Screw foundation as a cost-effective alternative to a slab?

I’m going to try it myself right in the first post: We are currently in the first concrete thought steps for a house. Fixed is: it should be made of wood (exactly how is open) and on screw foundations. Actually, we had already chosen a company and had even been to their factory, but they have recently become insolvent... Therefore, my question goes beyond the experiences, I would also like to know if anyone knows companies (except Staudenschreiner, we are too far away from them) that set such foundations or even better build houses turnkey as general contractors. Google is really not very helpful here. I am located in the Trier area, so the carpentry of might even be an option. Many thanks in advance

Hi David! Google wasn’t helpful for us either, at least not with wood floor plates. I then inquired at many different carpentries in the area and some already had experience with something like that. But they just hadn’t advertised it on their website. So it’s quite possible that you’ll also find someone among the “regional” carpentries near you who can do that or has even already done it. Our house builder was open to it at first, he would have also built it with the help of Staudenschreiner, but eventually waved it off because it would probably be too expensive... But you do have screw foundation companies? Regards Pascal

Hello Pascal,

we would prefer to have everything from a single source, at least the foundation and the shell construction. For this reason, we have not yet looked for companies that only install the screw foundations. I have not pursued the idea of simply contacting carpentries for the same reason, but I will probably have to do so if I can't find anyone for a complete package. In the meantime, I have also scheduled a few initial meetings with companies, and despite my mention of the screw foundation, none of them have withdrawn.

Best regards

Hi,

now that you mention it, one carpentry company also took care of the [Schraubfundamente], but I already have an offer for that, so they don’t need to do it anymore. However, it shouldn’t be a big deal, the manufacturers are known and they can coordinate among themselves. Whether you find a carpentry company that also "sets" the [Schraubfundamente], that will probably be a longer search! Good luck and feel free to keep me updated.

Hello Pascal,

we would prefer everything from a single source, at least the foundation and shell construction. For that reason, we have not yet looked for companies that only install the screw foundations. I haven’t pursued the idea of simply contacting carpentry companies for the same reason, but I will probably have to do so if I can’t find anyone for a complete package. In the meantime, I have scheduled a few appointments with companies for an initial meeting, and despite my mention of the screw foundation, none of them have backed out.

Best regards

Hi David,
a brief update from us: unfortunately, we are no longer pursuing the idea of screw foundations / wood floor slabs. Since we don’t have an architect, I had to take care of everything, and some important information was "overlooked" by me or I did not inquire about it in depth. We received the structural analysis of the house – the concrete floor slab builders will calculate their own structural analysis. That’s also what the house builder communicated to me. Unfortunately, the carpentry companies see it differently, and having the structural analysis recalculated would nullify the potential financial advantage of the screw foundations & wood floor slab. We are now back to the standard with excavation work and climate floor slab. Good luck with your project!

Hi David, brief update from us: unfortunately, we are no longer pursuing the idea of screw foundations / wooden floor slabs. Since we don't have an architect, I had to take care of everything myself, and important information was "overlooked" by me or I didn't ask in depth. We have received the structural engineering for the house – the concrete floor slab builders will calculate their own statics. This was also communicated to me by the house builder. Unfortunately, the carpenters see it differently, and having the statics recalculated would negate the possible financial advantage of screw foundations & wooden floor slabs. We are now back to the standard with earthworks and climate floor slab. Good luck with your project!

Hello Pascal,

As of today, we are sticking to it! The company that will most likely build our house had no concerns about the screw foundations, but as usual, they won’t install them themselves. The wooden floor slab will be made by them, and they will also calculate the statics. In the meantime, I have also found two companies that will install the screws (of course only after soil survey and static calculation). Currently, we are waiting for the result of a building pre-approval; unfortunately, the responsible office is not very fast. Since we have almost a 20% slope on the property, we would practically have to build with a basement using concrete. The first rough cost estimates show a price difference ranging from 80,000 to 130,000 Euros in favor of the screw foundations!

If it's only an 80 euro difference, I would stick with a concrete foundation.

Just kidding, that sounds extremely interesting for timber construction. When I last looked into it about half a year ago, I found some comments along the lines of "you need an exceptional structural analysis" or "it's not that easy to do in Germany at all." Was there no problem with this and the building authority and structural engineer just approved it?

Between slab/concrete foundation versus screw foundation/timber floor slab, I would now expect less of a cost advantage.

How can you imagine a basement as a hillside house standing on screw foundations? I would expect that it has to be buried on one side, then you still have to do some concreting, and a hybrid of concrete and screw foundations would cancel out all advantages again? Where does the cost advantage come from?