Left with a big 1st floor wall cavity on patio doors )o:

[bager77]

Hello everyone,
I was really hoping someone might be able to advise me on what I need to do to fix an issue I've been left with.
We have two inward-opening 1st floor patio windows, but the builders have left us with a gap in the floor cavity with a bit of DPM flapping about.
The builder insisted that he hadn't quoted for this work and wouldn't do it (after a major disaster on his part that took months to correct - I think he just wanted to leave).
No cavity closers have been put in place before the doors were fitted - I'm now unsure if I can somehow slide and C1 them in place - but they need to be structurally sound and I don't want to bodge the job. I'm unsure about just filing with cement as I've heard that's not a good thermal way to go - again, I'm afraid of bodging it.
Pics attached showing the two doors as they have been left, there's a cavity under the DPM that goes down one block to the supporting steel.
I really don't know the best way to move forward, but really need to.

Info & vids that I find only talk about putting the cavity closer on pre-window, not once the frame has already been put in (and it's difficult to secure the closer + packers in the way below the frame).

Any thoughts or advice would be gratefully received.
Many thanks,
B

 

[StephenOak]

You are more likely to get help if you post in the appropriate section. The Moderators can move this for you. Click on 'Report' to ask for that.

 

[noseall]

Hello everyone,
I was really hoping someone might be able to advise me on what I need to do to fix an issue I've been left with.
We have two inward-opening 1st floor patio windows, but the builders have left us with a gap in the floor cavity with a bit of DPM flapping about.
The builder insisted that he hadn't quoted for this work and wouldn't do it (after a major disaster on his part that took months to correct - I think he just wanted to leave).
No cavity closers have been put in place before the doors were fitted - I'm now unsure if I can somehow slide and C1 them in place - but they need to be structurally sound and I don't want to bodge the job. I'm unsure about just filing with cement as I've heard that's not a good thermal way to go - again, I'm afraid of bodging it.
Pics attached showing the two doors as they have been left, there's a cavity under the DPM that goes down one block to the supporting steel.
I really don't know the best way to move forward, but really need to.

Info & vids that I find only talk about putting the cavity closer on pre-window, not once the frame has already been put in (and it's difficult to secure the closer + packers in the way below the frame).

Any thoughts or advice would be gratefully received.
Many thanks,
B

Extend the existing joists into the void.

 

[bager77]

Hi Noseall,
Thanks for the reply -
How do I do that if the joists are cemented down into the blockwork and they end at the start of the void?
Cheers

 

[noseall]

Hi Noseall,
Thanks for the reply -
How do I do that if the joists are cemented down into the blockwork and they end at the start of the void?
Cheers

I'd start by removing those 3 or4 blocks visible.

 

[cdbe]

I'm not sure why you'd want to extend the joists - but always willing to learn!

Is that dpc supposed to be some kind of crude cavity tray? In which case it should finish pretty much where it does (inside of inner skin). I think I'd fill the void with expanding foam, being careful to put it either side of the dpc so it stays more or less where it is (if you Google "cavity tray" you'll understand it's purpose, and that it's probably there more as a continuation of the (hopefully) section protecting the brickwork either side of the openings). Cavity closers aren't a structural item - they're just foam and plastic - if you fill the void with expanding foam you could set a length of timber (something like a strip of that osb flooring) on top to finish flush with the flooring - it will be strong enough to carry the floor covering.

 

[noseall]

I'm not sure why you'd want to extend the joists

If this was built from scratch (and not retro-fitted), those blocks would not be there. Rather, the opening will have been trimmed out at floor level and the joists or some noggings attached to the joists, would have dived into that door reveal, in order to support the floor material, right up to the door threshold.

I like your drawing - but it's a bonkers remedy.

 

[noseall]

Is that dpc supposed to be some kind of crude cavity tray?

It is a standard cavity tray, and serves no useful purpose in that opening. I'd cut it and fit it against the external masonry, along with a wee bit of PIR, to thermally protect the single skin.