It would be interesting if those of you who build with alternative building materials/methods could share. Things that are not normally sold at a hardware store. Things that might require a bit more work but are often cheap or free.
Can't you tell us a bit about what you have built or plan to build?evalouise said:
For me, it's about applying clay plaster to a timber floor and putting up a rift-sawn ceiling that I will plane next week.
Here are some good courses on alternative building. One is about bathrooms with clay-plastered timber walls.
https://butiken.sormlandsmuseum.se/kurser/
I usually build something with alternative and completely free building materials almost every winter. Unfortunately, the durability is usually terrible, at most a couple of months, and then there's not even waste left. However, I've heard through the grapevine that it works slightly better in the northern part of the country.
Hi, This week I've been stuck in the bathroom and am wavering with the clay. I could trust the clay on the ceiling, together with a vapor barrier, träullit, and 15 cm Hunton insulation but know too little about silicates and tadelakt to test it on walls in a shower room. Unfortunately, it will probably be "traditional" with wet room boards and a waterproofing layer or an ugly shower cabin.Bjor said:
Is that a log house you have there? Do you lay wooden floors on top of the clay then? I would like to have wooden floors in my concrete house, I wonder if it would work to do a 2 cm clay layer on the floor and a parquet on top of that? Yes instead of plastic or felt paper? I have so many questions but where on earth are the answers? Hard to find. Wedge-sawn sounds advanced, isn't it hard to get and fit?
I haven't gotten as far as the bathroom yet, but clay-plastered walls will definitely be there, how to protect the walls I don't know quite yet. But maybe it will be a shower cabin built with brick and tiles that can handle a lot of moisture. It will be in the extension that will be built with brick blocks. A sufficiently thick layer in the ceiling should work well, because then it can buffer a lot of moisture. In my bedroom, I have a 10 cm thick clay ceiling built with woven branches and then 30-35 cm of hemp on top of that.
Yes, it's an old soldier's cottage made of timber. I have hemp and flax insulation on top of the clay, then the floor on joists on that.
It might be safer with a solid wood floor that can handle a little moisture, because then it should work well with having a layer of clay and then the floor.
It's just a matter of laying every other floorboard with thin and then wide sides and measuring sometimes so it doesn't go completely wrong. But it's not difficult and it goes fast to lay because they are so wide.
I'm using Hunton wood fiber insulation; it will probably work on top of the bathroom. I'm thinking of making a ceiling with tongue and groove paneling, clay-plastering about 2 cm on the top side, then screwing it up, and then laying 20 cm of Hunton insulation on top. But I'll have to install ventilation from the shower too, that's probably a must.
I'm still unsure about the wooden floor on the concrete (in the living room), but real planks are probably better, yes, than parquet. It's easy to lose confidence when everyone you talk to says that you MUST have plastic on the concrete before laying a wooden floor. I wonder how thick the clay layer needs to be under the planks to handle the moisture that might form in a 10 cm thick concrete floor with 20 cm of foam underneath, 10 cm of gravel, and a geotextile under that.
You don't have to have plastic on the concrete at all. Clay on top of the concrete doesn't change anything. It doesn't replace the function of the plastic, nor does it reduce moisture load. So it's completely unnecessary in your case, (on a concrete floor that is insulated and capillary-protected according to today's standards). Possibly, it may reduce the risk of mold if you happen to "water" the floor so there is free water between the concrete and wood, but that's speculation on my part. Possibly, flooring with a raised floor may have the same effect.
No plastic/moisture barrier imposes requirements on the flooring you install. It must be moisture-open. That is, basically untreated wood => soap/scrub floor. Modern glued floors are generally sensitive to moisture and are sealed due to both the glue layer and usually being varnished.
It's also probably appropriate not to install any flooring until the concrete has completely dried out and has reached temperature equilibrium between the indoor climate and the local ground climate.
No plastic/moisture barrier imposes requirements on the flooring you install. It must be moisture-open. That is, basically untreated wood => soap/scrub floor. Modern glued floors are generally sensitive to moisture and are sealed due to both the glue layer and usually being varnished.
It's also probably appropriate not to install any flooring until the concrete has completely dried out and has reached temperature equilibrium between the indoor climate and the local ground climate.
Anyway, I was told by the concrete company last week that it takes 25 years for a 10 cm thick concrete floor to completely dry out! Wow. Well, I have heating in the house, so I'm thinking that clay under the floorboards would absorb moisture both from outside and inside so that it becomes some sort of leveling, it's not exactly water puddles but ordinary moisture. And if there is no plastic anywhere in the house, then there shouldn't be mold anywhere, right? Still hesitating, working on the walls in the meantime...Oldboy said:
It's more theoretical, albeit interesting. For practical use, it's moisture content that's usually discussed. I don't know the exact limits, other than I think floor installation on newly poured slabs starts a bit too early. What would be interesting to know is the drying rate/moisture content over, say, the first 5-10 years. Then I assume there are studies on the relationship between moisture content vs. risk of mold and/or sick building syndrome and different floor coverings? Anyway, I imagine that after about a year with heat, the concrete is dry enough to install organic materials without excessive risk of mold (with a bit of margin)?
Unfortunately, plastic itself doesn't have much to do with mold. When used correctly, plastic protects against mold, but when used incorrectly, it can contribute to mold formation. Building a house without plastic requires extensive moisture knowledge and material knowledge for it to succeed.
The little moisture that will come from the concrete won't be a problem after 1 to 2 years. The clay evens out the moisture that comes from the concrete. A scrubbed floor can handle a lot of water, because there are almost puddles on the floor when I scrub it. It's the same when applying the clay, then I spray the walls/subfloor with water. A scrubbed floor can be a bit sensitive and can easily get marks on it. But that's one of the things that makes it more beautiful. Otherwise, you can paint it with linseed oil paint, in nice patterns. Read the book Painted Floors. Don’t worry about moisture in the floor and don’t use plastic. The clay will ensure that the floor maintains a low moisture level.
I would like to avoid plastic on the concrete now that I have had such a hassle with träullit and clay on the walls. and with all these "building experts" who are appalled by my beautiful clay!
But how thick should the clay be on top of 10 cm concrete (insulated) under a wooden floor that is about 26 mm? Should I lay the wooden floor directly on top of the clay then? or also use battens? I would prefer not to build up the floor more than necessary.Clay-plastered gables on the upper floor, it's so beautiful. However, this particular wall will have studs and be clad with Hunton insulation 14 cm, so I've used the clay instead of windproof paper kind of. I think I'll leave a small gap between the clay and Hunton, but I'm not sure if it's really necessary? I thought I could cut narrow strips of Hunton Windtight and press them into the clay. What do you think, Bjor? Should there be a small gap?