ᐅ Evaluation of Two Contractors or Construction Services

Created on: 12 Feb 2017 12:24
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Wissi
Wissi12 Feb 2017 12:24
Hello everyone! On our way to building our prefabricated house, we received/compiled two offers yesterday.

First from Schwörerhaus and then from an acquaintance (father of a friend) who works for Schwabenhaus. The latter suggested that we bring the Schwörerhaus offer to him, and he will try to match everything and offer us a better price. But beware: with a brine-water heat pump (ground source with probe). I’ll go into the details shortly and would like to hear your assessment on this.

I’ll try to keep everything as clear as possible. The comparison is always based on details from the construction and service descriptions of Schwörerhaus versus Schwabenhaus.

The most important point -> Heating

Schwörerhaus: Air heating with low-temperature heat pump + additional heating elements at the outlets.
  • Air heating: heat recovery 134 BP-HK
  • Domestic hot water via additional low-temperature heat pump with electric heating rod (2.5 kW)
  • I’m not very enthusiastic about this!
  • It’s also possible to have a low-temperature heat pump with underfloor heating (extra cost) or a brine-water heat pump (ground source with probe) combined with the air heating (of course also extra cost)
  • Additional costs have been requested

Schwabenhaus: Brine-water heat pump ground source (probe) with underfloor heating.
  • Domestic hot water also via this system
  • Annual performance factor given as 4.7 (unit by Waterkotte)
  • They also mention the 5000 euro bonus, which after a quick online search seems to be available to everyone anyway

Both already include mechanical ventilation.

If it were only about this, our decision would be clear and obvious: Schwabenhaus. However, there are also disadvantages because the “same price as Schwörerhaus” somehow has to be compensated elsewhere, and we believe this happens in the following areas. I’m uncertain about these points and would like to ask again for your opinion.

Exterior and Interior Walls

Schwörerhaus: Exterior (total thickness of 32 cm (12.6 inches))
  • Insulation thickness of 240 mm (9.4 inches), inside with wood fiber board + gypsum board
  • Outside: solid building material “Cospan” with an additional vapor-permeable layer
  • Plaster carrier: 40 mm (1.6 inches)
  • U-value: 1.5

Schwabenhaus: Exterior (total thickness: not explicitly specified)
  • Insulation thickness of 160 mm (6.3 inches), inside directly gypsum fiberboard
  • Outside also only gypsum fiberboard
  • Plaster carrier: 100 mm (3.9 inches) as full thermal insulation board
  • U-value: 1.4

Inside is similar: with Schwabenhaus directly gypsum fiberboards (12.5 mm / 0.5 inches) on the wooden structure, while Schwörerhaus uses wood-based panels (16 mm / 0.63 inches) behind the plasterboard (9.5 mm / 0.37 inches). I’m a bit skeptical about load capacity with Schwabenhaus’s version. Also, in terms of sound and insulation, I’m not quite sure. The ceilings also seem to be somewhat “lacking” in comparison…

The following details are missing from Schwabenhaus’s construction and service description. Since I’m not an expert, I find it difficult to assess these and maybe you can also help here:
  • No storm anchors/clips
  • No KfW certification or blower door test mentioned in the construction and service description
  • Transport costs of the house, assembly crane, the assembly itself, scaffolding, residual waste container including disposal, construction site toilet, registration and completion notification of house connections are missing in Schwabenhaus’s construction and service description (listed separately by Schwörerhaus)

Of course, I have already asked these questions to the Schwabenhaus consultant as well. I assume that if something is not included in the construction and service description, it is simply not included in the scope of services. If you want it => extra cost … or you have to arrange it yourself.

How would you assess this whole situation? What would be important to you, or what doesn’t seem too serious (e.g., the wall issue) … or what would you rather not recommend?

Thank you very much for your time and advice!
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Nordlys
12 Feb 2017 12:43
Request it and have it documented in writing what is missing. Regarding the wall construction: Schwörerhaus is probably better for wall cabinets, but I cannot say whether the other option from Schwa also works well in practice. The vapor-permeable layer in Schwörerhaus is certainly beneficial, as it helps prevent mold and possibly facade algae growth, provided it actually performs as intended. Allows for breathing.
Wissi12 Feb 2017 12:49
Thank you for your assessment!

A few additional details I forgot:
  • Both houses are KfW55 standard
  • Price should be the same for both, so it was excluded from the calculations

If all the additional features later result in a higher price with Schwa., we tend to lean more towards Schwö. We have the feeling that their offerings provide slightly better quality, durability, or more "substance" :-/
And, if possible, we would like to get the combination of SW heat pump + "air heating" there.
M
motto65
13 Jun 2019 00:18
Hello Wissi,

how did your research turn out, especially regarding the open questions in the first post, specifically about the unresolved, undefined issues with Schwabenhaus?
Wissi13 Jun 2019 07:03
We ultimately decided on Schwörerhaus but opted against the air heating system. Instead, we installed underfloor heating combined with an air-to-water heat pump.

The package offered by Schwörerhaus appealed to us more overall.