Prefabricated house provider selection experiences?

Hello everyone,

after all this time, the uneasy (one of many) moment is slowly coming when we have to decide which provider we ultimately want to work with. Here are a few key facts:

New development area, development according to development plan:
Semi-detached house with shed roof, north-facing, 230 sqm plot, basement, ground floor, upper floor, attic, roof pitch 10-12°, air-to-water heat pump is fixed, ventilation system (we are still unsure whether it is really necessary), approx. 160 sqm living space. It was important to us to have a staircase with a landing; otherwise, we have no special requests, possibly a floor-level shower in the master bathroom, but that’s it. We have to build an unnecessarily large balcony, 7 x 2.5 m.

We are very concerned that because of the south orientation of the garden terrace, which has no shading at all, we will bake inside the house in summer. We then researched back and forth and found out that regarding heat protection, insulation with mineral wool is the worst. The frequently installed polystyrene insulations are better, but also not really good. The best and still reasonably priced would be wood fiber insulation. The roof should also be insulated with this as much as possible. And yes, we also want to retrofit shading with awnings on the windows, but the question about the wall structure remains.

After several selection rounds and countless inquiries, only four providers remain who could fulfill all our and the requirements of the development plan.
These are Haas and Fischer Haus (both with 40cm and 36cm thick exterior walls with polystyrene, wood fiber is not offered), as well as Lehner and Keitel-Haus (they have wood fiber insulation in the exterior walls, 25cm and 34cm).

Apart from that, all four can do roughly the same. (Our floor plan, a certain portion of own work, electric shutters, roof pitch 10-12° and covering with clay/concrete tiles, scheduling). Provided we can even compare the final prices, there remains a difference of about 25,000 euros at the end. We want to carry out excavations and the basement if possible together with our neighbors. They will most likely build with Haas, which is how Keitel-Haus came into our considerations.

Pro/Con Haas: + Neighbors build with them, synergies, approx. 17,000 price savings/discounts
+ appears large and reputable, but not too big like pure capital companies
- very thick walls (loss of living space),
- no wood fiber insulation
- most expensive offer of all four

Fischer: + very structured and tidy offer
+ company size similar to Haas
- no wood fiber insulation

Lehner: + wood fiber insulation
+ always responded immediately without restrictions to our requirements and questions
- allegedly only one afternoon for sampling, seems very short to us
- somewhat confusing offer with unclear options

Keitel-Haus: + wood fiber insulation
+ 34cm thick walls for heat and cold protection
+ cheapest provider
- there was no preliminary discussion as with the approximately 12 providers before, they only came into consideration through the neighbors
- seems like a small shop, even the sampling looks squeezed into a private apartment

So... how should we decide? The prices are only binding for a few more days or until the end of August; two have already threatened, uh, announced price increases ;)

but the question about the wall structure remains.

Why? You have probably now examined "all" prefabricated house providers. Why do two come into closer consideration, whose insulation (wall structure) you are not convinced of? Why do you have to build a balcony? In the meantime, I consider a ventilation system a must with tight buildings. A 25 cm exterior wall (wood stud?) is no longer up to date. Did you each present your floor plan to them? By you or an architect? Can it be seen here somewhere? Sensible wall structure, roof insulation, blinds and ventilation system and summer can come. Appropriate windows should not be up for discussion.

Why are two candidates shortlisted whose insulation (wall construction) you are not convinced of?

Based on the other threads, the price is likely the deciding factor. Although I still wonder why building is happening at all. That was already a problem with the figures back then, and with the interest rates and construction costs today, it's definitely financial Harakiri.

I hope others will also speak up. I just had a phone call with Mr. von Haas, who unfortunately told us that our idea of polystyrene completely on the outside combined with wood fiber insulation board inside as insulation in the wooden frame is NOT possible, supposedly due to fire protection. Strangely enough, it would apparently be allowed for a single-family house but not for a semi-detached house. Burning on its own is okay, but the neighbor must not burn along.. hmm.. I have my doubts as if fire, once it really flares up, would really be stopped by such technicalities. Therefore... either the variant (from the outside) plaster, polystyrene, thin wood panel, wooden frame with mineral wool, or the variant with mineral wool instead of polystyrene and wood fiber board instead of mineral wool in the insulation (rest the same) at an additional cost of €14,000. That is roughly the exact price difference between Haas and Keitel-Haus.

Why? You have probably now reviewed “all” prefabricated house providers.

Certainly not all (about 50 + x small carpentry businesses), but from about 12 providers we have concrete offers for our floor plan including preliminary discussions. Namely Allkauf Haus, Okal Haus, Bien-Zenker, Hanse, Elk, Fischer, Lehner, Dan Haus, and Haas. Keitel-Haus only came into consideration because our neighbors had them in their shortlist. Initially, they were out for us too, but when we wanted to decline them, we got a "complaint" email ;) that their wall construction would easily beat the cheap one from Haas, etc... then we gave them another chance with the now revised floor plan and lo and behold, they can deliver everything we wanted/needed plus the good wall construction. This is in turn torn apart by the Haas guy, but various sources say that wood fiber can handle water quite well on the outside anyway and offers the best heat protection (among wood fiber, polystyrene, and mineral wool).

Honestly, I’d prefer to lock all the sales representatives in one room with our floor plans and see who survives the argument battle in the end :) We’re just the fools who know little to nothing and they can tell us anything all day long, gladly even the complete opposite of the first thing. :(

Why are two coming into close consideration, whose insulation (wall build-up) you’re not convinced of?

Because all the others were already out for various reasons. We’re really convinced by none! The combination of quality, heat protection, equipment, flexibility, and price is just not good for anyone. But maybe it has to be that way :(

Why do you have to build a balcony?

Requirement from the development plan. We have to build a shed roof in this position and that also results in a bay window with a balcony/loggia. I wouldn’t need one that’s 2.5 m x 7 m in size! At least everyone wants to recommend a whirlpool on it :D

I consider a ventilation system meanwhile a must with these tight buildings.

Yes, I fear so too. It just costs money again and the benefit is.. well... “dependent on belief” I’d say ;) But I can still think about it until the sample selection.

A 25 cm exterior wall (wooden frame?) is no longer state of the art.

Why? Because too thin or too thick?

Did you present them with your floor plan? From you or an architect?
Can it be seen somewhere here?

Yes. We created it with Roomsketcher. Obviously, it’s not a hardcore architectural CAD program, but it’s great for drawing rooms, furnishing, and even seeing how it looks in 3D! We of course included measurement data plus information about window sizes, etc. We then had offers from 10 providers. Unfortunately, we made the mistake of assuming the outside and inside walls would be too narrow, which nobody offers. And as soon as we put the walls in anew, the layout no longer worked and we had to redesign everything. But now we have the new layout and again offers from the last 6 providers; two of those have dropped out, leaving 4.

Proper wall construction, roof insulation, blinds, and ventilation system and summer can come. Appropriate windows should not be up for discussion.

The windows were quoted to us by everyone with a U-value of 0.5. Triple-glazed with plastic frames. So there should be no difference. We definitely want to equip all south and west windows with awnings now.

Though I’m still wondering why you’re building at all.

Because the need is there! We want a second child, number 1 has already claimed everything anyway. Why don’t we buy an existing building?? Well, without offers, I can’t buy anything either. The market is swept clean. Houses south of Ingolstadt to Regensburg simply don’t exist with the equipment (room count, sqm, year built). Then the only option would be to move away massively and we don’t want that if it can be prevented somehow. I know... EVERYONE says that now is probably the worst possible time to build, but as I said... the need is there :/

Regarding financing: We will probably be lucky now to get some unexpected major support from family in the form of a private loan, which would exclude banks entirely. But that’s not 100% fixed yet.

Why? Because too thin or too thick?

The question is not serious now, is it? :rolleyes: And what do you want with interior insulation? If you have really intensively evaluated all providers here, compared, had talks etc…. that certainly took (or takes) about 2 years. What do you always want with awnings anyway? I would start with the floor plan. Please show it. Quality and "costs little" you will not find. There are still one or two interesting providers (from my point of view).

Why actually the stiffening on prefabricated house?