ᐅ Exterior Wall: Calcium Silicate Blocks with Polystyrene Insulation vs. Hollow Clay Bricks
Created on: 25 Feb 2022 16:31
N
NilsHolgersson
Hello everyone,
I have a few questions regarding materials for exterior masonry walls.
The plan is for a single-family house, about 150 sqm (1,615 sq ft), two floors plus a basement, hip roof (urban villa style), not KfW-certified—so according to the Energy Saving Ordinance (technically like "KfW60"), air-to-water heat pump, underfloor heating, central controlled ventilation with heat recovery. The area is quiet.
According to the construction specification, the walls are to be built with 24 cm (9.5 inches) sand-lime brick plus 17 cm (7 inches) external insulation with EPS (expanded polystyrene) and an ETICS (external thermal insulation composite system). An alternative is perforated clay brick 36.5 cm (14.4 inches) without cavity insulation—but with an additional cost of about 10,000 euros for the whole house.
I’m not particularly eco-conscious 🙂 but here are my thoughts:
- I have read that EPS means the external insulation needs to be replaced after 20–30 years—is that true?
- Birds and small animals like to use polystyrene as nesting material, causing holes and heat loss.
The option with the perforated clay brick is offered without filling (according to the consultant, at a wall thickness of 36.5 cm (14.4 inches) it is not necessary).
- Is it really sufficient without cavity insulation?
- What are the experiences with moisture and mold inside the wall when the brick is unfilled?
- If filling/insulation is recommended after all, which is best: mineral wool, “small stones”?
And in the end: which of the two options would you recommend?
Many thanks for your opinions 🙂
Kind regards
NilsHolgersson
I have a few questions regarding materials for exterior masonry walls.
The plan is for a single-family house, about 150 sqm (1,615 sq ft), two floors plus a basement, hip roof (urban villa style), not KfW-certified—so according to the Energy Saving Ordinance (technically like "KfW60"), air-to-water heat pump, underfloor heating, central controlled ventilation with heat recovery. The area is quiet.
According to the construction specification, the walls are to be built with 24 cm (9.5 inches) sand-lime brick plus 17 cm (7 inches) external insulation with EPS (expanded polystyrene) and an ETICS (external thermal insulation composite system). An alternative is perforated clay brick 36.5 cm (14.4 inches) without cavity insulation—but with an additional cost of about 10,000 euros for the whole house.
I’m not particularly eco-conscious 🙂 but here are my thoughts:
- I have read that EPS means the external insulation needs to be replaced after 20–30 years—is that true?
- Birds and small animals like to use polystyrene as nesting material, causing holes and heat loss.
The option with the perforated clay brick is offered without filling (according to the consultant, at a wall thickness of 36.5 cm (14.4 inches) it is not necessary).
- Is it really sufficient without cavity insulation?
- What are the experiences with moisture and mold inside the wall when the brick is unfilled?
- If filling/insulation is recommended after all, which is best: mineral wool, “small stones”?
And in the end: which of the two options would you recommend?
Many thanks for your opinions 🙂
Kind regards
NilsHolgersson
hanse987 schrieb:
The thermal insulation is fine. Hollow bricks without filling are not great for soundproofing. Using 36cm (14 inches) hollow clay bricks without insulation is certainly possible, but
hanse987 schrieb:
The thermal insulation is fine. Hollow bricks without filling are not great for soundproofing. However, a 36cm (14 inches) brick will never come close to the sound insulation and thermal performance of sand-lime brick plus 17cm (7 inches) of insulation. Not even close.
Is the general contractor or builder really offering that for the same price? If so, I would accept immediately.
Unfortunately, I don’t have current prices, but the cost of bricks per cubic meter was around €80 about 2.5 years ago, XPS foam was about €100.
By now, XPS is probably around €220-230 per m3.
NilsHolgersson schrieb:
According to the building specifications, the walls will be constructed using 24cm (9.5 inches) calcium silicate blocks plus external insulation of 17cm (7 inches) polystyrene with an external thermal insulation composite system (ETICS). Alternatively, 36.5cm (14.4 inches) hollow bricks without filling can be used. You can find my collected thoughts on the topic by searching for "11ant Steinemantra". To summarize simply: "choose the wall construction your builder is more experienced with." If they offer construction types A and B in a ratio of 60:40, you have the freedom to choose; but if the ratio is 90:10, then definitely forget option B. Building defects are caused many times more often by workmanship than by the materials themselves.
https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/
Similar topics