ᐅ Home Construction: Guidance for Making Decisions on the Details

Good morning, we actually hoped to be living in our own home by now, but unfortunately—or luckily—that didn’t work out. Now, freshly "separated" from our former general contractor (Hv.), we have handed the project over to an architect. But even here, decisions about building services and other technical aspects still need to be made.

That’s why I’m asking for your help here 🙂

I’m not sure if these questions belong better in the subforums, if so, sorry. Just let me know, and I’ll post them there.

General information about the house:

1. Single-family house with 2 full stories without a basement

2. Solid construction with T10 or T8 blocks without external thermal insulation composite system. The choice of the block type will be decided when the quotes come in, since it’s mainly a cost issue.

3. Gas condensing boiler combined with solar thermal system on the roof providing about 50% of the domestic hot water

4. Mechanical ventilation system with heat recovery

5. Approximately 170 square meters (about 1830 square feet) of living space with around 800 cubic meters (28,250 cubic feet) of enclosed volume

6. Open roof structure, meaning no attic space

Now to my questions:

1. Due to the roof pitch, “normal” roof tiles are not possible. The architect suggested roof panels, I believe fiber cement panels from Eternit or aluminum roof shingles from Prefa as options. I’d like to hear your opinions on this, both regarding durability and watertightness as well as noise levels—especially since the ceiling of the bedrooms is basically the roof. I imagine it could be quite loud during rain, but am I mistaken?

2. Which gas condensing boiler would you recommend in combination with a solar thermal system? Any preferred manufacturers?

3. Regarding mechanical ventilation with heat recovery, what experiences do you have? Which brands can you recommend? I’m particularly interested in the ease of cleaning in case of mold or germs—which often comes up in discussions—as well as the running and maintenance costs.

Thank you very much in advance!

Regarding point 1) there will still be insulation in between, about 25 - 35 cm (10 - 14 inches). So the ceiling of the room is by no means directly the underside of the roof. What is the roof pitch?

Yes, I understand that there is insulation, plasterboard, etc., between the actual roof and the ceiling.

Still, I’m asking about the noise level, for example, during rain.

The roof pitch is a bit complicated. It is a gable roof with a crosswise roof overhang.
I can’t say exactly, I would need to ask the architect again for details. In any case, it should be like this, so interlocking roof tiles, such as Harz-style tiles or similar, would not work.

Currently, the heating system assumes a flow temperature difference of 3 degrees. Should this be reduced?

SierraSix schrieb:
Still, I’m asking about noise, for example from rain.

Well, personally, I think this argument is overrated. Rain is usually only bothersome during the 30 minutes while falling asleep. And it has to be really heavy rain to cause any disturbance. You can calculate how many days there actually are with heavy rain during those 30 minutes.
As someone who has slept for years under a roof window, I can say this rarely happened. Therefore, in my opinion, other factors should be more important.

But to each their own...

klblb schrieb:
Well, personally, I think this argument is overrated. Rain only really bothers you during the 30 minutes it takes to fall asleep. And it has to be heavy, pounding rain to be disruptive during that time. You can calculate how many days it actually rains that heavily within those 30 minutes.

As someone who has slept under a roof window for years, I can say that this rarely happens. So, in my opinion, other arguments should be more important.

But to each their own...

I can follow your reasoning. But since this is only a hypothesis so far, that’s why I’m asking if there are any actual differences or recommendations.

Because there are still uncertainties. For example, how does an aluminum roof respond to sunlight in summer? I mean, metal expands a lot more than concrete, cement, or clay.

Using your example of the roof window, it usually only covers a very small area. But what if the whole room is like having a huge roof window because of a metal/aluminum roof?

As I said, I’m simply asking whether you have any insights where these factors are negligible, or if there are arguments for or against either option… and/or any practical experience or recommendations.

It’s like my question about heating. On the internet, there is a lot of contradictory information: some say keep the supply temperature as low as possible, around 28–30°C (82–86°F), others say 35°C (95°F), and others 40°C (104°F).

Because the extra costs for more closely spaced loops (required with lower supply temperatures) may not pay off.

I’m an absolute newbie here and asking the experts^^ ;-)