Questions/neglected plot/meadow, determining construction measures

Hello everyone,

we are very interested in a plot of land near us. It is a building gap in a general residential area. I have a few questions about it:

The plot is 21m and 31m long. According to the seller, there is a slope of about 1m on the 21m width. Can this cause problems during construction or can such a slope be easily compensated? We want to build a detached single-family house with a basement.

There used to be a residential house with a basement on the plot, but it was completely demolished years ago; now it is just a green meadow. Can unexpected problems arise from this? What do we need to pay attention to?

How can we find out if any construction measures (sewer, road surface, etc.) are planned on the street and whether costs might possibly be incurred by us?

I look forward to tips from you!

To answer your questions, you will first need to have a soil survey conducted. 1 m should not be a problem, especially if a basement is going to be built. But what you should investigate if an old house once stood there: did they simply bury the construction debris? Was the soil properly compacted again? From what depth does load-bearing ground start, groundwater? With that, you can identify the cost drivers for the property. Or at least narrow them down. You always have to expect costs from the municipality. You should definitely keep money in reserve for that. You can inquire with the municipality, but that does not always lead to success. We had to settle a bill from 1962 that no one had told us about. There was an unpaid water connection from back then on the property, which we had heard about, but no one at the office could or would give any reliable information. After digging it up, the papers at the office also came to light again: Result: €11,000 bill. We swallowed this bitter pill because our property was very cheap and well below the prices traded at that time.

Hello,

since you want to build with a basement, the slight slope of 1 m over the plot width of 21 m should not be a problem.

It would just be possible that the basement sticks out a bit more from the ground on one side of the house than on the other side...

A demolished house is basically not a problem. You should just make sure that the ground is not contaminated – for example by a leaking oil tank or other pollutants from the old house.

Any connection fees can be informed to you by the responsible city or municipal administration. I would also ask there whether there is a development plan or, for example, §34 Baugesetzbuch applies.

Regards,

Dirk

Hello Dirk,
thank you very much! I was already hoping that a 1m difference doesn't matter much. I don't find it problematic if the basement sticks out a bit on one side. I think on that side we could then plan large windows in the basement/souterrain, so that we can definitely have a very well usable basement room (office/guest room).

Does a soil survey say anything about a possible contaminant load or is it only about water/load-bearing capacity of the soil?

There is a development plan, which I also have. Therefore, I also know that it is a general residential area, and apart from detached buildings and single- or two-family houses, not much is specified. Two full floors are possible, roof shape doesn't matter, the building envelope is 14m deep, so all that fits.
But the development plan doesn't say anything about possible road construction measures, which is why I asked about it.

Hello,

The plot is 21m and 31m long. According to the seller, there is a slope of about 1m on the 21m width. Can problems arise during construction because of this, or can such a slope be easily compensated? We want to build a detached single-family house with a basement.

Easily compensated for, certainly; cost-wise, "it can" – even with a basement – result in a nice sum of additional expenses in the end; it depends on whether you have to compensate or if the plot can continue to slope gently. If the property is located in a water protection zone, it will be even more expensive because, for example, no recycled materials may be used.

There used to be a house with a basement on the plot, but it was completely demolished years ago, now it is just a green meadow. Can unexpected problems arise from this? What do we need to pay attention to?

"Actually" no, if the demolition contractor back then worked cleanly and did not bury any construction debris. Whether the soil is load-bearing or not plays only a minor role when building with a basement and depends mainly on how deep the former demolition contractor excavated.

How can we find out whether any construction measures (sewer, road surface, etc.) are planned on the street and whether costs might be incurred for us because of this?

The easiest way is to ask the selling municipality. Whether the plot is sold including development costs or without – those are the two crucial questions to be asked.

I do not mind if the basement sticks out a bit on one side. I think that on that side we could then plan large windows in the basement/semi-basement, so that we can definitely have a very well usable basement room (office/guest room).

That depends on your budget. If the basement costs – here fully developed in this case – jeopardize your construction budget, considerable additional foundation costs will arise; you will have to compensate about 1.00 m across the entire area.

Does a soil report say anything about possible pollutant contamination or is it only about water/load-bearing capacity of the soil?

Usually, the soil conditions are examined regarding load-bearing capacity. However, you can always extend the soil report to include the determination of pollutant contamination. Here I would first try to locate the demolition contractor from back then. If the demolition was less than 10 years ago, he should still have the documents.

... and except for open construction and single- or two-family houses, not much is prescribed. Two full floors are possible, roof shape is irrelevant, the building window is 14m deep, so that all fits.

Do you want to use the entire building window and build a full basement? What are your ideas regarding the construction costs?

Rhenish greetings

Hello Panama17,

that doesn't sound too bad.

You can order the soil survey however you want - normally only the load-bearing capacity and water situation are checked, but of course you can also have it tested for pollutants.

A first point of reference would be a conversation with the neighbors who still remember the demolished house. Perhaps the seller can also tell you if the old house, for example, had an oil heating system and if the old oil tank might still be in the ground in the worst case.

Regards,

Dirk