New floor joists in the log cabin, how would you have done it? Stuck...
Go team! I'm not an expert, but there seems to be a consensus to never use pressure-treated wood indoors, not even in the garage or similar spaces. I found a random page from Finland, read at the bottom: http://www.naturochmiljo.fi/vi_publ...31-23972-alternativ-till-giftiga-brader-finns
Yes, most say you should avoid treated wood, but it seems common to screw a treated board under the beam like 22x95, so then you wonder if it's necessary or completely unnecessary? Now, I can't screw the board from underneath, so it will still be untreated wood at the bottom, so maybe I might as well screw "regular wood on the side and lay the boards on?nikasp said:
What is the appropriate dimension for the supports for the boards? Do you need to place supports on all four sides of the sections, or are the long sides sufficient?
It is simply a matter of stating that the only way to prevent this beautiful structure from suffering from moisture and mold problems on the underside of the construction is to limit the amount of insulation in the crawl space to about 10 cm, so that the heat leakage downward keeps the temperature at a reasonable level. A suitable dimension for crawl space boards is 21x34 mm. Pressure-treated wood does not help against mold. However, there is borate-treated plywood that resists better.
A question regarding the studded interior wall: How were you planning to support the floor along the interior wall, where it runs parallel to (on top of) the floor joist? I would have placed two parallel joists, one on each side of the wall, and mounted noggings between these joists. Then I would have studded up the interior wall on the noggings. This way, the floor gets proper support right up to the wall.
Member
· Västernorrland
· 12 030 posts
now, you can't really say that it IS like that? All buildings are different and the ground can be such that you never get any problems regardless of how well you build the floor.justusandersson said:
Yo! It's the temperature differences between indoors and the ground that control the whole thing. It's about basic physics. No crawl spaces work today with normal insulation standards.
Can't find any 21x34, the closest I find is Batten 25x36mm, would batten work? Is it preferable to screw or nail the boards into these? What type?justusandersson said:
Regarding the insulation, since I'm attaching the subfloor boards on the side of the beams, I can adjust any thickness/height of the insulation, should it aim for the insulation to be flush with the chipboards and the cavity to be completely filled without air gaps?
You write 10cm insulation, theoretically, I can fit 19cm, how much colder will the inner floors be if one chooses 10cm?
Is there any golden rule about when the insulation is too thin and "too much" heat leaks out downwards making it difficult/expensive to heat the room?
If you install underfloor heating, is there a greater chance it works with thicker insulation?
That we don't have the house constantly heated to 20-21c, does it matter in this context?
Yes, it didn't turn out completely optimal, but if you don't have the drawing 100% clear from the beginning, sometimes surprises arise when you realize a wall can't stand where you initially thought.. ..BlueX said:
The plan now is to add blocking afterwards to reduce the length and attach a smaller stud 45x45 or 95x45 between the blocking parallel to the interior wall to screw the chipboard into.Yes, it's a bit difficult on the internet to filter out what is idiotic, risky, inappropriate, acceptable, good, idiot-proof, etc...Stefan1972 said:
You don't want to do something that you know will go wrong, yet in a renovation, you can't make everything 100% idiot-proof since it is often both technically and economically impossible. So, it becomes a sort of compromise, which in some cases works well and in other cases doesn't.
25x36 works well. Screw towards the sides of the beams. The short sides don't need any strips. Particleboard is not an optimal material for the subfloor. Plywood is best. OSB is probably OK too. You simply lay the boards from above without fastening. Then you must lay asphalt felt type, AC 350, allowing it to go up the sides of the beams before installing insulation. I would let the subfloor sit as low as possible, but the other option probably works too. It is best to use cellulose fibers as insulation because it is more hygroscopic. I don't think the floors will feel cold. The increased heating need is mostly noticeable on the energy bill. An alternative I hadn't considered before could be to lay out ground boards (special mineral wool) directly on the ground if you can access it. Then you could insulate as usual. The charm but also the problem with "Bygga hus" is that it mixes amateurs with professionals. You have to think for yourself.
Part of the charm of starting to renovate old houses. Choose at least 95x45. 45x45 doesn't support much.Earplugged said:Yes, it didn't turn out completely optimal but when you don't have the blueprint 100% clear from the start, sometimes surprises occur when you realize a wall can't be where you initially thought.. ..
The plan now is to add blocking afterwards to reduce the length and attach a smaller stud 45x45 or 95x45 between the blocking parallel with the interior wall to screw the chipboard into.
I forgot to mention that there is a special "blindbottenboard." Similar to masonite but thicker. Pre-cut to fit between joists that are spaced at c/c 600 mm. Probably available in lengths of 2400 mm. I don't understand the suggestion to use 95x45. The "blindbotten" should only support itself and the insulation.
Thanks for all the input!justusandersson said:
Regarding 95x45mm, there are different things being discussed and easily mixed up in the same thread...
95x45 was to fasten the floor chipboard where there was no floor joist to screw/glue into; I placed an inner wall directly on the joist, which would make the floor chipboard hang in the air along the wall.
When I talked about the insulation against the chipboard, I meant that the insulation lies on a blindbottenboard (the hardboard variant), and the question is whether you should move up the blindbotten so that the insulation completely fills the space between the blindbotten and the floor chipboard if you choose smaller insulation? If you move up the blindbotten, most of the floor joist ends up on the cold side and vice versa... good or bad? If you don't move up the blindbotten, sound and resonances should spread more easily since there's an empty space under the floor chipboard, right?
The acoustic aspect is difficult to assess. Many soundproofing constructions are based on a combination of cavities and insulation. If you are not going to play live rock music, I think you can disregard this. When you want to dampen footstep noise between floors, it's important to use the heaviest insulating material possible. But that's not relevant here. I would put the subfloor as low down as possible, to get as much of the timber as possible on the warm side.
He he, funnily enough, live rock music will be played.... the drums and electric guitar are the main reasons the room is being furnished...justusandersson said:
now it's not a residential house so no one else will be disturbed, but if you can avoid unnecessary resonance sounds, it's good.