I have made an addition to the cottage with a base of lecablock and crawl space. The floor structure consists of 220 mm joists. How much insulation should be used? Should a moisture barrier be applied, and where? I originally considered lin insulation but the price is discouraging 
As for the self-supporting tongue and groove wooden floor. Instructions are given to lay it at 20 degrees room temperature. This makes it problematic to lay it in the still uninsulated room during the winter season! Isn't it enough to store the wooden floor in a heated room shortly before laying? Then the floor will reach the moisture content that will eventually occur in the finished room. The floor will otherwise be screwed.
Thanks in advance for any tips!
Eric
As for the self-supporting tongue and groove wooden floor. Instructions are given to lay it at 20 degrees room temperature. This makes it problematic to lay it in the still uninsulated room during the winter season! Isn't it enough to store the wooden floor in a heated room shortly before laying? Then the floor will reach the moisture content that will eventually occur in the finished room. The floor will otherwise be screwed.
Thanks in advance for any tips!
Eric
Hello, regardless of what insulation you have, the joists should be fully insulated, cellulose works great, available as boards and loose fill, or make an old-fashioned subfloor and insulate with sawdust, very cost-effective I think. I don't have a definite answer on the floor, but I think if it's a dried-down floor that is plastic-wrapped, it should work to have it in a warm room for a while. If it's a regular floor from a cold storage, it probably needs to lay for quite a long time, in the past, they used to lay the floor in the room as usual without nailing it, after about 1 year it was disassembled, put together, and nailed, probably not done anymore.
There seem to be very divided opinions about plastic in flooring. The most important thing is that you get it completely airtight, though.
I would fill with stone or mineral wool insulation so it stays warm underfoot.
Spontaneously, it feels silly to have the wood in another room. Even if the planks themselves have the right temperature, the joists you're screwing into will have the wrong temperature, so there’s always a risk they might move a bit.
I would fill with stone or mineral wool insulation so it stays warm underfoot.
Spontaneously, it feels silly to have the wood in another room. Even if the planks themselves have the right temperature, the joists you're screwing into will have the wrong temperature, so there’s always a risk they might move a bit.
I would probably advise you to place the wood in the room where it will be laid. You should be able to use heating with, for example, a construction fan. I also don't know how good it is to lay a warm floor in a cold space. I consider it to be a recipe for problems.
Thank you for all the answers! I hadn't considered cellulose insulation at all. I also hadn't thought about the movement of the studs. Probably not easy to predict floor movements. I have no problem with gaps forming periodically. As long as it doesn't warp. Therefore, perhaps one should avoid a too dry floor during installation...
Wood primarily moves perpendicular to the grain, so I wouldn't be too worried about laying it on joists that aren't super dry. It might be that the floor could sink a millimeter when the joists dry. I would try to keep the floor as dry as possible before installation, if it's already dry. That means not letting it sit for a long time in an uninsulated room. However, there is a risk of installing a really dry floor in a damp room as it can swell so much that it pulls out of the screw heads. A proper expansion gap under the baseboards is very important, as it can otherwise push out the walls...
Hello again, now that a lot of good points have been made, I thought I'd throw in another one. I don't know if it's common, but we always put an underlay on the floor beam. I think some flooring manufacturers have something like that, it works with strips of lumpapp, for example. I believe it's to eliminate floor creaks.
We also used jo lumppapp when we installed a rift-sawn floor last winter. It still wasn't completely squeak-free, but that doesn't bother us much. I guess completely silent is hard to achieve with wide boards that warp. I've also noticed it squeaks a bit more at a plank that was twisted and stubborn, which we had to fight to get in place. Not too surprising, really.
It's also worth noting that there is quite a significant difference in humidity indoors between summer and winter. For those who really want to minimize the risk of the floor drying out, it should be left indoors for a couple of months during the winter and installed when it's the driest, say in February. Just leave room for expansion...
It's also worth noting that there is quite a significant difference in humidity indoors between summer and winter. For those who really want to minimize the risk of the floor drying out, it should be left indoors for a couple of months during the winter and installed when it's the driest, say in February. Just leave room for expansion...
Well, the whole issue with a wooden floor must be that when it is laid, it should have the average moisture content of the wood when it is in place. What this is can only be guessed. The floor will be in a cottage, which will periodically have varying indoor temperatures depending on when it is used. When I study my wooden floors in my permanent house, I see that the wooden floor in my uninsulated sunroom swells in winter and shrinks in summer. The wooden floor in the living room behaves the opposite, naturally since the house is heated in winter. I think I'll lay the floor next summer, give it a good expansion allowance against the walls, and keep my fingers crossed.....