Is it possible to pressure test the wind shelter when the house is being built?

[Robert20]

I don't quite understand how you can create a shell that also includes floor and ceiling that can be tested since the only way is to pressure test.
If it is not yet insulated, you can see with a visual inspection that there are no holes/gaps in the outer diffusion barrier, both from inside and outside. And the final facade should also be included in the outer wind protection.

The walls are standing on a concrete slab, with some kind of rubber seal in between. Windows and exterior doors are taped. The interior ceiling and insulation are not in place yet, but the air gap just below the roof boarding is temporarily sealed to make the building dryers work more efficiently. The exterior walls are clad with outdoor gypsum with taped joints. Collectively, it SHOULD be airtight, but how can one know? You can't see inside and out everywhere, the frame structure obstructs vision, especially in the corners, and where there is an intermediate floor.

From what I've seen so far, I haven't seen anyone who knows how to check this. I would like a value for allowed air leakage per square meter of exterior wall.

 

[AndersS]

It's safe because there is no and complexity if you want to do it.
And based on the fact that the house's outer shell should not have that density.
The best is to ask KA, who should ensure that it is done correctly according to the applicable regulations.

 

[Robert20]

It is probably because it doesn't exist, and it's complex if you want to do it.
And considering that the house's outer shell shouldn't have that tightness.
The best thing is to ask the KA, who should ensure that it is done correctly according to current regulations.

Yes, but the wind barrier must be "tight," right? The question is just how tight? If there are no values ​​for wind tightness, it can blow through the insulation, as long as it doesn't get into the house.

Ok, I'll ask my KA.

 

[Installation]

Yes, but surely the wind protection must be "tight." The question is just how tight? If there are no values for wind tightness, it can blow through the insulation, as long as it doesn't enter the house.

Ok, I'll ask my KA.

it should not be tight. It should minimize air movement in the insulation. The plastic inside is the airtight layer. For passive houses, you have a leakage flow of 0.2-0.3 l/s/m2 somewhere.
If you pressure test against it, you will not have much tightness, and it will leak a lot /m2 at 50Pa overpressure, which is the pressure used for testing.

 

[Robert20]

it should not be airtight. It should minimize air movements in the insulation.
The plastic inside is the airtight layer.
If you pressure test against it, you will not have much tightness and it will leak a lot/m2 at 50Pa overpressure, which is what you test with.

Of course, I understand that it shouldn't be "vapor-tight." But without tightness values in the wind barrier, it could potentially be "completely open" and still be approved. That can hardly be the intention, as it would not be any protection against the wind. But I'm aware that it leaks much more than the vapor barrier.

 

[Installation]

Of course, I understand that it can't be "steam-tight." But without permeability values in the wind barrier, it could be "completely open" and still be approved. That can hardly be the intention, then it wouldn't be a wind barrier. But that it leaks much more than the vapor barrier, I understand.

And you won't get a reliable value. It's a completely unnecessary verification that doesn't provide anything. It should be performed according to the installation instructions, and it should be evident from self-checks. Trust me, I have participated in my fair share of pressure tests.

 

[Gabbe1]

I think the tone towards TS here is a bit too harsh.
In my world, the thinking is absolutely correct, wanting to have as tight a wind barrier around the frame/insulation as possible. Yes, it should be airtight, but not vapor-tight. Then the fact that it can be very difficult to achieve such pressure testing (of only the wind barrier) is another matter.

 

[AndersS]

Of course, I understand that it shouldn't be "steam-tight." But without density values in the wind barrier, it could be "completely open" and still be approved. That can hardly be the intention, as it wouldn't be any wind protection. But I am aware that it leaks much more than the vapor barrier.

Yes and No, it depends on what the manufacturer has designed and promised, as well as how the construction is done and if it follows any regulations. But also on the choice of product and how it should be installed according to that manufacturer. For parts of a construction, visual inspection can be sufficient and in many cases the only method to verify correct execution. A "wind protection" should prevent wind from blowing in from the outside, so in theory, actually even in practice, I can construct one that has greater permeability from the inside than the outside.

 

[Robert20]

Yes and No, it depends on what the manufacturer has designed and promised, as well as how the construction is done and if it follows any regulations. But also the choice of product and how it should be mounted according to that manufacturer.
For parts of a construction, visual inspection may be sufficient and in many cases the only method to verify correct execution. A "wind barrier" is supposed to prevent wind from entering from the outside, so in theory, actually also in practice, I can design one that has greater passage from the inside than the outside

Sounds interesting. Do you mean that one could design the wind barrier as a "check valve" that lets out vapor but doesn't let it in? Tell me more.

 

[Installation]

It is outdoor drywall with taped joints. This may provide 0.8-1l/s/m2 at 50Pa overpressure. What I mean is that if you want to pressure test, keep in mind that the nailing boards should be on the outside so you don’t push the drywall out. It will be 10-12 kg per sheet outwards. You will also get quite a large uncertainty factor in the pressure testing. Personally, I would recommend insulating and sealing the inside so it is airtight. Then pressure test with both over and under pressure and perform thermography. That way you can see any exact leaks. It usually is electrical conduits and vents that leak. Remember that all drains must be sealed. Water in wells and lids on all ends, etc. If the unit is installed, you must either use balloons in the outdoor air/exhaust air or tape the hoods. The intake channel as well. It costs a few bucks to pressure test an extra time. Verifying it is part of the contractor’s obligation, unless they have written it off to the customer. But it will appear somewhere. A pressure test can, if everything is optimal, cost around 10-15000 SEK perhaps. If it is not airtight and requires extra work, the cost will increase significantly. Maybe not if you just check the windbreak since it is inherently leaky. However, the uncertainty factor will increase, indicating that something is leaking somewhere. If you use under pressure in the winter, it’s easy to see where cold air is leaking in and sealing can be done. However, the contractor is likely to charge extra if they have followed the manufacturer’s instructions, etc. What I mean is that the cost of 10,000 SEK can easily take 25 years to pay back with the increased heating costs. Assuming the vapor barrier is ok.

 

[Robert20]

It is outdoor gypsum with taped joints. It might provide 0.8-1l/s/m2 at 50Pa overpressure. What I mean to say is, if you want to perform a pressure test, keep in mind that the nail boards should be on the outside to avoid shooting out the gypsum. That will amount to about 10-12 kg/sheet outward.
You'll also end up with quite a significant uncertainty factor in the pressure testing.
Personally, I would recommend that you insulate and apply plastic on the inside to make it airtight. Then, perform the pressure test with both over and underpressure and use thermography. This way you can see any potential leaks exactly. It’s usually electrical conduits, vents that leak. Remember that all drains must be sealed. Water in wells and covers on all ends, etc. If the unit is installed, you need to place either balloons in outdoor air/exhaust air or tape the hoods shut. The inlet channel as well.
It costs a few bucks to do an extra pressure test. Verifying this is part of the contractor's commitment unless they have excluded it to the customer. But it’s specified somewhere.
A pressure test could, if everything is optimal, cost around 10-15,000 bucks perhaps. If it’s not airtight and extra work is required, the costs can increase significantly. Maybe not if you just check the wind barrier since it is not airtight itself. However, the uncertainty factor will increase and it will show that there is leakage somewhere. If you do an underpressure test in winter, it is easy to see where cold air is seeping in and sealing can be done. However, the contractor will likely require extra work on the spot if they have followed the manufacturer’s instructions, etc.
What I mean is that the cost of 10,000 SEK can easily take 25 years to pay back with the increased heating cost. Assuming that the vapor barrier is okay.

Thank you for the informative response. This thermography must be a better way than measuring leakage values in absolute terms. Then you should be able to find the defects. It would feel reassuring to know that you’ve done what you can.
(That it costs money to pressure test, I understand, and in my case, also to fix, since my builder works on an ongoing basis.)

 

[AndersS]

Sounds interesting. Do you mean that you could construct the windbreak as a "check valve" that lets out steam, but doesn't let it in? Tell me more.

I have an older additionally insulated house, and the windbreak lies in the attic on top of the insulation without being attached. Perhaps not applicable to a new house but still an example.

 

[Installation]

Thank you for an informative answer. This thing with thermography must be a better way than measuring leakage values in absolute terms. Then you should find the defects. It would feel good to know that you have done what you can.
(I understand that it costs money to pressure test, and in my case also to remedy, since my builder works on a running basis.)

thermography is pretty pointless without pressurization.

 

[Installation]

Now I have an older additionally insulated house and the wind barrier is on the attic above the insulation without being attached.
Maybe not applicable to a new house but still an example.

It's not super important for it to be airtight.

 

[AndersS]

It's not super important that it is windproof.

You should probably quote ts instead from the dialogue. It's not me who wants to test the tightness in the shelter.