When people talk about a CLT house, the conversation is usually about the structure, the build time and the energy performance. Those who already live in one, however, most often highlight something quite different: what it feels like to be inside. That is not just atmosphere — there are tangible physical reasons behind it.
The wood that "breathes" — what does that really mean?
The phrase "breathing wall" is misleading: the envelope of a well-built house is airtight, and air does not pass through it. What the phrase really refers to is the moisture-buffering effect. The surface of solid timber can absorb moisture when there is excess humidity and release it in drier periods — smoothing out swings in indoor humidity.
This effect only works if the CLT surface is exposed or finished with a vapour-open coating. Behind a fully sealed, thick lining the timber cannot play this role — so the design of the interior surfaces is a decision to be made at the design stage.
Warm surfaces, an even sense of comfort
Thermal comfort is determined not only by the air temperature but also by the temperature of the surfaces around us. Because of timber's low thermal conductivity, the inner face of a CLT wall feels warmer — both to the touch and by radiation — than a cold, hard surface at the same temperature. In practice this means the same level of comfort can often be achieved with a slightly lower air temperature.
Air quality: the other side of airtightness
In a modern, airtight building the natural "leakage ventilation" disappears — good for energy, but it means fresh air has to be provided deliberately. The most comfortable way to do so is mechanical ventilation with heat recovery, which exchanges the air continuously while recovering most of the heat from the outgoing air.
- No need to open windows regularly because of CO₂ levels and humidity.
- Incoming air can be filtered — which matters a lot in pollen season.
- No condensation in cold corners, so the risk of mould is minimal.
The choice of finishes, adhesives and surface treatments matters just as much: with low-emission materials, indoor air quality stays good from day one.
Acoustics — the often-forgotten factor
Solid timber absorbs higher-frequency noise well, so rooms typically sound "softer" and less echoey. Impact sound and the sound insulation of floors, on the other hand, are a design task: a floating floor build-up on the CLT slab and resilient separations make sure that not every footstep carries downstairs. In an apartment building such as our Balatonalmádi project, this is one of the most important details.
What is worth deciding at the design stage
- Where should the timber stay exposed, and where should it be lined?
- Which ventilation system suits the floor plan and the way the house is used?
- Which floor build-up delivers the sound insulation you want?
- How will large glazed areas be protected from overheating in summer?
CLT building technology offers plenty of options on all of these — but only if we think about them together from the very first design version. If you are curious what this looks like in practice, take a look at our CLT family house in Fót.
