I am working on an extension of an existing house and have difficulty making one wall seamlessly connect with the old wall in an aesthetically pleasing way. This could be resolved if I skip the air gap between the windproofing paper and the panel.
The walls are constructed as follows from the inside out:
Gypsum, chipboard, building foil, 45 mm insulation, 145 mm insulation, windproofing paper, (possible air gap), panel
The question is how important the air gap is—can one intentionally skip it and keep an eye on the wall, or is it extremely important for it to be there?
The walls are constructed as follows from the inside out:
Gypsum, chipboard, building foil, 45 mm insulation, 145 mm insulation, windproofing paper, (possible air gap), panel
The question is how important the air gap is—can one intentionally skip it and keep an eye on the wall, or is it extremely important for it to be there?
I think you should try to describe how your problem with assembling the wall looks, so perhaps you can get help here on the forum to maintain the air gap and solve the wall problem. (Or have you already "built yourself into a corner"?) The walls of mine that don't have an air gap I will gradually provide with one when the opportunity arises. It's harder for the panel to dry properly if it's not ventilated at the back, that's an undeniable fact. Wood paneling fares better the faster it can dry out after being damp. That's also a fact. Then there are surely 1000 small factors that affect how bad it is in your case. Clearly, it is best if you can find a solution to the wall problem, I think.
My problem is that I want both the outer wall and the inner wall to be at the same level for it to look nice. It is an extension of an existing wall. This means that the new wall must be as thick as the old one, and this is impossible with the amount of insulation I have chosen if I have the air gap, i.e., it will be 1 cm too thick if I have an air gap.
What is positive is that I have a large roof overhang, so it will be extremely rare for rain to fall on the wall.
What is positive is that I have a large roof overhang, so it will be extremely rare for rain to fall on the wall.
I can add that I had similar "issues" with my extension. I discovered during the construction that in the old part, there was 8 mm plywood + 10 mm gypsum in the outer walls. The new part was planned with 12 mm plywood + 13 mm gypsum.
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I tore off the gypsum on the old wall in the affected room. I covered the 8 mm plywood with 3.2 mm masonite and then re-gypsum the entire wall.
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I tore off the gypsum on the old wall in the affected room. I covered the 8 mm plywood with 3.2 mm masonite and then re-gypsum the entire wall.
That's a good idea, I've thought along the same lines, unfortunately it's already framed so that it matches on the inside, it's on the outside where it won't align. If I had discovered the problem earlier, it would have worked great to do so.Linnex said:
I've considered just adding 35 mm insulation on the outside, but then I'll probably have to shave off a cm from the boards since there is hardly any 35 mm insulation available.
Thank you so much for the help. The question is how important the air gap is. Should I invest the effort to take down the 45x45 battens and put up 35-battens and insulate thinner to make room for the air gap, or can I skip it with a clear conscience?Faidros said:
The rest of the house doesn't have an air gap, and I've never had problems with those walls, but you want to do it right.
I would probably guess that the old siding will give up before the new one in any case. So if you're not building too large, do what feels best now, and when it's time to re-side, it will be done according to the findings available at that time, both on the old part and the new one.
And for that matter, my house is built in exactly the same way. Siding without a gap directly on asphalt board. The house is 27 years old now, and the facade looks like it can last for many more years, and the north side still looks completely new. However, it's worse on the garage, and it will probably be necessary to replace the east and south sides in a few years.
And for that matter, my house is built in exactly the same way. Siding without a gap directly on asphalt board. The house is 27 years old now, and the facade looks like it can last for many more years, and the north side still looks completely new. However, it's worse on the garage, and it will probably be necessary to replace the east and south sides in a few years.
Thanks for your feedback, I will probably do as you suggest Linnex, and build the extension without an air gap on the side where the old wall continues, but with an air gap on the other walls. If I have to replace the cladding (no signs of it yet) I will fix the extension as well.
Just a small reflection, if the air gap is so important for the facade's wellbeing, then the north side should suffer the most from not having an air gap since the facade should have a harder time drying there than on the south side.
Just a small reflection, if the air gap is so important for the facade's wellbeing, then the north side should suffer the most from not having an air gap since the facade should have a harder time drying there than on the south side.
Many of the rules and recommendations that exist are general and based on different risk scenarios and currently known facts. This means that it is often possible to solve a construction both more simply and cheaply if one is aware of the risks/consequences and conditions for what one is going to build.
If you look back 50-60 years and the different recommendations that have existed during that time until today, it has turned out that many were completely unacceptable. In 5-10-20 years, we will be able to see that certain building techniques/materials from what exists today according to recommendation were wrong, and what has not followed recommendation/rules might still be functioning.
So your reasoning is entirely correct provided you are aware of what you are doing.
If you look back 50-60 years and the different recommendations that have existed during that time until today, it has turned out that many were completely unacceptable. In 5-10-20 years, we will be able to see that certain building techniques/materials from what exists today according to recommendation were wrong, and what has not followed recommendation/rules might still be functioning.
So your reasoning is entirely correct provided you are aware of what you are doing.