Void Behind Bay Window Roof - How bad of an issue is this?

[EinTopaz]

Hi all,

 

Was recently looking at replacing the soffits and facias over a front bay window, on closer inspection It looked like there was potentially a void in the outer skin of the wall that the soffits, facias and the roof of the bay window are covering.

I decided to take some tiles off to have a better look and did indeed find a void in the outer skin of the wall, and to my eyes looks like the void continues through the inner skin too? (though it'd be good for someone to confirm that). Based on the image and video below, how bad of a problem is this? should I get the roof off and seal this void? Reason I ask is because this bay window is for the dining room, notably the coldest room in the house. So perhaps not a coincidence?

 

 

Here's a video that shows the void well :- Hole Video Behind Bay

 

And images too:- 

 

Bay window in question 

 

 

 

 

Void behind the tiled roof.

 

 

 

 

What do you guys think? fine? or bad? or really bad?
 

thanks

 

Ged

Edited Monday at 16:47 by EinTopaz

[Nickfromwales]

The internal leaf of masonry should be a continuous ‘layer’, so draughts can only travel through the cavity. 
 

What we’re seeing is typical ‘builder quality’ work for that era.  

[Tony L]

3 hours ago, Nickfromwales said:

...typical ‘builder quality’ work for that era

 

& the current era as well, if the builders & architectural technicians I have employed are representative of today's building industry personnel.

[EinTopaz]

thanks guys. It looks to my eye that neither of the leafs are continuous based on that.... and looks like they'd foamed the outer once but either not all the way across or its failed.

 

For a fix, tiles, battens, felt off.... PIR board wedged in as deep as I can get it, and foam sealed around the edge, will that suffice?

 

 

For trivia....Worth noting the property used to be a bungalow so those bays will have originally just run into the old roof. It was converted in 2006 so had hoped i wouldn't be finding this but hey ho, it is it what it is. 

 

picture of it in its original bungalow form...

 

[Mr Punter]

If it was done in 2006 there may be some drawings.  You would think there would be a beam or lintel spanning above the window to support the masonry for the new first floor.

[EinTopaz]

There likely is, but i think it may be even higher up than this, Every bedroom on the 1st floor of this property steps up 100mm towards the front of the house, so I reckon the lintel is in there. All the voids between floor and ceiling have double cavity voids too. Where I think they kept the original bungalow ceiling up, then essentially did another cavity above that. Its an odd one.

But either way; is the fix to basically PIR board that huge gap and foam seal?

 

 

[Super_Paulie]

2 hours ago, Mr Punter said:

If it was done in 2006 there may be some drawings.  You would think there would be a beam or lintel spanning above the window to support the masonry for the new first floor.

looks like a catnic to me?

Id do what you suggest, PIR in there, foam it in and then cover with wool where you cant get to it. Probably not worth using thermalites if the lintel is supported which it surely is.

[Nickfromwales]

1 hour ago, Super_Paulie said:

looks like a catnic to me?

Id do what you suggest, PIR in there, foam it in and then cover with wool where you cant get to it. Probably not worth using thermalites if the lintel is supported which it surely is.

What he said. 
 

Just use FM330 foam, as that wont bridge damp etc. 

[EinTopaz]

thanks guys, how much of a problem is it if i can only get the PIR closing the outer leaf rather than the inner? Im not sure how good the access will be without removing the entire roof. Which ofcourse i'd rather not. 

 

 

[Nickfromwales]

5 minutes ago, EinTopaz said:

thanks guys, how much of a problem is it if i can only get the PIR closing the outer leaf rather than the inner? Im not sure how good the access will be without removing the entire roof. Which ofcourse i'd rather not. 

 

 

Inner for draught proofing, or you’ll still have a cold room. 

[EinTopaz]

12 minutes ago, Nickfromwales said:

Inner for draught proofing, or you’ll still have a cold room. 

where else would the draughts be coming from? 

[Mr Punter]

It does look a lot better as a house than a bungalow.

[EinTopaz]

Just now, Mr Punter said:

It does look a lot better as a house than a bungalow.

thanks, Perhaps only on the surface... been 5 years of finding horrendous workmanship. I feel we're finally at the end of it now (he says)

[Nickfromwales]

16 minutes ago, EinTopaz said:

where else would the draughts be coming from? 

The cavity

[Super_Paulie]

If you've ever stripped old walls then you'd be surprised how drafty it is through any gap between bricks on the inner wall. Id imagine there's wind howling round cavities so you've got to do your best to stop that, I tend to just rake out and repoint but I do use FM330 if it's easier to do so.

[EinTopaz]

We are replacing the soffits and facias on the top floor this summer, so I guess i'll have a look at how exposed/unsealed the tops of the wall cavities are then. 

[Nickfromwales]

8 hours ago, EinTopaz said:

We are replacing the soffits and facias on the top floor this summer, so I guess i'll have a look at how exposed/unsealed the tops of the wall cavities are then. 

The cavity must remain open, but only open to atmosphere.