Cold breeze through sockets

[Murph1603]

Hi Guys looking for some info/help here, just finishing up a self build and the insulation spec was 120mm PIR inside the kit with 25mm PIR over the kit with all joints tape, but we’ve noticed during windy days we’ve wind coming through all outlets on external walls, the outside of the house is concrete blocks which haven’t been scratched yet or rendered, would it be possible that the wind is coming in through the expansion joints/around windows,sills and doors that haven’t been sealed and getting through the kit? We put the 120mm in as tight as we could and any small gaps were fill with expanding foam. Any help appreciated guys thanks 

[ProDave]

Looking at that picture, how are the cables getting into the service void? (the gap between the PIR and the plasterboard?  It looks like they are coming up from under the floor in that picture.  That will be one source of cold draughts.  Likewise I bet lighting cables are going up through the ceiling into the cold loft space and that is another source of cold air getting in.

 

As an electrician, I have come to expect this sadly as "normal" when you remove a socket on a windy day, and icy cold draught comes out of the back box.

 

What stage are you at?  and who has been advising you?  If you read the forum there is a lot talked about attention to detail, and that is what has let you down.

 

EDIT: looking at the picture again, is that a service void I am looking at, or is that the frame with the insulation between studs before the over sheeting insulation went on?  If so you have created a cold gap between the insulation layers.

[Kelvin]

Doesn’t this ultimately come down to where you put the air tightness layer, then the careful detailing of that. We also designed our service void so that there’s an uninterrupted horizontal run around the rooms. This also has the advantage of being easy to add other sockets in future. 

My electrician commented that ours is one of the first houses he’s worked in where there’s no cold draughts behind the back boxes. I would have been incredibly disappointed had there been to be honest. 

Edited December 26, 2023 by Kelvin

[ProDave]

Until the OP replies I suspect there is no air tightness layer apart from the taped top layer of PIR that has lots of holes in it for cables.

 

Perhaps when the OP answers he can tell is what air tightness details have been used, what about under the floor and in the loft (assuming it is a normal cold loft)?

[nod]

I would make a baffle box out of pb for each socket to sit in 

Im presuming that the walls are being counter battened 

[Murph1603]

So there is 120mm in the kit then a 25mm service gap then 25mm PIR over the kit, the house is unfortunately taped and painted now as nothing was noticed in summer months we never knew anything was wrong, we were spec’d either 120mm PIR in the kit or 140mm Frametherm and went for the PIR as it worked out a lot cheaper, is there anything we can do to rectify this?  Also about the ceiling is 400mm of mineral wool and below the floor is 200mm of mineral wool, air Tightness test was done and came in at 1.62 Appreciate the help 

Edited December 26, 2023 by Murph1603

[ProDave]

Who specified and built the frame?  What air tightness did they expect to achieve?

 

Having the service void in between insulation layers is just plain wrong.  Whoever specified that needs "educating"  Every single hole into that space, for cables etc, will be allowing cold air into that service void, virtually negating the insulation of the 120mm if PIR between the frame members.  So if you are going to do it that way, then sealing the living daylights out of every single cable penetration is required.

 

I suspect the best you can hope for now to improve it is go into the loft, roll back the insulation all around the edges and seal the living daylights out of every single hole where cables come up into the loft.  This will apply to cable drops down into the (probably non load bearing) partition walls between rooms as well.  It is probably too late to do anything about the (hopefully fewer) cable penetrations down into the sub floor space downstairs.

 

What about plumbing?  Are there also pipes going up into the loft or down under the ground floor?

[Murph1603]

I will try and foam up any and all penetrations into that areas, no plumbing work in any external walls, can get below the floor quite easily and will go down and try and foam these areas also, truth being maybe we were bit Naive in our abilities and not knowing enough about insulation, we’re in a situation now where I think it’s a struggle to heat this place and my girlfriend is due to give birth in 3 weeks and don’t think we can raise a kid in a house that is this cold.

[ProDave]

What heating system?

[Mr Punter]

You are doing the right thing going around with a foam gun and perhaps some decent tape.  Look out for boiler and extract holes, overflows, condense drains etc.  Trades very rarely make good around these.  Bear in mind that not every day will be cold and windy, so you may find it performs OK for much of the year.

[Murph1603]

52 minutes ago, ProDave said:

What heating system?

Oil boiler 

[Murph1603]

2 hours ago, Mr Punter said:

You are doing the right thing going around with a foam gun and perhaps some decent tape.  Look out for boiler and extract holes, overflows, condense drains etc.  Trades very rarely make good around these.  Bear in mind that not every day will be cold and windy, so you may find it performs OK for much of the year.

Thanks, there’s nothing from the inside going outside through the kit, the boiler is external and ducted in under the house, most days are windy in the far north of Scotland but I Appreciate the sentiment all the same 

[ProDave]

2 hours ago, Murph1603 said:

Oil boiler 

Radiators?  Under floor heating?

 

I can imagine the draughts through the sockets being annoying, but I would be surprised if that is the reason an oil boiler is struggling to keep the house warm.

[Redbeard]

Make sure you use *Airtight* foam. Illbruck FM330 is what I use, but Soudal (and probably others) do one too. Not all foam is air-tight.

[MikeGrahamT21]

On 26/12/2023 at 14:52, Redbeard said:

Make sure you use *Airtight* foam. Illbruck FM330 is what I use, but Soudal (and probably others) do one too. Not all foam is air-tight.

I believe it’s name is visco-elastic polyurethane foam

[Murph1603]

On 26/12/2023 at 14:34, ProDave said:

Radiators?  Under floor heating?

 

I can imagine the draughts through the sockets being annoying, but I would be surprised if that is the reason an oil boiler is struggling to keep the house warm.

It’s radiators, my thinking being if the air is running up behind the 25mm insulation then effectively I’ve very little insulation acting on my external walls, we had 70mph winds here today and the air was howling in with the gusts might be a reach but would air getting in through expansion joints and missing sills be roaring in through the kit and making its way in? I’m half hoping that once house is scratches coated, rendered and all sealed up it may stop the air so much as the externals will be sealed as such,