Solid wood house / partial self-labor, wall structure / differences

Good morning Friedrich,

Time: Right, I wanted to express that your concept is probably fine for you, but the majority of home builders won’t be able to handle it.

Yes, okay – the quintessence should actually not be the message of the DIY. The trigger was your statement to best not (re)build at all. In the case of an existing house, in my opinion, one no longer has to worry at least about the energy balance of the shell. If you already get into a moral conflict over every bit of cement, that would avoid quite a bit of conflict potential. That was the basic idea. Sorry if I conveyed that so misleadingly!

Money: When I read everything you do and assume that the majority of home builders cannot do this themselves and have to hire craftsmen, then I think it will get pretty expensive. That’s why new construction makes more sense.

Renovation will probably be more expensive than new construction in most cases. For that, in my very subjective view, you don’t get a ready-made house or one of a kind, size, and floor plan that you wouldn’t be able to afford with a new build today. If I take my “small villa” with 340 sqm of living space plus 60 sqm extension, I would probably have to pay millions for a new build. Nobody builds such a thing anymore today.
Whoever has the nerves and money to invest and wants to can also have everything done by companies. I don’t allow myself this questionable luxury because I can just afford to pay for my materials, of which I do not skimp on quality, and building has been a fixed part of my life for nearly 20 years. I am not afflicted by a stingy mentality.

Risks: Where do the risks come from, from “being stingy is cool”? As long as people believe that building has to be mainly cheap, risks are wide open. It starts with wanting to save on a proper architect and engineer, goes through the craftsmen to the materials up to, of course, expensive fittings, etc.

Yes, you’re largely right there. But as always, statements cannot be generalized. There are also quite a few families ruined by construction companies who were not “stingy cool savers” but wanted to move into a new house.
Although some “stingy mentalities” appear here in the forum who want to save on the essentials. Whoever then falls on their face at least knows why.

Insulation: Not a word about it.

Yes: keyword lightweight expanded clay aggregate. I wrote about it regarding the floor slabs. But as explained above, the focus of my contribution should not have been to describe my current situation but rather the energy-related view of renovation versus new build. Unfortunately, it didn’t come across that way.

I am a convinced timber builder and we never insulate with products of the petroleum industry. We have excellent insulations from our own material if only “being stingy is cool” weren’t again an issue. Our insulation materials just cost a bit more. There are no uninsulated floor slabs at all and the houses are built tight, equipped with sensible heating systems, and the windows also have excellent values.

My point exactly – in new builds as well as renovations. Except for the difference in airtightness.

Energy consumption: That an old building consumes more just because of the higher ceilings I would call a fairy tale. Certainly, you are right, it’s not just about the walls but about a comprehensive insulation concept that also includes the airtightness of the building envelope. Highly insulated building envelopes consume significantly less energy; that is an indisputable fact. Maybe you should get a blower door test done at the end. I really hope for you there won’t be a nasty surprise. Maybe I misunderstood you there, I just haven’t read anything about insulation.

Not only because of the increased cubic meters, but also because of that. I had written that the increased energy consumption is also due to the fact that renovated old buildings can never be executed as tightly as new buildings.
Even calculated to the maximum reasonable extent, the trade association of mineral wool industry assumes only 25% possible heat loss through the facade. Windows and roof / floor slab already each account for 30%. In many solid old buildings, which have half-meter thick exterior walls with an air layer like mine, the 25% is probably overestimated. Now I have installed new insulated glass windows and replastered the window walls completely with 25-30 mm thick mineral insulating plaster (e.g., pumice additives, NO Styrofoam). That should suffice together with 25 cm of high perlite/clay screed as floor slab insulation as interior insulation. I am already aware that you use more heating energy in such an old house. By the way, I have been collecting and drying wood for years because I want to install fireplaces next.

Glue: Once again, chipboard no longer plays a role in structural construction. If such things are still available in hardware stores, it’s because many DIYers think: “I live in a house and there is Mr. Google, so I am a construction expert and besides that, everything is so cheap.” In structural construction, PU-bonded OSB boards are generally used, and floors (laminate and prefabricated parquet) usually have MDF boards as carriers. That doesn’t mean there isn’t anything else. FDH (sick house syndrome) is and has been brought into houses less by building materials but rather by furniture, floors and, you wouldn’t believe it, wool carpets. Not everything that comes from nature is ecological.

In my opinion, E1 should have been banned long ago because it represents decades-old knowledge that has since been disproven. The “stingy-is-cool hobby craftsmen” you so vividly describe shouldn’t even have the possibility to officially buy this stuff.
Why do you distinguish so carefully between OSB/chipboard and MDF? Regarding E1, the FDH limit values according to EN120 are set in one breath for both materials (0.1 ml/m³ (ppm) according to EN 717-1).
By the way: even the “Blue Angel” only states that the already far too high E1 norm is undershot by at least 50%. But even that is still considered hazardous to health by many institutes (I’ll spare you the list).

PU: I have to repeat myself. Modern wood products glued with PU (OSB, BSH, KVH, BSP) have no emissions from the PU glue. Of course, great care must be taken during processing in factories to protect employees. In the cured state, and that’s the only state you get as a customer, there are no measurable emissions and the measurement methods are highly developed.

Hm, then I really don’t know why, for example, the Environmental Institute Munich e.V. explicitly lists the “formaldehyde-free PU chipboard” you praised so highly as an indoor pollutant with carcinogenic substances. They must have been mistaken, the university…

Yes and greetings from P.

Greetings from M

The text after my greeting belongs under the link, sorry.

Thank you for the text. I had been looking for it but couldn’t find it anymore. I think in the past people have often praised modern building materials that later turned out to be toxic and dangerous. Sometimes you only really know that later. I prefer to rely on old, proven, and harmless materials. As a layperson, I wonder how people could build houses when all the modern stuff didn’t exist, especially ones that last for centuries and are not ready to break after 40 or 50 years. I don’t know. I have to make sure I finally make a decision and find a house affordable for us. Dreams don’t help if you can’t raise the necessary cash.

I will try to draw a floor plan. My dream house. Preferably a simple bungalow about 120 to 130sqm in size like a barn with a visible gable roof and large window surfaces and a covered terrace to the garden. But it must not look like a supermarket under any circumstances. I found a house at the moor on the internet that I really like from the outside.

Wall construction either only made of wood or insulated with natural materials (regardless of whether wood insulation, lava filling, hemp or cellulose), floor slab without Styrofoam (if not possible, I could live with it), interior walls in the sleeping area and pantry with clay, floors made of natural wood in the living area and natural stones in the wet area. Shower bathroom with level-access shower without tub and rain showerhead, shower bathroom and guest WC definitely with windows, sleeping area and shower enclosed and separated from the rest, windows and doors sealed with natural materials, at least Kfw 70, preferably 55 standard, as much technology as necessary and as little as possible, solar cells for hot water, chimney connection (stove later), environmentally friendly heating system, but no pellets. I would also prefer a wall radiant heating system. But I think that is not feasible if we want more than 110sqm of living space. And I still have to draw the floor plan again, because so far I always tried to draw the rooms within the 108sqm predetermined building volume. There is always a cozy corner missing for me.

That sounds quite good. I would suggest planning the entire building structure with 10 cm cross-laminated timber. That is sufficient for the walls and probably also for the roof panels. The ceilings will likely be 12 or 14 cm. The entire envelope equipped with double-beam girders, I estimate starting at 20 cm. On top of that, as wind and impact protection, a 20 mm wood fiberboard, counter batten/batten as support for the wooden facade and roof covering. For the facade, larch or Douglas fir left natural. The whole thing blown with cellulose insulation. Wooden windows which you simply screw onto the structure from the outside with a frame extension. Pre-install compressible tape. Of course, again chemistry in my opinion but justifiable. Here I think it is a compromise because it simply creates a secure sealing condition. For the window sills, I would recommend folded zinc sheet metal. The next compromise because it is durable and, due to manufacturing in one piece, safe against lateral penetrating water. By the way, the entire roof covering also represents a compromise. Unfortunately, except for reed, I know no truly ecological material and that is probably not an option. You should consider in the basic construction whether you do without a floor slab entirely. If I were to build something like this personally (and this applies only to me personally, not even my wife would go along with it), only a raised house would be an option. That means point foundations and a cross-laminated timber ceiling on top. Far enough above the ground so that air can circulate and the ground is gravelled. Perhaps ensure that a larch layer is built downward. Then, in planning, lay the supply lines for utilities preferably in the middle of the house and make sure you manage with a central technical area (drainage). By the way, with cross-laminated timber, pay attention to airtight material, meaning either 5-ply or glued narrow joints. If you have planned the envelope as airtight and highly insulating as possible and your floor plan is as open as possible, you should be able to heat with your basic stove (maybe soapstone?????). Additional heating for the bathrooms?!?!?! Everything of course must be calculated according to building physics and then offered to a proper timber builder. For the interior finishing, plan according to desire, mood and budget, perhaps even as self-work (your craftsman family). You can certainly then do without the gas connection, ventilation systems, and the like here. Inside, I would do most of the visible wood, meaning no further cladding of the surfaces. Where you want plaster, use clay building boards, which you can apply yourself. It would be a shame if you don't manage with your budget. Regards Friedrich.

I don't understand everything yet. I thought plywood is glued with PUR adhesive like, for example, KVH.

My wish from the beginning was point foundations without a base slab. I gave that up because we apparently can't afford it. My husband has no problem with that either. Actually, I also thought at the beginning that our budget is not unrealistic. There are people who buy prefabricated houses including land for under 300,000 EUR. But those are stone houses; apparently, ecological wooden houses without PUR adhesive are considerably more expensive.

But first, I will draw our floor plan over the weekend without letting myself be restricted by the given grid and will get back to you.