ᐅ Cost of Foundation Slab for New Construction in Hesse

Hello everyone,

We are currently in the planning phase of our new house construction in Hesse, in the Rhine-Main area. We are planning to build a detached house in the second row on a property we own. At the moment, we only have two house manufacturers left in the running, and as is often the case, both offers start from the foundation slab. Therefore, we have also received an offer from a company for the construction of the foundation slab; this company was recommended to us by one of the house manufacturers.

I wanted to ask if anyone could help me by telling me whether the offer includes everything and whether the price is reasonable. It should be noted that there is no soil survey yet (but it will be commissioned soon), so excavation costs are not yet determined. Furthermore, we will hire a building surveyor who will review the construction specifications, the offer, and the contract and will also supervise and monitor the construction.

But now here are the costs related to my original question.
Reinforced concrete foundation slab 98.5 sqm (1060 sq ft) floor area

• Structural calculation in verifiable form
• Professional site management
• Drainage
• Laying of sewer drainage pipes under the foundation slab without backwater valve
• Batter boards
• Setup for precise building location by the surveying office commissioned by us or a survey engineer
• PE (polyethylene) foil
• Installation of a PE foil on the base layer
• Reinforced concrete slab
• The slab is built according to structural calculations including necessary reinforcement with a thickness of 25 cm (10 inches), concrete grade C25/30
• Frost protection footings
• Concrete C25/30, including earthworks
• Foundation earth electrode
• 5 m (16 ft) of conduits for utility lines
• 12,000.00 EUR

Base layer

• Installation of a 15 cm (6 inches) thick capillary-breaking layer under the foundation slab, gravel grain size 11/22
• 940.00 EUR

Rainwater drainage

• Installation of rainwater drainage system with PVC pipes diameter 100 mm (4 inches), including necessary earthworks
• 1,550.00 EUR

Sewer connection

• Creation of the sewer connection on the property including delivery and installation of an inspection chamber consisting of:
• Concrete base
• Cleaning opening, open channel
• Concrete shaft rings, diameter 100 cm (39 inches), with ladder rungs
• Shaft cone 100 / 60 cm (39 / 24 inches)
• Cover rated for 5 tons
• 18 meters (59 ft) of trench excavation with backfill up to the street as a stepped trench, PVC pipe diameter 150 mm (6 inches) with necessary fittings
• 3,560.00 EUR

Rainwater cistern

• Usable volume 6,600 liters (1,745 gallons)
• Base and surrounding fill for infiltration using grain material 11/22 (soil must be suitable for infiltration), covering the grain material with a filter fleece, vertical PVC pipe diameter 200 mm (8 inches) with closure cap for checking the infiltration function, including earthworks
• 2,870.00 EUR

Any tips or advice would be very helpful.

Thank you in advance!
Christian

As I understand it, a proper blinding layer is not a "15cm (6 inches) capillary break layer made of gravel."

The blinding layer (e.g., 5cm (2 inches) of C12/15 concrete) is placed on top of the capillary break layer.

And then the vapor barrier is installed on top of that.

Hello emer,

thank you for your reply. To make sure I understand correctly, from your perspective, for example, should a 5cm (2 inch) thick concrete layer be placed on the capillary-breaking layer, and then the floor slab on top of that?
Can you provide a statement regarding the prices, whether they are within the expected range?

No one can tell you if the costs are reasonable. Basically, you now need a quote from a second company. The problem is that it can be difficult to compare the quotes. However, I would recommend getting a second or even a third quote. Be careful, though, as it can happen that the one who wins is the one who leaves out the most from their offer and then makes additional claims later.

And that raises the question of whether this offer includes everything.

Bricktop schrieb:
Hello emer,

thank you very much for your reply. To make sure I understand correctly, from your point of view, should a 5cm (2 inch) thick concrete layer be placed on the capillary break layer, and then the slab on top?
Can you comment on whether the prices are within the expected range?

In my opinion, the blinding layer was missing in your case. A plastic sheet or gravel is not a blinding layer.

Construction sequence: gravel, concrete (as described above = blinding layer), plastic sheet, slab.

Your soil report should also include a foundation recommendation.

Only then does it make sense to request quotes.