pressing groundwater / basement yes or no?

My girlfriend and I are facing the big question... Basement yes/no?

We have already had a soil survey done for the property and are now wondering if it makes sense to build a basement there.

I would really like to have a basement (not a living basement). Mainly because of my 6 bicycles, which were not exactly cheap, and the desire for a workshop. My girlfriend is somewhat put off by the pressing groundwater when it comes to building a basement. She is afraid that the white tank won't hold and that building such a basement on our property will be very expensive.

On the other hand, building a slab foundation on the property is also not easy, as the soil would have to be removed first.

I have already read through all kinds of forums and am aware of the risks of a WU basement with pressing groundwater. However, I don't think I can really save money by building without a basement, since I would prefer a large garage with an annex instead of a wooden carport for that.

What do you think? Is building a basement on our property really risky and expensive? Is it cheaper to do without a basement and instead build a large garage with an annex?

Oh, I see. The plan is a single-family house with about 150-160 sqm / the plot is 550 sqm large

The question is something no one can really take away from you. You are surely aware of the advantages and disadvantages. We also have pressing groundwater and decided against a [weisse Wanne] and therefore also against a basement. Instead, we are building a bit higher and have plenty of storage space under the roof. However, we don't have 6 bicycles (although, if I count them all together, we actually do). If I were in your place, I would plan the garage a bit bigger and also accommodate the workshop there; that way, you won't have to carry the bikes up and down. Your property should be large enough for that.

Hello,

My girlfriend and I are facing the big question... Basement yes/no? Planned is a single-family house with about 150-160 sqm / the plot is 550 sqm

On the other hand, building a slab foundation on the plot is also not exactly easy, as the soil would first have to be removed.

You don’t just have to remove soil, there is also actually soil missing

I have already read through all kinds of forums and am aware of the risks of a waterproof basement with pressurized groundwater.
However, I don't think I can really save money by building without a basement, because instead of a wooden carport I would like to have a large garage with an annex.

A waterproof basement executed according to DIN 18xyz according to the soil survey carries no risks. If you two are so anxious, you should commission external experts as support for the builder.

What do you think? Is building a basement on our plot really risky and expensive?

More expensive than on "normal" plots, yes. Risky - with technically flawless construction: no.

Is it cheaper to do without a basement and instead build a large garage with an annex?

Under normal conditions: always. Due to the additional foundation costs on your plot, however, the basement will become yet another "notch" more expensive. I estimate about EUR 42k for the usable basement and then another good EUR 8-9k for the required sealing.

I haven’t recalculated how many centimeters of soil need to be exchanged and backfilled for the slab foundation. But even if this position also requires EUR 8-9k, the prefabricated garage costs 3 x 9 all in EUR 10k; realistically a saving of EUR 23k compared to a usable basement.

In the following link you will find excerpts from our soil report

It would be nice if the next download offer could be realized without undesired background noise

Rhenish greetings