ᐅ Have a pre-fabricated basement built by a different company?

Created on: 10 Mar 2015 08:44
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charlyuspoll
How do prefabricated or solid house manufacturers generally view it if the basement is built by another company (such as Glatthaar) or similar? Are there any issues with this?
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charlyuspoll
10 Mar 2015 19:39
The following is included in the construction and scope of work description

Basement

A layer of gravel and sand is placed or a plastic sheet installed beneath the basement slab as a clean layer. The reinforced concrete slab is poured using a 20 cm (8 inches) thick dense, waterproof concrete mix. The basement perimeter walls are made of 30 cm (12 inches) thick reinforced concrete walls with waterproof concrete. The joint between the slab and the reinforced concrete exterior walls is sealed with embedded metal sheets to prevent water infiltration at the connection points. The interior walls are constructed from 17.5 cm (7 inches) and 11.5 cm (5 inches) thick sand-lime bricks with smooth mortar joints. Reinforced concrete interior walls are also available as an option. The basement ceiling is formed with a precast reinforced concrete panel ceiling, which is then concreted in place. All basement rooms receive a bonded screed floor finish. Access doors are standard type doors. Each basement room is equipped with a moisture-resistant electrical outlet and a heating connection point. The finished height of the basement level is approximately 2.10 m (7 feet). A reinforced concrete staircase with a 26 cm (10 inches) tread and approximately 17 cm (7 inches) or 18 cm (7 inches) riser with smoothed steps leads to the ground floor. Basement windows and light wells are installed as finished factory-made elements with pressed grating covers and burglar protection.

Your basement is estimated to cost €59,000, is that acceptable?
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Bauexperte
10 Mar 2015 21:34
You probably mean that "this" basement is supposed to cost €59,000. Is that okay?
charlyuspoll schrieb:

The following is stated in the construction and service description

Usable Basement

As a leveling layer below the basement slab, a gravel and sand layer is installed or a plastic sheet is used.
“Or” a plastic membrane? Are you sure?
charlyuspoll schrieb:

The reinforced concrete slab is poured with a 20 cm (8 inches) dense, watertight concrete mix. The basement perimeter walls consist of 30 cm (12 inches) thick reinforced concrete walls made of watertight concrete.
That’s a tricky formulation; I don’t see that you have purchased a “white tank” (fully waterproofed basement shell) as such—if you have assumed that so far. Nowadays, especially with sandwich construction methods, watertight concrete is commonly used. However, it is generally only suitable for normal ground moisture. A true “white tank” requires special sealing according to DIN standards anyway (depending on the foundation recommendations from the soil report), a lot of additional reinforcement (calculated by the structural engineer), and a stainless steel grounding conductor.

I can’t go into the entire basement description now, but my gut feeling is that €59,000 for the above-mentioned scope of work is quite steep.

What about light wells?
Drainage beneath the slab?
Necessary excavation and backfilling?
Soil report?
What if the structural engineer deems 20 cm (8 inches) slab thickness insufficient?

Regards, Bauexperte
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charlyuspoll
10 Mar 2015 21:42
Sorry, I just noticed that the so-called white tank (watertight concrete basement) costs an additional 3800 € (euros).