ᐅ Masonry Considerations => Summer Heat Protection

Hello everyone,

we are currently planning our house, and our developer is offering us 40 cm (16 inches) Ytong for the exterior walls. Some time ago, I spoke with an independent building expert because I was looking for the right type of block in terms of

- sound insulation between rooms
- summer heat protection
- winter thermal insulation

He said that the only material that really protects longest against the sun is sand-lime brick with an external thermal insulation composite system (ETICS) (for example, 17.5 cm (7 inches) sand-lime brick with 16 cm (6 inches) ETICS, possibly in other versions or as a natural product). According to him, this is the only way to keep the heat out in summer, retain heat inside in winter, and also provide sound insulation. For sound insulation, I could also use Ytong on the outside and sand-lime brick on the interior walls, but this requires careful workmanship (groove cutting) to prevent cracks in the walls.

From the interior perspective, he said that sand-lime brick retains the heat from a stove or similar sources better than Ytong.

So now I’m stuck... I’ve really done some research... but I’m confused again :-(

Can anyone help? To what extent is choosing sand-lime brick maybe considered "old-fashioned or cheap"? Or is Ytong with sand-lime brick interior walls the optimal solution?

Thanks in advance... please have mercy on a building beginner ;-)

Best regards,
Markus

Sand-lime brick and aerated concrete are almost the same price—and outdated? You can no longer build monolithic walls with sand-lime brick, of course—but you get slim walls both inside and outside, have sound insulation (which usually fails anyway at doors and windows), and of course also summer heat protection.

However, once the heat is inside the house, it tends to stay there as well—which can sometimes be uncomfortable.

We had our entire house built with sand-lime brick, except for the basement exterior walls.

@ Sebastian, is it made of sand-lime brick with external thermal insulation composite system (ETICS) or is there also a version without ETICS? What KfW efficiency standard can be achieved with it?

No plastic on the wall (okay, on the two bay windows with plaster it does go on 😀), but mineral wool instead – we have 14cm (5.5 inches) insulation and easily achieve KfW 55 standards, although we only applied for KfW 70.

Well, apart from the bay windows 😉

Ok, got it.. so far, I had only considered using solid blocks like Ytong or Poroton to achieve the KfW 70/55 standard for the exterior walls.

Ytongg is a manufacturer—primarily of aerated concrete that is not filled 😉.

KfW values always result from the overall interaction of various factors—not just the exterior wall, as is often the case here (currently, the wall construction is rather poor in terms of energy performance).