We are busy working on the upper and lower hall and the stairs. We have now removed the stairs to sand them properly and repaint. Now that the floor is completely free from obstacles, the plan is also to tear down to the concrete and remove the embedded treated studs, so that's done too. However, we've hit a bit of a dilemma. The house was built in '69, so we've got proof that the current risk construction is up to standard. BUT, the house is damn 52 years old; at some point, it has to be replaced, even if it has been a winning concept.
Currently, it is: Slab, embedded studs, wool and construction debris, air gap, floor chipboard.
Under the built-in closets in the hall, it's open down to the foundation, with ventilation holes at the bottom of the closets. I assume that's to ventilate the slab? There we could measure approximately 15-16cm to the top of the floor chipboard. The plan is then to have: Slab, air gap of 4-6cm, C24 45x95 studs with plastic screws like subfloor/level with suitable insulation board between the studs, floor chipboard. I can imagine that's somewhat under-dimensioned, but there isn't much more space to work with.
In our view, the slab should then be ventilated even better with this method compared to when the insulation lies like a flat pancake directly on the slab as it does now? BUT, are we disturbing a functioning method? Does the wool today act as a lid against the slab and keeps moisture away? The last thing we want is to replace the treated studs with a mold problem instead. The slab is uninsulated.
It's a bit ''urgent'' since I'm off for a week starting today, hoping that even the lower hall would be completed during this period. It wasn't until we stood here in our empty hall that we thought, now is the best time to tear everything up instead of later with the stairs back in place... Of course, this should have been planned better, but it obviously wasn't.
I'll include some pictures, the one where you see the entire slab is the neighbor's house from kitchen renovation that started last week; we live in identical houses. The rest of the pictures are from the hall and under the closet where you can see the slab and an embedded stud.
Currently, it is: Slab, embedded studs, wool and construction debris, air gap, floor chipboard.
Under the built-in closets in the hall, it's open down to the foundation, with ventilation holes at the bottom of the closets. I assume that's to ventilate the slab? There we could measure approximately 15-16cm to the top of the floor chipboard. The plan is then to have: Slab, air gap of 4-6cm, C24 45x95 studs with plastic screws like subfloor/level with suitable insulation board between the studs, floor chipboard. I can imagine that's somewhat under-dimensioned, but there isn't much more space to work with.
In our view, the slab should then be ventilated even better with this method compared to when the insulation lies like a flat pancake directly on the slab as it does now? BUT, are we disturbing a functioning method? Does the wool today act as a lid against the slab and keeps moisture away? The last thing we want is to replace the treated studs with a mold problem instead. The slab is uninsulated.
It's a bit ''urgent'' since I'm off for a week starting today, hoping that even the lower hall would be completed during this period. It wasn't until we stood here in our empty hall that we thought, now is the best time to tear everything up instead of later with the stairs back in place... Of course, this should have been planned better, but it obviously wasn't.
I'll include some pictures, the one where you see the entire slab is the neighbor's house from kitchen renovation that started last week; we live in identical houses. The rest of the pictures are from the hall and under the closet where you can see the slab and an embedded stud.
Construction veteran
· Norrland
· 342 posts
Hey! Yeah, it's probably a good idea to take out the studs if you're going to open it up anyway. But it might not actually be necessary, only you can decide that. However, if you do open it, it's probably best to remove the embedded studs and do as you said with the subfloor/leveling. It's definitely not under-dimensioned; rather, it's over-dimensioned. When we lay leveling or subfloor at work, it's almost exclusively 45x45, and often we have to rip them down to even thinner in certain places due to pipes and other things. Surprisingly little stud is needed, but maybe you'll need to add an extra plastic screw. The floor will definitely be better ventilated than it is now. But if you go with leveling/subfloor, you must either have ventilated skirting boards or alternatively an exhaust fan (in that case, you need ventilated skirting boards for air supply).
Thanks for the response!S Snickarkirre said:
Nice that you're a carpenter too, feels reassuring so we're satisfied with 45x95 then. But why do you need ventilated baseboards when using nivell or similar systems? Is it simply to help moisture escape from the foundation, or is it a necessity with this type of installation? It feels like more crawlies and "insulation smell" would come up with ventilated baseboards.Better crawlies than mold, so if we go with ventilated baseboards, do we simply leave a small gap between the floor chipboard and the wall so the air can get down under the insulation?
Called and talked to a nice gentleman at the construction advisory service via the home insurance. He also understandably thought that Nivell and others are the saviors in times of need. But when I asked about the warm indoor air going down into the ventilated floor and meeting the cold slab, wouldn't that cause condensation and become damp? Then he became unsure... Because yes, it does sound like that could happen. But then he said that this is how it's supposed to be done, so it should work...
Doesn't anyone else think that warm indoor air going down onto a cold slab should result in higher humidity?
Doesn't anyone else think that warm indoor air going down onto a cold slab should result in higher humidity?
Construction veteran
· Norrland
· 342 posts
Do you have any other ventilation in the foundation and do you have problems with moisture in the slab? If you don't have any ventilation, then the moisture that forms there has to go somewhere, otherwise, you'll have mold like never before. I can't answer if you need it or not, if the slab is dry and fine, then maybe you don't need it.