Wind blowing through drylined walls

vidapura

Apologies for the uninformed nature of this question.

90s bungalow.
Cavity walls.
Drylined inside, presumably in 90s, so insulated plasterboard not used, so there is an airgap between brick wall and plasterboard.

Main cavities (between bricks) were pumped with beads at some stage.

---

Then I bought the house... and I feel its cold.

I pulled a socket out of the bedroom wall (exposing gap plasterboard between plasterboard and brick) and there's a noticeable draft blowing out of the hole.

Four Questions:

1 - should there be air blowing along in the inside drylined cavity?

2 - do I really need drylining if the main cavity is pumped with bead?

3- is my suspicion that the air moving through behind the plasterboard is sucking the heat out of the room a valid one?

4 - Should I seal it (cap it?) from the top in the attic or do I risk creating some other problem?


Thanks

Metric Tensor

1. No
2. If it was not insulated board it was never any use anyway.
3. Yes
4. Rip it all down and plaster the walls with two coats of sand and cement screed and a skim finish. Also consider air tightness details at opes, joints, etc.


Most likely considering the age of your house the entire wall is porous due to minimal mortar in joints, poor detailing, etc. Pumping the wall should have partially reduced the flow of air through the wall but that's not its job - just a side effect - so you may have major leaks elsewhere.

Also this free movement of air in the gap inside the insulation is making your pumped insulation useless!

Metric Tensor

P S. You could also pull down the dry-lining, put up an airtight membrane and them put the dry-lining back up .... if you want .... I wouldn't do it that way myself though.

I just noticed you said "cap it at the attic" - is this void open in to the attic? That could change things a bit.

tedimc

Is there much of a gap between the board and the brick wall?

I wonder if you could pump the gap from the inside? Maybe with something like walltite foam?

Would give you the air-tightness, stop drafts and provide some level of insulation based on the width of the gap. Patching the holes would be a pain though. May be worth trying one room and see how it works out.

vidapura

Metric Tensor wrote: »

P S. You could also pull down the dry-lining, put up an airtight membrane and them put the dry-lining back up .... if you want .... I wouldn't do it that way myself though.

I just noticed you said "cap it at the attic" - is this void open in to the attic? That could change things a bit.

I'm not certain.. it somethin someone suggested I check...I have to dig through layers of glass fibre to see.. I could only find time for a quick look tonight and all I could see was what I think is the ceiling board covering right over to the wall.

There are vents in the outside wall (seen from outside the house).. would the wind be blowing in that way?
Would they be the "major leaks somewhere" you mentioned?

Thanks for your responses.. I did suspect that the air moving inside the drylining was undoing all the good of the pumped cavity..

vidapura

tedimc wrote: »

Is there much of a gap between the board and the brick wall?

I wonder if you could pump the gap from the inside? Maybe with something like walltite foam?

Would give you the air-tightness, stop drafts and provide some level of insulation based on the width of the gap. Patching the holes would be a pain though. May be worth trying one room and see how it works out.

Walltite is very interesting alright.. would that be safe with electrical wires .. overheating and all that?

tedimc

vidapura wrote: »

Walltite is very interesting alright.. would that be safe with electrical wires .. overheating and all that?

I recall something about there being a question around how the foam would affect the cable insulation when it is curing (10-15 minutes after being pumped in). But I never got a clear answer to this.

You would need to check with an electrician to see what spec cable is there as the insulation would definitely reduce the safe current carrying capacity.

However, based on their feedback - it could be still worth considering as it would only be for the last few feet of cable (presuming the majority ran under the floor, in the attic, etc;) and I would think it would have minimal impact overall.

BryanF

tedimc wrote: »

I recall something about there being a question around how the foam would affect the cable insulation when it is curing (10-15 minutes after being pumped in). But I never got a clear answer to this.

You would need to check with an electrician to see what spec cable is there as the insulation would definitely reduce the safe current carrying capacity.

However, based on their feedback - it could be still worth considering as it would only be for the last few feet of cable (presuming the majority ran under the floor, in the attic, etc;) and I would think it would have minimal impact overall.

Do you have shares in this company?

OP do not use this product unless you get an independent professional PI covered opinion on site

Metric Tensor

The vents you see outside OP - assuming they're the standard room vents (4-6 inch round hole with a square or round cover) - they should go right through the entire wall including into the room inside. If they have been dry-lined over this is definitely wrong.

They should be sealed in such a way that they only connect the outside environment directly to the inside of the room. They shouldn't allow air into or out of any cavities they pass through.

vidapura

Metric Tensor wrote: »

The vents you see outside OP - assuming they're the standard room vents (4-6 inch round hole with a square or round cover) - they should go right through the entire wall including into the room inside. If they have been dry-lined over this is definitely wrong.

They should be sealed in such a way that they only connect the outside environment directly to the inside of the room. They shouldn't allow air into or out of any cavities they pass through.

Ahh haa.. now thats interesting .. cos it occurred to me this morning that there are no visible vents inside the room.... the walls in the rooms are flat .. featureless.. no openings..

So the vents musta been drywalled over...

Can I block the vents?
Are they necessary at all?

These are bedrooms I'm talking about now.. no fireplaces or stoves in them..

I notice also that the inner brick wall inside the drywalling is unrendered...
As in, when I took the socket out for a gawk I see no plastering .. just raw brick...
So the drywall must have been done when the house was built right?

vidapura

BryanF wrote: »

OP do not use this product unless you get an independent professional PI covered opinion on site

Yessir.. was thinkin that I'd need to get pro oversight before I do anything anyway..

tedimc

BryanF wrote: »

Do you have shares in this company?

OP do not use this product unless you get an independent professional PI covered opinion on site

ha ha- I was waiting for that to be mentioned as I have been talking about it quite a bit lately.

Unfortunately, I don't - my mortgage repayments would be a hell of a lot easier if I did...

I just thought I'd mention it as an option to look into. TBH - I would suspect that any of the installers wouldn't do it anyway as:
1 - they couldn't guarantee that the plasterboard wouldn't belly/bust
2 - there would be too much work patching the holes left behind inside in order to leave them all in a reasonable state.

Metric Tensor

Do not block the vents - extend them into the rooms (if they are the right type of course - what do they look like outside?).

It's a very cheap starting point. Then see if there's a much air movement behind the boards.

As for the rendering - that's why my original suggestion was to pull down the dry-lining and render the walls. The walls are a potential point for air to move in and out of the dwelling - albeit less so since the cavity was pumped.

And yes it was almost certainly done as the house was being built but I can't fathom why the vents weren't done correctly at the same time - which leads to my question in brackets - maybe we are talking about different types of vent!

tedimc

Metric Tensor wrote: »

And yes it was almost certainly done as the house was being built but I can't fathom why the vents weren't done correctly at the same time - which leads to my question in brackets - maybe we are talking about different types of vent!

Would the old walls not have been picked back at some stage over the years -removing the original plaster/render?

Then to stop dampness, someone thought it would be best to dryline?

Metric Tensor

House was built in the 1990s - I think it was probably never plastered.

It's a style I've seen particularly for 1970s and 80s houses a bit. Some sort of idea that plasterboard and skim was cosier (probably also cheaper).

In terms of air-tightness they are pretty much the worst houses in the country - I was at a course a few years back and someone (not sure who) had done a survey and they absolutely p!ssed out the air.

tedimc

Metric Tensor wrote: »

House was built in the 1990s - I think it was probably never plastered.

It's a style I've seen particularly for 1970s and 80s houses a bit. Some sort of idea that plasterboard and skim was cosier (probably also cheaper).

Oh yeah - missed the 90s bungalow bit in the OP. With the talk about bricks I was thinking an old red brick house from the turn of the century.

Metric Tensor

I'm assuming he meant blocks but wrote bricks!

vidapura

Metric Tensor wrote: »

I'm assuming he meant blocks but wrote bricks!

Heh, sorry, as I said at the start.. this is a very uninformed question from my side..

I think I did mean blocks indeed.. not bricks.. my apologies...

As for what type of vents they are.. ehh .. they look a bit like this one but it looks like you can slide em open or closed...



https://2ecffd01e1ab3e9383f0-07db7b9624bbdf022e3b5395236d5cf8.ssl.cf4.rackcdn.com/Product-800x800/de6528d1-76a9-4baa-b93b-ab130bbe269e.jpg

vidapura

tedimc wrote: »

Would the old walls not have been picked back at some stage over the years -removing the original plaster/render?

Then to stop dampness, someone thought it would be best to dryline?

Ehh well.. If it was picked back they did a very careful job of it.. its clean as a whistle in there..


If I get time tonight I'll take the socket off the wall again and get a photo with a little inspection camera...

Metric Tensor

That's a picture of what you should have on the inside wall ... there wouldn't be a slider on the external wall of the house .... or at least there shouldn't be!!!

vidapura

Metric Tensor wrote: »

That's a picture of what you should have on the inside wall ... there wouldn't be a slider on the external wall of the house .... or at least there shouldn't be!!!

Ehh.. well its not on the outside wall anymore.. fell right off when I tried to close the slider...

Stupid yoke..

And what was I left with when it fell off??.. well.. peer into me hole here:

https://goo.gl/photos/kUpAeKAGDvHp33tn8

Looks like a pipe going through the two leaves of brick and gap (which is pumped) and ending in behind the plasterboard...

Now there's two other vents like this on the gable end .. so I'm going to have a look at them all next time I can get home in daylight.. (Saturday I'd say)

Thinkin I better close this one up some way before something builds a nest in it..

Metric Tensor

Buy a new external vent cover to cover it up. You are correct that nests will appear if left open!

I'm only looking at the picture on my phone but it seems like there is some leakage of bead into the vent - it's difficult to know what path it took to get there!

Is that some sort of mortar/plaster "snot" I see? Either way that vent should penetrate to the room inside.

vidapura

Metric Tensor wrote: »

Buy a new external vent cover to cover it up. You are correct that nests will appear if left open!

Yep.. thats what I'm thinkin.. but not sure will I just expando foam it and close it up properly.

Metric Tensor wrote: »

I'm only looking at the picture on my phone but it seems like there is some leakage of bead into the vent - it's difficult to know what path it took to get there!

No, I don't think thats bead.. it looks like aeroboard behind some of the plasterboard..

Metric Tensor wrote: »

Is that some sort of mortar/plaster "snot" I see? Either way that vent should penetrate to the room inside.

You;d think wouldn't you?
Yah that "snot" looks like it was mortar/filler applied from inside the room before the plasterboard went up..

Now this vent is not the vents that I really want to get a look at .. there's two others that I think are freezing the end bedrooms..
So stay tuned.. I'll have photos of whats in them at the weekend..

Metric Tensor

Don't fill in the vents .. you should be doing the exact opposite and opening them up properly. Houses need ventilation and in the absence of a HRV system the hole in the wall is the only show in town.

The snot my be a mortar "dab" depending on the way the board was applied to the wall.

Is the plasterboard insulated on the back throughout?

It seems to me, from what you have described, that the blockwork was built and the appropriate vents left in the wall but that the guy doing the slabbing didn't bother his ar5e doing the right thing and completing the vent. Instead he just whacked up the board over it!

Anyway - tldr: - DON'T block the vent. Extend it into the room.

It won't solve your air leakage issue but if you ever solve the air leakage issue you'll need to have the vent!

vidapura

Metric Tensor wrote: »

Is the plasterboard insulated on the back throughout?

I don't think so.. but I shoud have time at the weekend to get me hole camera in there for a good look..

Metric Tensor wrote: »

It seems to me, from what you have described, that the blockwork was built and the appropriate vents left in the wall but that the guy doing the slabbing didn't bother his ar5e doing the right thing and completing the vent. Instead he just whacked up the board over it!

Yep, so it would appear.
Twill be really interesting to see what the story is with the other two vents.
The ones in the actual bedroom...

Metric Tensor wrote: »

Anyway - tldr: - DON'T block the vent. Extend it into the room.

It won't solve your air leakage issue but if you ever solve the air leakage issue you'll need to have the vent!

Tis hard to resist.. the bedroom was freezing last night .. sub 16C...

But this morning there was major condensation on the window.. so we need some sort of venting alright..

Can they be made one-way at all? Like a valve..
Wouldn't mind air getting out .. its just when the wind blows cold air in ... sigh..

Fayre

Blocking up the vents could give issues with mould inside. The vents aren't your problem if you sort out the big issues like insulation and plastering the walls. Plenty of houses have wall vents and can be kept cosy and warm in winter.

Metric Tensor

As Fayre says - the vent is not your problem - it actually should be part of your solution!!

Plastering your walls is probably the solution but it's going to be expensive! An appropriately fitted airtighness membrane would also do the job but that would be no cheaper.

To start with though have a look at your windows and doors to see if they are draughty. Fixing that in an interim manner might help a little bit.

Are you certain the cavities of the wall are pumped?

vidapura

Metric Tensor wrote: »

Are you certain the cavities of the wall are pumped?

Well, the beads are visible around the place. In the ESB meter box etc.
And I see faint round mark in the gable end walls that would suggest it too..

I will try to figure out how to get at an outside wall to look down but its difficult..

Metric Tensor

The reason I ask is that if the walls were leaky pumping it with bonded bead should reduce the leakiness quite a bit.

The bead is in no way designed for air-tightness purposes but by virtue of the cavity being full rather than empty there should be less air movement - it makes the massive draught behind your dry-lining a little harder to explain.

MicktheMan

Metric Tensor wrote: »

The reason I ask is that if the walls were leaky pumping it with bonded bead should reduce the leakiness quite a bit.

The bead is in no way designed for air-tightness purposes but by virtue of the cavity being full rather than empty there should be less air movement - it makes the massive draught behind your dry-lining a little harder to explain.

Have to disagree with this. Bead in a cavity makes no discernible difference to airtightness.

Metric Tensor

I'll take your knowledge on it Mick because mine is limited and only anecdotal. I have no measured values of pre and post pumping air tightness.

So it could still be the wall OP!