ᐅ Experiences with Poroton S9 or T9 Blocks

Hello experts,

I’m new here and really excited to have found this site. We plan to build next year and are still in the planning phase. The following points are very important to me for the build.

- Solid construction with Poroton (36.5 cm (14.4 inches) exterior wall)
- Without ETICS (external thermal insulation composite system)
- KfW 70 standard
- Air-to-water heat pump
- Underfloor heating
- Triple-glazed windows

I want to build with Poroton, but I already have some doubts. I’ve read a lot about filled Poroton bricks like T7, T8, T9, and Unipor Coriso WS08. My question is whether I could also use an unfilled Poroton brick, such as Unipor WS09 or T9 plan bricks. I contacted Wienerberger to ask which bricks would be suitable. They said that the filled bricks are good, but if unfilled and without external insulation, then the T9 plan bricks (36.5 cm (14.4 inches)) would be recommended.

Is this suitable for a KfW 70 house, and does anyone here have experience with this? Alternatively, I would consider using the filled bricks, but I’m not sure about the practical experience with those, especially combined with perlite or mineral wool.

Thank you very much for your answers.

Regards,
jayden1977

Hello experts,

No suggestions or answers. I would really appreciate having some opinions. The views from the developer vary greatly.

Regards

Jayden

Why did you decide against aerated concrete? Are there important reasons for your choice of Poroton?

What do you think are the disadvantages of solid bricks?

Hello everyone,

I would not recommend aerated concrete because sound insulation is very important to me. I have a large family with many young nephews (6 boys), and I have two boys myself. Additionally, I plan to build near railway tracks (train station). My brother-in-law has built with Ytong, and apart from its excellent thermal conductivity and ease of installation, I wasn’t very impressed.

Thermally insulated clay blocks are also very good, but which ones? There are the T Series from Wienerberger, but I thought the webs are too far apart. If I want to screw in small screws, I would hit the insulation material—whether mineral wool or perlite—or I could use the Coriso blocks from Unipor, which I like a lot but they are quite expensive.

What has been your experience with thermally insulated clay blocks?

Thank you very much for your answers.

Best regards

Jayden

Hello,

I’m not a fan of highly insulated, filled bricks like T7, T8, or T9. These try to turn a "brick" with load-bearing functions into something it wasn’t meant for. These systems only work in theory.

The thin-walled brick material is brittle and prone to cracking. Many bricks break already during rough unloading of pallets on site. At highly stressed points, such as supports for lintels, damage often occurs during masonry work. This later becomes visible in the exterior plaster.

Working with the bricks in thin-bed mortar is also not without challenges. You’re supposed to have a continuous mortar layer without contamination from the perlite. The reality looks different.

The actual insulation, which is the perlite filling, constantly has thermal bridges because gaps are simply filled carelessly with mortar or plaster, or the filling falls out during cutting and the brick is still used. Every electrical outlet on the outer wall also reduces the U-value compared to an external thermal insulation composite system (ETICS / external wall insulation).

There are many other aspects, but that would go beyond the scope here. For monolithic construction, I find aerated concrete (e.g., Ytong) much more practical. For high energy efficiency demands without annoying thermal bridges, there is no way around full external insulation.

Regards,
Phillip