Advice on house with draughts

PerryB78

I'm in my house nearly 10 years and it's constantly draughty, I can feel air coming in under wardrobes and the floorboards upstairs. I have had external insulation installed, front wall pumped with expanding foam, new Windows, attic spray foamed and also the skirting boards removed and sealed under but despite all this it's still got draughts. I suspect their is a lack of or no wall plates, what can be done to remedy this? The house was a new build, thrown up at the height of the boom

MicktheMan

Your first port of call ought to be an air tightness test (possibly combined with thermal imaging) to highlight the air leakage paths. As proven to date, without knowing what is going on, you're wasting your money with so called "improvements".

listermint

PerryB78 wrote: »

I'm in my house nearly 10 years and it's constantly draughty, I can feel air coming in under wardrobes and the floorboards upstairs. I have had external insulation installed, front wall pumped with expanding foam, new Windows, attic spray foamed and also the skirting boards removed and sealed under but despite all this it's still got draughts. I suspect their is a lack of or no wall plates, what can be done to remedy this? The house was a new build, thrown up at the height of the boom

If there was not wall plates a cavity pump would have remedied the bulk of it.

As above you need a survey done so you can work with facts on next steps

PerryB78

listermint wrote: »

If there was not wall plates a cavity pump would have remedied the bulk of it.

As above you need a survey done so you can work with facts on next steps

We already got thermal imaging done which showed draughts coming in under most of the skirting boards, these were removed and expanding foam added. Since this was done the air seems to be funnelling in under the wardrobes in the main bedroom and under the floorboards. At the front of the house the draughts have been mostly eliminated but the coldness still emanates from the walls so I believe it's still getting in under the eaves and down through the walls, despite the front wall being pumped

PerryB78

Can the eaves be removed to check where the air is getting in and can they be still removed on the side and back of the house where the external insulation was done?

listermint

You should be able to check cavity caps from the attic space. I'd be surprised if the were not capped.

One thing I would do is ditch the expansion foam. It had its uses draught prevention isn't it.

You should be using airtight tape it's the only man for this job contega SL is the type of tape you should use.

PerryB78

listermint wrote: »

You should be able to check cavity caps from the attic space. I'd be surprised if the were not capped.

One thing I would do is ditch the expansion foam. It had its uses draught prevention isn't it.

You should be using airtight tape it's the only man for this job contega SL is the type of tape you should use.

The guys who spray foamed the attic said they had covered the cavity caps but I don't think they did as the draughts remain. The front wall was pumped as the insulation was fitted incorrectly and the front of the house was cold due to this, I hoped getting this done would also prevent air getting into the walls but it's still getting in

MicktheMan

You air tighten a building from the inside, not the outside (cavities are considered outside from an air tightness perspective). Expanding foam, as mentioned above, is next to useless for air tightness.

mp31

listermint wrote: »

You should be using airtight tape it's the only man for this job contega SL is the type of tape you should use.

Can I ask how you go about retrofitting airtight tape to the windows/doors of a house - is it a case of removing the plasterboard around a window, applying the tape and then re-applying new plasterboard before skimming and painting?

MicktheMan

mp31 wrote: »

Can I ask how you go about retrofitting airtight tape to the windows/doors of a house - is it a case of removing the plasterboard around a window, applying the tape and then re-applying new plasterboard before skimming and painting?

Yes and the airtightness tape on the window should be hidden by the new plaster / plasterboard.
The next question, of course, is how to air tighten the external walls (that you have just taped to) assuming they are bare block with some form of drylining:). If the external wall are leaking then taping the windows will have little impact. Remember, your airtight barrier needs to be continuous.

mp31

MicktheMan wrote: »

Yes and the airtightness tape on the window should be hidden by the new plaster / plasterboard.
The next question, of course, is how to air tighten the external walls (that you have just taped to) assuming they are bare block with some form of drylining:). If the external wall are leaking then taping the windows will have little impact. Remember, your airtight barrier needs to be continuous.

Interesting... where else on an external wall would there be air leaks apart from doors, windows and service boxes?
I'm assuming that any gaps in the cement used to lay the blocks are filled in by the external waterproof render.
Are first floor joists supported by making holes in the external wall - if so then I presume they also need to be taped?

What does it take to make an existing house (built c. 2000 out of hollow block internally insulated with rockwool) airtight?

the_pen_turner

What kind of heating have you and what ventilation is there in each room

MicktheMan

mp31 wrote: »

Interesting...
1. where else on an external wall would there be air leaks apart from doors, windows and service boxes?
2. I'm assuming that any gaps in the cement used to lay the blocks are filled in by the external waterproof render.
3. Are first floor joists supported by making holes in the external wall - if so then I presume they also need to be taped?
4. What does it take to make an existing house (built c. 2000 out of hollow block internally insulated with rockwool) airtight?

1. The wall themselves very often are poor (un-rendered on the internal)
2. Wrong. As stated earlier, you airtighten from inside, not outside.
3. Yes
4. It could be any number of things. This is why an air tightness test or heat loss survey is generally required to identify what exactly is happening.

mp31

MicktheMan wrote: »

1. The wall themselves very often are poor (un-rendered on the internal)
2. Wrong. As stated earlier, you airtighten from inside, not outside.
3. Yes
4. It could be any number of things. This is why an air tightness test or heat loss survey is generally required to identify what exactly is happening.

So just to clarify, does an air tightness test reveal the exact location of each leak from within the inside of the house i.e. during the test, is the air tightness assessor able to pinpoint the exact location of all major air leaks and chalk mark the plasterboard that sits above each leak?
This would allow the owner (or an appointed trades-person) to address each leak by removing a suitable section of plasterboard to expose the block wall, fix the leak and re-plaster.

MicktheMan

mp31 wrote: »

So just to clarify, does an air tightness test reveal the exact location of each leak from within the inside of the house i.e. during the test, is the air tightness assessor able to pinpoint the exact location of all major air leaks and chalk mark the plasterboard that sits above each leak?
This would allow the owner (or an appointed trades-person) to address each leak by removing a suitable section of plasterboard to expose the block wall, fix the leak and re-plaster.

Yes and no.
Yes, in that, the tester should be able to show where the air is entering the room, for example, under a section of skirting.
No, in that, the tester will not be able to say that the leak through the wall is behind that skirting board or plaster board above it. Hell, the block wall might not even be the culprit.
You must remember that air flow will take the path of least resistance depending on the air pressures present.

mp31

MicktheMan wrote: »

Yes and no.
Yes, in that, the tester should be able to show where the air is entering the room, for example, under a section of skirting.
No, in that, the tester will not be able to say that the leak through the wall is behind that skirting board or plaster board above it. Hell, the block wall might not even be the culprit.
You must remember that air flow will take the path of least resistance depending on the air pressures present.

Thanks for the info, it's very much appreciated.

To my mind, there appears to be very little value in an air-tightness test - it just indicates how leaky a house is but doesn't say exactly where the leaks are. If that's the case then how can I find and fix the leaks?

Sorry for sounding negative but what am I missing?

MicktheMan

mp31 wrote: »

Thanks for the info, it's very much appreciated.

To my mind, there appears to be very little value in an air-tightness test - it just indicates how leaky a house is but doesn't say exactly where the leaks are. If that's the case then how can I find and fix the leaks?

Sorry for sounding negative but what am I missing?

I'm assuming we're talking about an existing finished building. From experience, there are several values to the air tight test (att);
1. The appreciation by the client(s) of the magnitude of the problem.
2. With existing buildings, you are generally dealing with "compartmentalising" the air tight barrier per room; i.e. sealing room by room. The att will highlight what measures to use in each room. This is of course completely different to the approach to be taken in a new build situation.
3. Typically 4 to 6 high impact directly accessible leakages are uncovered during the att which can be readily addressed. This would be in addition to the smaller repeating indirect weaknesses found in each room.
4. I have yet to be told that "that was a waste of time". More often than not, the opposite;).

mp31

MicktheMan wrote: »

I'm assuming we're talking about an existing finished building. From experience, there are several values to the air tight test (att);
1. The appreciation by the client(s) of the magnitude of the problem.
2. With existing buildings, you are generally dealing with "compartmentalising" the air tight barrier per room; i.e. sealing room by room. The att will highlight what measures to use in each room. This is of course completely different to the approach to be taken in a new build situation.
3. Typically 4 to 6 high impact directly accessible leakages are uncovered during the att which can be readily addressed. This would be in addition to the smaller repeating indirect weaknesses found in each room.
4. I have yet to be told that "that was a waste of time". More often than not, the opposite;).

I guess in order to find (and subsequently fix) all the leaks in an existing house (in my case it's a house built in 1998, hollow block construction), the only way is to remove all the plasterboard first to expose all external walls and then do an air tightness test. This is expensive.

Alternatively, following the 80/20 rule, would you say 80% of the leaks are to be found around door and window openings?

If so, would it make sense, prior to the air-tightness test, to remove the surrounding plasterboard around all doors and windows and apply air-tightness tape. That way, you can make sure all your door/window openings are leak proof and any remaining leaks that are found are a bonus.

MicktheMan

mp31 wrote: »

I guess in order to find (and subsequently fix) all the leaks in an existing house (in my case it's a house built in 1998, hollow block construction), the only way is to remove all the plasterboard first to expose all external walls and then do an air tightness test. This is expensive.

Alternatively, following the 80/20 rule, would you say 80% of the leaks are to be found around door and window openings?

If so, would it make sense, prior to the air-tightness test, to remove the surrounding plasterboard around all doors and windows and apply air-tightness tape. That way, you can make sure all your door/window openings are leak proof and any remaining leaks that are found are a bonus.

You seem to be convinced that you have a problem with your windows & doors and are ignoring what I am trying to tell you; l.e. you won't know until your house is tested. And no, I wouldn't say 80% of leaks are from around the opes, not even close (probably closer to the 20% mark, but who knows).

mp31

MicktheMan wrote: »

You seem to be convinced that you have a problem with your windows & doors and are ignoring what I am trying to tell you; l.e. you won't know until your house is tested. And no, I wouldn't say 80% of leaks are from around the opes, not even close (probably closer to the 20% mark, but who knows).

No I'm not convinced about my doors/windows but suspicious. I'm just trying to understand why I can feel draughts around quite a few of our windows frames. The plasterboard around them is fitted very well and there are no gaps on the inside so I suspect that the frame/wall junction may be leaky.

Also, when I've cutout holes in the plasterboard for new sockets and for running cables for the electrician, I've noticed quite a draught behind the plasterboard - especially in the small bedroom upstairs. I'd like to remedy this sort of leak within the whole house.

I'm not ignoring anything. My 80/20 question was more about the general trend in air leaks.

You seem to be in the business of doing air tightness tests and if you are doing this a lot then I would have thought that there would be a trend that shows up over time e.g. most air leaks within a house are in locations X and Y or the leakiest houses are of type Z and so on. To me, this sort of data is valuable as it allows people to maximize the effectiveness of an air-tightness test.