ᐅ Building permit application submitted / unresolved technical details / looking forward to suggestions

Hello everyone, our planner has now submitted the building permit application and asked us to consider a few things (on one hand, they want to start with the structural calculations, and on the other, to compile the documents for the tender).

17.5 cm (7 inches) sand-lime brick or aerated concrete: so far, we preferred sand-lime brick because of its thermal mass. We were told the cost is roughly similar. Aerated concrete offers about 25% better U-value (in our wall construction). Sand-lime brick, however, provides better thermal mass and sound insulation (though the latter is less important). Interior walls will be built with sand-lime brick. Can anyone strongly recommend one over the other? (cavity wall with insulation and facing brick)

Recessed spotlights or regular lamps: this might also be relevant for the structural load. I did a rough calculation – if we have to count €60 (euros) per spot, that could add up considerably. Some say spots are not ideal from a lighting perspective either. I’m leaning against them, my wife is in favor. Is this just a trend, or is it truly better than regular fixtures?

Tiles or other floor coverings: we have mostly tiled the ground floor. Now the question is what to choose for the upper floor – I would also lean towards tiles here. We had briefly considered cork – does anyone have experience with that?

Ventilation: it’s almost certain we will have a decentralized ventilation system with heat recovery—most likely cross-flow (no inverter - I know the pros and cons, but we would probably never feel comfortable with a central system). Does anyone have specific models to recommend or advise against based on whether they can sleep well with them or not? We have already visited five houses with central ventilation systems to “listen” and talk to the owners. Three of them have the system on the lowest setting or turned off because it bothers them (which kind of defeats the purpose). Am I allowed to mention companies here? I have read something about Blue Martin – they are expensive and supposedly very good – but it’s always hard for a layperson to tell if it’s just marketing.

Ground-source heat pump: is deep drilling better or are horizontal/spiral collectors preferable? Is it possible to cool with horizontal/spiral systems in summer as well?

Additional cost for engobed roof tiles: we need to decide on roof tiles, but the building supplier wouldn’t give us price details (they said prices would be sent directly to the builder). Can anyone roughly estimate the extra cost for engobed matte clay tiles compared to non-engobed matte clay tiles? Is it worth it or more about appearances during the first year?

Thanks for your opinions and best regards.

Regarding the engobed roof tiles, which are certainly more expensive than standard clay tiles, I would recommend investing in them. It usually costs just around 2,000 to 3,000 euros depending on the roof area. But it’s worth it when you see houses where the tiles turn completely green after 10 years. It also depends on factors like the nearby trees, but at least engobed tiles are less prone to this. My clear favorite is the glazed tile, but unfortunately, it is not yet permitted in our building area, as these tend to resist greening even more.

Now ask yourself whether you can accept how the tiles might look over time or if their appearance is already important to you.

Okay, that helps already. I thought that clay bricks generally don’t turn green that quickly.

My father-in-law works for the reputable brick manufacturer Meyer Holsen and therefore has experience with bricks. The engobe is a protective coating. His house and the neighbor’s house were built at the same time, but his bricks still look like new, while the neighbor’s already show signs of initial algae growth. This effect is even more pronounced with concrete roof tiles, where you can already speak of a greened roof.

Wall construction:
If you choose sand-lime brick for the interior walls, then you should also use it for the exterior walls...

Spotlights:
This is a matter of personal taste and budget. I would probably use spotlights in bathrooms and corridors, but not in living or bedrooms... Spotlights tend to give the room the feel of a medical waiting room...

Flooring:
This is also a matter of personal preference... I tend to prefer hardwood flooring.

Ventilation:
You mentioned you visited five houses with central ventilation systems, but have you been in any with decentralized systems? These are usually not quieter, sometimes even louder. Central systems are generally designed and calculated properly, meaning they still circulate enough air even at the lowest setting, it just takes a bit longer. Anyone who turns off the system because it annoys them either could have saved their money or the system was incorrectly designed or configured.

Heating:
You need to consider the overall design concept of the house; no general statement can be made here. The cooling effect in summer is minimal.

As for roof tiles, everything that needed to be said has already been covered.

Sorry, I made a typo: we visited houses with decentralized systems and they were noisy. Central systems aren’t audible, as we know. But we don’t necessarily want that (not rationally explainable).
Thanks for the input. So you would also use calcium silicate brick on the outside, despite the worse U-value (0.15 vs. 0.2)?