ᐅ Bought an old basement. Is it supported only by wooden studs, or does it also have solid masonry construction?

Hello everyone, a few weeks ago we purchased a plot of land with a basement (built in 1989). The house above it was removed after a fire last year. Apart from the fire-fighting water, the basement was not affected and is in good condition. Previously, there was a 1.5-story wooden house on it. We would prefer to build another 1.5-story house and are currently in discussions with various home builders (solid construction & light-frame construction). One of the solid construction builders has pointed out that the foundation would only support one floor (ground floor) if we go with solid construction, meaning the attic floor could not be developed.

Are heavily insulating pumice or Poroton bricks really that much heavier?

The basement is a prefabricated reinforced concrete basement, but only 14 cm (5.5 inches) thick throughout. The overall exterior dimensions are 11.5 m x 11.5 m (38 feet x 38 feet). The foundations are unreinforced strip footings B 15, measuring 30 x 50 cm (12 x 20 inches). Concrete slab B 15.

We have all the structural engineering plans ready but I don’t know what to look for.

Before contacting more solid construction builders, I would like to know if solid construction is even an option for us. Is it possible to roughly determine this from the plans without immediately hiring a structural engineer?

Best regards from the Pfalz

Hello Olli,
You won’t be able to manage this without a structural engineer. Trying to comment on it from a distance won’t help you! The engineer is the expert who can assist you, and such a decision might only take about an hour.

A timber frame panel house nowadays is not significantly lighter either; they no longer have the wall thicknesses that were common thirty years ago or more.

OlliQueck schrieb:

Otherwise, basically everything is available:
- Architect’s plans
- Expert report describing the materials and construction method

Then please show both here.

OlliQueck schrieb:

The basement is a precast reinforced concrete basement, but consistently only 14 cm (5.5 inches) thick,

Given the construction year, I find that hard to believe even for a timber house. But with drawings, I might understand better; the photos from your other thread are not sufficient for me.

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11ant schrieb:

A timber frame panel house nowadays isn’t significantly lighter anymore; they don’t have the wall thicknesses they used to have thirty years ago or more.

Then show both here.

Given the year it was built, I find it hard to believe it’s a wooden house. But maybe I’ll understand more with drawings; the pictures from your other thread aren’t enough for me.

Alright, here are the plans. The wall thicknesses on the architect’s plan are not correct in terms of width, but those on the structural engineer’s plan are exact (measured manually).

OlliQueck schrieb:

Alright, here are the plans. The wall widths on the architect’s plan are not accurate, but the structural engineer’s plan is exact (measured manually).

I don’t fully understand the plans, specifically: there are two basements shown. In the drawings that also include ceiling slab plans, it looks like a concrete basement with walls as thin as the ceilings. But the individual basement plan from Breisgau Haus (which apparently belongs to a "timber house") and unfortunately without structural details, seems to show a masonry basement with an exterior wall thickness of 36.5 cm (14 inches), which, regardless of the exact building material, should also be able to support a house with the same wall thickness. Which of these two basements was actually built? Was the masonry basement only offered initially, and then the client decided on a prefabricated basement instead?

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https://www.instagram.com/11antgmxde/
https://www.linkedin.com/company/bauen-jetzt/

So, if we understood correctly, the architect from Breisgau House originally planned a masonry basement, but what was actually built is a precast concrete basement—the one used in the rest of the plans.
I have attached the Breisgau House plan again just so you can see how the basement is being used now, including the room layout, etc.

A builder told us that concrete can carry more load, which is probably why they were able to replace the masonry walls with thinner concrete walls in the planning back then.