Hello everyone,
I will insulate my floor slab with straw and came across this thread.
Since it is not that old yet, I will revive it.
The straw will surely not just be "laid under the floor," but somehow processed or treated. Pressed, mixed with a binder or something?
if the straw bales are to be used as they come from the field, there needs to be an idea of how to fill the gaps that "remain." (as far as I know, "gaps" in insulation make the entire insulation significantly weaker)
... and these bales are not fire-retardant treated.
You can, for example, use a wooden frame construction like the one used for walls. Simply timber frame construction, or wooden planks. The straw bales are pressed in there so that you get a bulk density of about 100 kg/m³ of straw. There are no cavities left; you can’t even get your hand in.
The elements then need to be clad accordingly to meet fire protection requirements.
For exterior walls, clay plaster is typically used on the inside and lime plaster on the outside. On the outside, you can also clad with wood, then you can plaster underneath with clay.
Also possible for the roof, and especially regarding summer thermal insulation, it is supposedly very good. However, I have no personal experience with that yet.
A "straw house" is not far from here. I sometimes watched the construction and found it quite "sympathetic."
Straw "works" anyway (however, the walls were at least half a meter thick).
You can have the wooden frame made by a carpenter yourself, according to the engineer’s specifications. But there are already system providers producing prefabricated walls.
For example, Lorenzsysteme (Lorenz GmbH), they have 3 wall thicknesses in their range, the thickest is 34 cm and offers a U-value of 0.162 W/(m²*K) without plaster.
Greetings!
Sebastian
