Assessment of incidental construction costs for a 150 sqm single-family house with a basement

Hello everyone,

we are currently doing the cost calculation for our construction project in Rhineland-Palatinate and would appreciate your assessment of our ancillary cost calculation:

The construction project is a solid prefabricated house with a full basement and 150 sqm of living space + utility basement. The dimensions of the house are 10.5x9.5m. Moderate slope (gradient not yet measured) descending below the street.

Are the following ancillary construction costs realistic, or is there perhaps too much/too little calculated?

Ancillary construction costs	Total ancillary construction costs
Building permit	1,500.00
Screed heating program	1,500.00
Construction electricity/water	1,000.00
Civil engineering work, preparing outdoor facilities, disposal costs	30,000.00
Outdoor facilities + furniture	12,000.00
Water-electricity connection, multi-utility, telecom	5,000.00
Sewer connection	4,000.00
Backwater protection	2,500.00
Soil report	included in house price
Financing costs	1,000.00
Insurance (builder’s liability)	250.00
Surveyor services	4,500.00
Carport with house connection	15,000.00
Kitchen	15,000.00
Total	93,750.00

Are the earthworks realistic? This is the last house in the new development area and there have been no problems with the soil at the neighbors. The information on the internet ranges from 15,000 to 30,000 for comparable situations.

We were also wondering if backwater protection is necessary?

The italic values are actually not ancillary construction costs but are to be financed together, which is why they are listed.

We would be very grateful for assessments!

Best regards,
K+A

Is the groundwater far enough away for the basement, or do you possibly still have to pay for a groundwater lowering?

I would already consider the item [Außenanlagen und Möbel] absolutely insufficient for a towel-sized plot of land with zero slope. In my opinion, when it comes to a slope, it is only a drop in the ocean.

Groundwater is far enough away.

And the outdoor facilities are initially only the essentials, which are co-financed at the beginning. The rest will be done later with a lot of personal work and friendly garden landscapers.

What does "the bare minimum" mean to you? You at least have to gravel the driveway and paths. Slope reinforcements are not optional. The splash guard around the house shouldn't wait for 3 years either. And additional work done by yourself later on also costs money for materials, is there enough reserve planned for that?

What do you mean by €1000 financing costs? But at the notary, you only get a relatively small land charge issued for that. And the land registry office wanted more money again.

€250 for insurance is very tight. You don't just need liability insurance but also construction all-risk insurance. €1500 for screed is also questionable, at the current price of 50c/kWh you get only about 3000 kWh for that. I find it hard to estimate civil engineering, but it also seems rather low if waste removal and some preparatory work for the outdoor facilities are included. Utility connections are also rather tight, but this strongly depends on how much distance you have.