ᐅ Timber House – Interior Walls Made of Masonry?

Hello,

I am currently planning a single-family house (bungalow, about 180 sqm (1,940 sq ft)) to be built using solid wood construction. For wooden houses, especially those insulated to KfW standards, it is said that they are easy to heat up quickly. However, due to the lack of thermal mass, I was told that they also cool down quite fast again. To compensate for this, a question came up in a recent discussion about what it would be like to build the interior walls out of calcium silicate blocks or bricks.

We didn’t get very far with this question. So I’m asking here:

Does it make sense to build the exterior shell in solid wood and one or more interior walls in masonry?

Maybe someone can provide some insight.

Thanks in advance.

Best regards

Why?
This idea is completely new to me.
A wooden house has dimensions, of course. You probably also have insulation in your house.
Cooling down takes a long time due to the airtight envelope and insulation. Heating up when it actually gets cold, for example, due to heating or ventilation failure, takes time. This has nothing to do with the house being made of wood, but rather with the fact that the supply temperatures are lower.

tadeus321 schrieb:

I am currently planning a single-family house (bungalow, about 180sqm (1,940 sq ft)) to be built using solid wood construction. For wooden houses, especially those with KfW insulation standards, I have heard that they are supposed to be easy to heat quickly. However, I was told that due to the lack of mass, they also cool down quite fast again. [...]

Does it make sense to build the exterior envelope of a house with solid wood and one or more interior walls made of stone?

Your idea is feasible with some effort and especially with a freely spanning roof structure. It’s not so far-fetched that it would be laughable. However, it is still somewhat naive, so I advise you to reconsider other fixed assumptions you may have and preferably discuss them here as well. Furthermore, you have been misinformed: solid wood houses in fact have a very high thermal transit time—actually longer than the standard allows—making it more difficult for manufacturers to determine the U-value in laboratory testing compared to other wall constructions.

So please consider this an open invitation to a broader discussion with us: my advice would be to start an introductory thread and enhance its first post by filling out the questionnaire at the beginning of the floor plan section. Then we can work our way toward your house. A 180sqm (1,940 sq ft) bungalow usually only fits well for a childless couple living off private means (otherwise, it tends to raise assumptions of further naive motives like “saving on stairs,” “single-level living is more age-friendly,” or similar). Do you even have a specific plot of land yet? Please answer this preferably in the new, linked thread.

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Basically, I can follow your line of thought. However, without being able to support it with exact figures, I assume it won’t be cost-effective. When it gets cold in autumn, you might be able to start heating about 2 weeks later (just my assumption). On the other hand, you will face additional effort during the planning and construction phases due to the different building methods. Also, you will probably need two different contractors, both of whom would normally prefer to build an entire house themselves.

What led you to choose a solid wood house? If you are convinced by the benefits of wood as a building material (ecological aspects, etc.), then you shouldn’t install masonry walls just to save a few dollars on heating costs.

In 2015, we were looking for a passive house builder. The ones we contacted who build using solid masonry declined, saying massive timber was not an option. I’m not sure if this was due to the material itself or the type of clients they usually work with.

If massive timber cools down faster, it would be more challenging. Actually, we had always heard the opposite.

Massive timber is said to have longer cooling times than solid masonry.

Thoma Bau Austria provides an overview of the cooling times. Are those accurate?

I would choose one building material, as mixing them causes problems. I would choose massive timber again every time.

We had exactly this issue, but only regarding the party wall between our two semi-detached houses.

In this case, however, the builder of the solid wood house simply has practical objections. The solid wood house is prefabricated in elements no larger than 9 x 3 meters (30 x 10 feet). When the trucks arrive with the house, the shell is completed including the roof within 3–4 days. It would not be possible to build our party wall with masonry, as it would have to stand free and straight up to 9 meters (30 feet) high. Building the ground floor walls first, then installing the house and waiting for the bricklayers afterwards would also not be practical.

If your interior walls on the ground floor are load-bearing, you will face exactly this problem.

A modern solid wood house, if constructed with a controlled ventilation system, only cools down “quickly” in winter when windows and doors are open. However, I do not yet have evidence for this assumption. I might be able to provide proof in about a year.

If there is still a “small” difference between masonry and solid wood interiors, I advise you to accept it.