rebuilding the roof?

Have you actually looked at the position of that beam (in relation to his outside elevation image) and what it is doing and how a ridge beam in his roof layout will actually work? Plus the location headache of imposing loads onto a new opening.

Feasible my erse.

 

[Jimmy_103]

So if it can't all be done, is there an easier plan b to get more light into the room? Not end of the world if we end up with 1 velux instead of 2 but I can see how that will work with current ceiling layout.

Pitch of shallow roof is 15 degrees so should be just about okay. With gable window in, there will still be 1m+ of untouched masonry which I assumed would be fine to support changes to roof? As for the waste pipe, I'd assumed 4 45degree bends would be OK as it would still be steep - what problems might I have with this?

I should add that I don't plan to do anything to the roof myself, and will be getting pro's in for opinions

 

[catlad]

Jimmy you need to set your sights a bit lower! I don't think Jake has enough experience to know what's involved. Put a flat roof sun tunnel near the doorway and put the window in the gable end.

 

[noseall]

So if it can't all be done

I'm not saying it can't be done, rather it could be done with plenty of cash and a lot of disruption to the kitchen.

I'd assumed 4 45degree bends would be OK as it would still be steep - what problems might I have with this?

You'd be better off digging the drain to the other side of the window and having the vertical SVP there.

 

[23vc]

If you’re going to do the soil pipe bendy diversion round the window (which wouldn’t look great) fit an access branch/bend on the lower bend

 

[Jimmy_103]

I'm not saying it can't be done, rather it could be done with plenty of cash and a lot of disruption to the kitchen.

You'd be better off digging the drain to the other side of the window and having the vertical SVP there.

OK thanks, I'm trying to get my head around what would be involved in doing everything (2 roof windows plus gable window and changing the roof so it can accommodate a vaulted ceiling) versus doing a bit (gable window plus one roof window). Any idea of approximate costs and time for the whole-hogg approach, and what it would actually involve roof-wise?

For the drain, surely putting in two bends at the top, digging it out and diverting the below-ground rain is more work than just diverting it top and bottom, and also potentially reduces the below ground gradient. I know aesthetically it wouldn't look great, but it doesn't look great now and either way will have bends. Can always disguise the lower bends with a well placed bit of furniture.

If you’re going to do the soil pipe bendy diversion round the window (which wouldn’t look great) fit an access branch/bend on the lower bend

Good idea - would this type of thing do the job if the vertical connection was capped off to act as an access? Can't see any access branch/bends that aren't 90 degrees - https://www.drainagepipe.co.uk/solvent-weld-soil-branch-135-degree-x-110mm-black-p-SS211B/