ᐅ Wall construction of a country house

@RFR That’s what I used to think as well. However, I’ve already noticed in my neighborhood that houses built with thin bricks and polystyrene insulation, with their main living areas (and windows) facing east, become very warm in summer. On the other hand, houses constructed with thicker bricks (all Poroton T12) without insulation, where the larger windows face south and west, stay noticeably cooler during summer. The same goes for our current prefabricated house (built in 2008, KfW 60 standard): it’s really cozy and warm in winter, but unfortunately also quite hot in summer.

We also had the chance to test different insulation materials when we were still looking for a builder: hemp and polystyrene were both exposed evenly to a heat lamp. After 2 minutes, the polystyrene was hot on the back side, while the hemp remained significantly cooler. The heavier the material, the better it protects against heat.

This is due to the better heat storage capacity of hemp or wood wool compared to polystyrene.

What about calcium silicate bricks plus external thermal insulation composite system (ETICS) / external wall insulation (EWI)?
The high mass certainly can’t be a disadvantage in summer...

(from outside to inside) 10.5 cm (4 inches) facing bricks, 2 cm (0.8 inches) air gap, 22 mm (0.9 inches) wood fiberboard (this material provides good heat protection, for example), 6x20 cm (2.4x8 inches) KVH (timber framework) insulated with 20 cm (8 inches) mineral wool insulation, 15 mm (0.6 inches) OSB as a vapor barrier layer, 6x8 cm (2.4x3.1 inches) KVH battens as an installation cavity insulated with 6 cm (2.4 inches) mineral wool insulation, 12 mm (0.5 inches) OSB and 12.5 mm (0.5 inches) drywall.
All dry, KfW 70 standard or better (depending on other components), clean interior finishing work especially by electricians and plumbers, easy and simple to install personal wiring such as LAN cables or speaker cables, much can be done by yourself particularly during interior finishing, the wood fiberboard is windproof.

Manu1976 schrieb:
Poroton is recyclable, Styrofoam is hazardous waste.

Styrofoam is also recyclable and therefore a valuable raw material.
Besides, you shouldn’t look any further. Every house contains “hazardous waste.”

One00 schrieb:
This is due to the better heat capacity of hemp or wood wool compared to Styrofoam.

What about sand-lime brick + ETICS?
The high mass certainly doesn’t hurt in summer...

In addition to the high thermal storage capacity, it also offers good structural properties and effective sound insulation.

Polystyrene can be fully recycled; however, there are some concerns. The flame retardant hexabromocyclododecane is very persistent, classified as highly toxic to aquatic environments with long-term effects, and is considered poisonous. Additionally, in external thermal insulation composite systems (ETICS), the render often contains pesticides and algicides, which can be washed out by weather exposure, causing the render to lose its protective function. From customer feedback, it is known that after around 8 years, black algae and similar growths start to develop on the render surface. It is also important to consider that the substances washed out may enter the garden (vegetable beds nearby?), or potentially be ingested by birds, cats, or dogs drinking from puddles, or enter the sewer system and subsequently the natural environment.

Hexabromocyclododecane is insoluble in water and forms a strong bond with the polystyrene that does not easily break down. This requires elevated temperatures. Therefore, EPS is not fireproof but fire-retardant. Alternatively, there is now EPS that does not contain hexabromocyclododecane, identifiable by the Blue Angel label. Regarding paint, it is of course also possible to choose paint without fungicides. Algae growth can occur not only on ETICS (external thermal insulation composite systems) facades but also on other types of rendered facades or, in some cases, on brick facades. Whether and how much algae develop on facades also depends on the location/shading and, above all, adjacent vegetation.