2 offers for a single-family house in MV, large difference, is the offer plausible?

Hello everyone,

I now have offers from 2 companies - Provider A 340k€, Provider B 490k€.
Basically, both offers were made for the same house. Due to timing differences in the preparation of the offers and our decision-making phase, there were slight changes to the floor plan, but I want to say that it cannot result in a difference of 150k€. Provider B spoke quite openly in the preliminary discussion about Provider A regarding the quality of the work carried out and stated that regular further training is attended, giving as an example transitions between window and wall, where there is often sloppy work.
I want to build a solid house and accordingly I want a solid basis with good quality in both the materials and the execution. But 150k€?
I have compared the costs.
With Provider A, the electrical work is missing (according to the provider, I should add 6k€) and with Provider B, I did not find the stairs and interior doors; however, construction electricity and water are already included.
I also received a construction service description from Provider A.

What I noticed in the construction service description:
1. I still have to pay the surveyor myself, that is included with Provider B
2. Energy certificate is not included; isn't that a requirement of the Energy Saving Ordinance?
3. I still have to pay for the ground survey myself
4. Roof access window is uninsulated, wouldn't it be more sensible to insulate the attic as well?
5. Hairline cracks in exterior and interior plaster can occur according to DIN; I assume this is correct, but is that the normal case? If yes, can you only see that on close inspection? I cannot assess how relevant that is.
6. Untreated eaves box; that means I have to paint this myself, right?
7. Rainwater drainage: no standpipes; so I have to install the rainwater pipe underground around the house to the central connection myself. Is that normal?
8. Sills/window sills: inside Werzalit, outside powder-coated aluminum; do you want Werzalit inside in a single-family house? But the provider said we can also take granite there. That costs only a little extra. The same applies outside. The provider said that this is not possible otherwise, as the connection to the wall does not work properly otherwise and the insulation would always absorb moisture if you take, for example, granite.
9. Room controller costs 40€ net extra per room; isn’t that a requirement of the Energy Saving Ordinance?
10. Is the wall construction with insulation okay?
11. 60 mm impact sound insulation on the upper floor; is that good? I mean, I don’t want to hear every noise like in my last apartment.

I look forward to your opinions and experiences.

PS: To better assess the whole thing, I am adding the floor plan and views:

What I notice.... speaking badly about the competitor is a no-go. Speak well about yourself, remain silent about the competition. Whoever does not heed this would be out with me. Description of construction services, there is a need to talk. I would go through everything point by point with the BU. We want to build together, this is one of the biggest investments in my life, for you everyday life. Therefore, I ask you to sit with me for another hour and clarify the following in the construction service description. Then you say everything that is unclear or would need to be defined differently. In the end, you have the real price. Then shake on it or, sorry, not possible, I can’t do it. Cracks in the plaster will appear. Due to drying. No problem. After one year, fill in again, paint over, done. Karsten

Hello Karsten,

yes, I also don't like it, but I really can't afford to exclude him just because of that, since there aren't many builders in our area. And just because he may not be so competent on a personal level, maybe he can still build better than others. I think the main thing is that my house is solid.

I will go through the construction specification with him again anyway and also talk about the prices, but with a little more knowledge it's of course easier to discuss.

Regarding cracks: So basically you shouldn't paint right away but wait a year, after filling and only then paint the house? Maybe no one does that because of the appearance but purely from a practical/economic point of view.

Due to timing differences in the offer preparation and our decision-making phase, there were small changes to the floor plan, but I would argue that it cannot result in a difference of €150k.

No, what we have discussed here cannot cause such a spread. Technically, we have not made anything significantly more complex, nor has the volume increased substantially.

What strikes me.... badmouthing the competitor is a no-go.

Whoever really is the better one can calmly wait for word of mouth to direct the competitor’s potential customers to them. Those who complain about the alleged shoddy workmanship of the competitor often actually cite their own complaints and think that if they are more expensive, the other would be considered the worse one. That sounds very much to me like a sly fox

but I really can’t afford to exclude him for that reason alone, since there aren’t many construction contractors in our area.

Yes. In spirit, decisively crossing him off the list of honorable builders is probably the smartest decision. In a few years, everyone will ask you how you recognized the charlatan first

Have the construction service description checked by a professional, e.g. a construction expert. It doesn't cost much, but afterwards you will know exactly what is missing. Have the house construction contract checked by a specialist lawyer; the company can already provide you with a draft.