Changing kitchen ceiling for skylight installation

Section62

Bendy_House said:

Of course.

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

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

(1) I was responding to the part of your post I highlighted in bold, not the BC part.

It probably isn't a straightforward job, and possibly does need a new roof.  My reference to BC was that they will want assurance about the structural alterations being safe... therefore the fact BC should be involved means that the roof alterations can't be done on the basis of guesswork.

(2) The OP said "I want to remove the ceiling and construct a new sloped ceiling with a velux."  t-p has pointed out the need for larger rafters for a vaulted roof. I've pointed out the potential for structural issues.

Also, if you look closely at the rafter on the right-hand side of the OP's first picture it appears it may not be in (full) contact with the wall plate.  Whether or not the ceiling josts act as ties is uncertain.

The OP said "I assume it is more complicated than just removing the plasterboard and beams".  On that basis I'd be surprised if you are correct that the OP would find it "concerning" that the best/cheapest/quickest option could be full replacement of the roof, but if they are, then perhaps they should reconsider whether a project like this is for them.

Sometimes trying to find a short-cut to doing a job can result in a really poor result.  This is one of those cases - not accepting replacement of the whole roof as a possible option to achieve a vaulted roof would potentially rule out achieving the best overall outcome.

It needs an architect/SE to have a good look at the existing structure and space and advise on the best way to go forward.

stuart45

It's probably better if the OP is prepared for a new roof. The covering might be able to be re-used, but will benefit from a new breather membrane, as the old one looks like felt.

GDB2222

Section62 said:

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.

I did not buy a house because there were insufficient ties in the extension roof, and the walls were leaning outwards. 

GDB2222

Surely, in this case, the easiest would be long narrow velux windows, sized to fit between the existing rafters? Do every other one, with insulation and boxing in between. That retains the flat ceiling and all the existing timbers. 

Section62

GDB2222 said:

Surely, in this case, the easiest would be long narrow velux windows, sized to fit between the existing rafters? Do every other one, with insulation and boxing in between. That retains the flat ceiling and all the existing timbers. 

Possibly, but it might look really odd, and the extra cost of buying/fitting a larger number of small windows vs a smaller number of larger ones could be greater than the cost of converting to a vaulted ceiling.

One of the other factors to consider is the type of roof covering, and if (say tiles) where the laps are relative to the proposed window locations.  A roofer could spend inordinate time cutting tiles and fitting the flashings around the window(s) located to fit the existing roof, vs positioning the window(s) so they fit to the tiles.  The more windows, the more fiddly work the roofer will need to do.  In comparison, stripping the roof and starting again could be quicker. (but depends on the size of the roof and the window(s))

Gavin83

The ceiling joists look too big to just be acting as support for the plasterboard, plus as mentioned it doesn’t appear there is much contact between the rafters and the wall.

Could you poke your head in that hole and check if there’s a join (a bolt or such like) between the joists and rafters? Also check how the wood connects to the wall.

I suspect the joists are structurally important and therefore agree with the others you’ll likely be requiring a new roof.

Section62

Gavin83 said:

Could you poke your head in that hole and check if there’s a join (a bolt or such like) between the joists and rafters? Also check how the wood connects to the wall.

You have to be careful with this though, there's a difference between what is actually there and what should be there.

For example, there's no visible sign of fixings from the side of the (wall end) hanger into the ceiling joist.  If the joists aren't fixed at that end then they can't be acting as ties.

But is the absence of fixings because they weren't needed, or because the builder forgot to do it?

Gavin83

Section62 said:

Gavin83 said:

Could you poke your head in that hole and check if there’s a join (a bolt or such like) between the joists and rafters? Also check how the wood connects to the wall.

You have to be careful with this though, there's a difference between what is actually there and what should be there.

For example, there's no visible sign of fixings from the side of the (wall end) hanger into the ceiling joist.  If the joists aren't fixed at that end then they can't be acting as ties.

But is the absence of fixings because they weren't needed, or because the builder forgot to do it?

I agree, any fixing should go through both sides and it clearly isn’t there on the side we can see. There doesn’t appear to be any fixings of note anywhere though but they have to be connected somewhere.

The OP needs a professional on this but it wouldn’t hurt to have a rough idea of how it all fits together.

Bendy_House

Section62 said:

Bendy_House said:

Of course.

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

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

(1) I was responding to the part of your post I highlighted in bold, not the BC part.

It probably isn't a straightforward job, and possibly does need a new roof.  My reference to BC was that they will want assurance about the structural alterations being safe... therefore the fact BC should be involved means that the roof alterations can't be done on the basis of guesswork.

(2) The OP said "I want to remove the ceiling and construct a new sloped ceiling with a velux."  t-p has pointed out the need for larger rafters for a vaulted roof. I've pointed out the potential for structural issues.

Also, if you look closely at the rafter on the right-hand side of the OP's first picture it appears it may not be in (full) contact with the wall plate.  Whether or not the ceiling josts act as ties is uncertain.

The OP said "I assume it is more complicated than just removing the plasterboard and beams".  On that basis I'd be surprised if you are correct that the OP would find it "concerning" that the best/cheapest/quickest option could be full replacement of the roof, but if they are, then perhaps they should reconsider whether a project like this is for them.

Sometimes trying to find a short-cut to doing a job can result in a really poor result.  This is one of those cases - not accepting replacement of the whole roof as a possible option to achieve a vaulted roof would potentially rule out achieving the best overall outcome.

It needs an architect/SE to have a good look at the existing structure and space and advise on the best way to go forward.

Again, of course.

And I have never at any blahblahblah...