ᐅ Construction costs when building with an architect. What has your experience been?

Of course, he can delegate parts of the work, but certainly not to the extent that the general contractor actually removes him from the construction site — although there are occasional rumors that this is sometimes attempted.

Toppi, where in Baden-Württemberg are you building? I’m also from the area and find your land price interesting. Feel free to send me a private message.

Hello,
I am currently planning to build a house as well. If the building authority in Waiblingen ever wants/can/process the application.

Last year, I explored both prefabricated houses and solid construction.
I want to build a two-story house with a raised ground floor, a granny flat, and an expandable roof. Concrete stairs.
Commercial rental with enhanced soundproofing or holiday apartments.

The prices for the high-quality shell construction through general contractors
for timber prefabricated houses ranged between 280,000 € and 400,000 € and differed depending on whether it was wood flooring or concrete floor.

The solid house made of aerated concrete costs between 260,000 € and 750,000 €. The economical version is offered as a refined shell, the expensive version as a worry-free package.

I decided on the affordable solid component. The offer I liked best was based on VOB with a quantity take-off. It involves a concrete master builder with a designer (structural engineer). The entire house, including garage and individual room forced ventilation, will come to about 500,000 €, and it is individually planned by me.

I really wouldn’t recommend my approach to anyone inexperienced. The architects' billing follows the fee structure for engineers and architects. It costs around 20 € in bookshops. Everything is nicely listed there. Negotiate the category with the architect. Also, specify that everything is included: no copying, office, or other extra costs.

Keep in mind that for almost everyone, specialist planners, connections, building authorities, utility companies, etc., are charged separately. This often adds up to a significant extra expense.

Prefabricated houses have many advantages, especially if you only use them as a private home. Cables and pipes can be laid very easily in the installation level. But seriously: do you believe manufacturers that the insulation will retain its elasticity to insulate everywhere after 20 years? I have seen too many water ingress issues in existing prefabricated houses on closer inspection.
A solid house is also more effective at heat and cold protection due to its much greater mass.

If I were to build my first house again today, I would go for a turnkey project paid through an escrow account upon moving in. The house handover should be done through an expert.
Garage as a prefabricated garage with a cistern underneath. The cistern has the advantage that only a gravel bed is needed. The garage floor forms the cover.

Best regards from Waiblingen.

Aladelta schrieb:
Prefab homes have many advantages, especially when used solely as a private residence. The cables and pipes can be easily installed within the service cavity. But seriously, do you really trust the manufacturers that the insulation will still retain its integrity after 20 years to provide consistent thermal protection? I have noticed too many cases of water infiltration when closely inspecting existing prefab houses.
A solid masonry house, due to its much greater mass, is also slower to respond to heat and cold, providing better thermal stability.

Sorry, do you actually have any real knowledge about what you're talking about here?

For example, why would wood fiber insulation need to retain “tension”?

What exactly does water infiltration have to do with the insulation?

Which building method offers better insulation values, and therefore better protection from heat and cold, at the same wall thickness?

I wish you the best with your concrete construction.

The insulation of prefabricated houses is built up in multiple layers. In three cases, the wall structure offered did not match the one described in the brochure. In all cases, mineral wool was used in the inner insulation layers. This mineral wool provided the highest calculated thermal resistance in the wall assembly.

My question to the prefabricated house builders was: How do you secure the mineral wool against the long-term effects of gravity? The answer was: It is not necessary.

We have the problem that the thermal insulation performance decreases significantly within 10 years, despite good inspection. In some cases, it even halves. We know this from records at power plants. Personally, I am a managing thermal engineer with a degree in process engineering.

The advantage of mass (solid construction) is hysteresis (phase shift between energy input and effect). Since the warming is proportional to the mass, and nowadays heat protection is more important, it is better to shift the warmest point to a time when there is a large temperature difference between inside and outside. For example, this is possible at night from around 2 to 3 a.m. during warm nights. This is how long the house must rely on its thermal mass. This is physics, and it is difficult to argue with.

For those who do not know what hysteresis is, a simple example: On June 21, we have the highest energy input from the sun on Earth, and in August it gets really hot. On December 21, we have the least sun, and in February it is bitterly cold. This means there is a hysteresis of about 2 months on Earth. It is the same in a house. I hope I am not stoned for this.

With that, enjoy the forum. I’ll sign off now.

Aladelta schrieb:
The insulation of prefabricated houses is constructed in multiple layers. In three cases, the wall structure in the offer did not correspond to the wall structure shown in the brochure.

What is this statement supposed to tell me?

Aladelta schrieb:
In all cases, mineral wool was used in the inner insulation layers. This mineral wool provided the highest calculated thermal resistance in the wall construction. My question to the prefab house builders was: How do you keep the mineral wool in place against the long-term effects of gravity? The answer was: It’s not necessary.

Why would it be? If installed correctly, nothing should happen. If mineral wool is really as unsuitable as you describe, I wonder why it is also used as insulation in the roof areas of solid or masonry houses. Are there no effects of gravity there?

Aladelta schrieb:
We have the problem that the thermal insulation performance notably decreases within 10 years despite good inspection. In some cases, it even halves. We know this from records at power plants. Personally, I am a managing engineer in thermal engineering with a degree in process engineering.

Who inspected what here?

Aladelta schrieb:
The advantage of mass (solid house) is the hysteresis (phase shift between energy input and effect). Since the warming is proportional to the mass, and heat protection is the main focus today, it is better to shift the hottest point to a time when there is a large temperature difference between inside and outside. This is possible, for example, at night after 2 or 3 a.m. on warm nights. The house then has to ‘live’ off its thermal mass for that long. This is physics, and physics is not easily negotiated.

Very impressive. If that is true, your solid or masonry house has exactly that undeniable disadvantage: It also takes much longer for a sun-heated (overheated) solid house in summer to cool down again to comfortable temperatures.

Aladelta schrieb:
For those who don’t know what hysteresis is, a simple example: On June 21, we have the highest solar energy input on Earth, but it gets really hot only in August. On December 21, we have the least sun, but it is bitterly cold in February. So the Earth has a hysteresis of about 2 months. And that’s exactly how it is inside a house. I hope I don’t get stoned now.

I can agree with this statement to some extent, but it only applies to the Northern Hemisphere, not the entire Earth, Mr. Engineer…