ᐅ Is it advisable to have the foundation slab inspected by a building surveyor?

Hello everyone,

In mid-December, the foundation slab for our single-family house was poured. The civil engineering company is a family-run business from the region with an excellent reputation. The preparations went very smoothly (they even started with the earthworks before we had signed the contract), and we didn’t have to worry about anything (they also handled various inquiries with the local authorities since they already knew each other).

On the day the foundation slab was poured, unfortunately, we were all very sick (middle ear infection with a fever just under 40°C (104°F)) and couldn’t visit the site (just getting to the bathroom was already a struggle). I went there the next day for a quick look. The slab was completely covered, which we expected because there had been heavy snowfall at the time and nighttime temperatures dropped to -12°C (10°F). The civil engineering company regularly works under such conditions; at our previous landlord’s site, they poured the slab on Christmas Eve despite heavy snow.

So far, so good. However, when we visited the site about a week later (we don’t live locally), some parts of the protective foil were missing. We suspect that children playing may have removed it because the wind alone shouldn’t have been able to do that—the foil was very well secured.

Now we don’t know exactly when this happened, so we’re unsure if the slab was already frost-resistant at that time, and we’re wondering if this might have had any negative effects. Visually everything looks fine and, for example, I haven’t noticed any cracks. The slab will be inspected in spring by our construction manager, but I assume they will mainly check if all measurements are correct.

Therefore, I wanted to ask here if you would recommend having the slab inspected by an independent expert. I’ve heard that organizations like TÜV Süd offer such services. Or is that money wasted because they would basically just measure again and check for cracks (as I said, I couldn’t see any; everything looked fine to me, but I am a complete layperson)?

Thank you very much in advance for your help!

Basically, it would have been more sensible to carry out an inspection before pouring the concrete slab. Only then can the inspector check whether enough reinforcement steel has been used, as the general contractor often tries to cut corners here. The topic of "pouring the concrete slab in freezing conditions" was discussed recently in this forum. Just use the search function.

Maybe I used the term general contractor (GC) incorrectly. We are building with a prefabricated house supplier, but they are not responsible for the foundation slab. We arranged the excavation and groundwork ourselves through the civil engineering company. So I have absolutely no concerns about them using too little steel or anything like that. This may be naive, but they have an excellent reputation in this region, and we have heard only positive feedback from everyone who has worked with them. My main concern is whether an inspector could still identify any potential damage caused by the cold temperatures after the fact.

Who carried out the grounding? A qualified professional? Is it properly documented for the electrician installing your electrical connection?
It would have been better to have an inspector involved before pouring the foundation slab.

Since the site manager approves your work before the house is installed, it’s possible that they will point out any defects if there are any. That doesn’t bother them—in fact, quite the opposite. If they place their house on a faulty foundation slab and problems arise later, they are the ones responsible in the end... because they are the professional and should have identified the issues.

If I remember correctly, there are also certain safety factors in structural engineering. No structural engineer designs a foundation to just barely work, assuming the contractor will follow everything perfectly. They’re not exactly clueless.

The same goes for the foundation earthing. This isn’t a big issue in a TN-C-S system, but it would be problematic in a TT system.

hanse987 schrieb:

Who installed the grounding? A qualified professional? Is it properly documented for the electrician who will handle your electrical connection?
It would have been better to have an inspector check before pouring the foundation slab.

The grounding was done by the civil engineering company. Our site manager was also present and went through everything with the civil engineering team. Since both our prefabricated house supplier and the civil engineering company are local, they work together regularly.

I appreciate any advice, but tips like “it would have been better to do this earlier” don’t help me at all. As I mentioned, the civil engineering company regularly works in snow and cold conditions, and we have only heard positive feedback from friends and acquaintances who poured their foundation slabs under similar circumstances. So, I am not questioning whether the civil engineering company did everything correctly. My concern is whether removing the protective foil too early might have caused frost damage, and whether an inspector could identify this retrospectively.