ᐅ Exterior Insulation: Building a House with Poroton T7 Clay Blocks and Mineral Wool

Hello!

We are planning to build our house using Poroton T7 MW blocks. Our question concerns the wall thickness. The ground floor will have a brick veneer. Since the brick will also add a certain thickness, we want to build the ground floor walls thinner than the upper floor walls and accommodate the brick in that area. The question is:
Is it better to have 36cm (14 inches) on the ground floor and 42cm (17 inches) on the upper floor, or 42cm (17 inches) on the ground floor and 49cm (19 inches) on the upper floor? Are there any other options for insulation in this case?

Many thanks to the experts here!

What exactly is the reason for this … let’s say somewhat unconventional wall construction? From a cost perspective, this is probably the most expensive option, without any chance of it ever paying off over time.

Good luck

K1300S

Does the term "unconventional" refer to the additional brick cladding or the general choice of the T7? This model was recommended to us, among others, by the architect. The brick cladding is, of course, purely an aesthetic feature, so no cost savings are expected ;-)

Yes, it’s about the combination of insulating bricks PLUS facing bricks (which I also find structurally interesting for the upper floor). The option of insulating bricks with thin brick slips seems more reasonable to me – it is also more cost-effective and likely causes fewer issues. In that case, you would probably use the same brick thickness upstairs and downstairs (36.5, 42, 49 cm (14.4, 16.5, 19.3 inches)). Are you set on building a passive house or something similar?

Good luck

K1300S

Since we are building with a gas heating system and solar thermal, it probably won't reach passive house standards (more likely around a 55 standard, maybe closer to 40). However, it would be nice to later achieve passive house performance by adding a heat pump and photovoltaic system.

Having a uniform wall thickness would of course be ideal. However, we are concerned that the brickwork might become too thick and provide too much surface area exposed to weathering. The thin bricks are said not to be very durable and somewhat fragile? But I am not an expert myself.

Hello,

Serage schrieb:
.... It would be nice to achieve a passive house standard later by adding a heat pump/photovoltaic system....

Your wishes and expectations are understandable, but this will most likely fail badly!

Best regards