ᐅ Concrete Slab - What to Check Before Pouring?

Created on: 16 Apr 2019 07:35
Q
quisel
Q
quisel
16 Apr 2019 07:35
Hello everyone,

We are now slowly but surely approaching the end of the demolition/excavation phase and preparing the base slab. A few days ago, I read a post here about incorrectly installed pipes, and I would like to avoid such embedded issues in concrete.

My question is whether there are general tips on what to watch out for before pouring the base slab. Logically, this mainly concerns everything installed beneath or within the slab. So far, my list includes:
  • Correct spacing/dimensions for waste pipes
  • Proper installation of the ring earth conductor, connection tabs for equipotential bonding, and external lightning protection
Of course, the ring earth conductor must be checked before the slab is poured since it lies beneath the blinding layer. That’s about all I have on my list so far, which is obviously quite short. Are there additional aspects to consider?

Does it make sense to ask the structural builder to schedule a “inspection meeting” with the architect, lightning protection company, and plumbing contractor before the concrete is poured to prevent any potential problems?

Thanks in advance and best regards!
Knöpfchen16 Apr 2019 08:02
The reinforcement in the concrete slab itself must be connected to the foundation earth electrode at intervals of 2m (6.6 feet) for equipotential bonding.
This work should only be carried out by an electrician or directly under their supervision.
The foundation earth electrode must be handled the same way.
Everything must be documented with photos and forms. Very important!!!!!
seth048716 Apr 2019 08:44
We received a report from the electrician regarding the foundation grounding system. They performed some measurements there.

The installation of the drainage pipes was handled by the plumbing company. What exactly am I supposed to check? I’m not going to monitor every single step the tradespeople take. At first, I would trust that they are doing the work correctly. It might make sense to check the position of the pipes after the slab has been poured. If there is time, even earlier. But usually, everything happens very quickly one after the other. I wouldn’t have had an opportunity to check it in between.

It would be unfortunate if a mistake were made there, but how often does that actually happen?

If you take this approach to the extreme, you would have to continuously verify all the dimensions of walls and installation lines throughout the construction.

It’s better to have an independent inspector review the house at key stages of construction.

And whenever you’re on site, walk through the house with a watchful eye and, if necessary, a tape measure, and take a careful look around.
Q
quisel
16 Apr 2019 10:03
Thank you both for the feedback; it has already helped me a lot!
seth0487 schrieb:
What exactly do I need to check? I’m not going to monitor every single step the workers take.

Certainly not every step, but in my view, there are key milestones where it’s worth taking a closer look. For me, that’s definitely before irreversible work is done on the concrete slab.
seth0487 schrieb:
If you take this approach further, you’d have to continuously check all wall dimensions and installation lines during construction.

I see it as a given that I regularly check together with the architect throughout the build to make sure everything fits. The frequency and level of detail for these checks depend, in my opinion, on the working style of each trade.

For installations in sand-lime brick or drywall partitions, I generally consider this less critical than for installations embedded in concrete.
seth0487 schrieb:
Just have an independent inspector go through the house at certain construction stages, and that’s enough.

That’s not planned at the moment, but I will think about it again!
seth0487 schrieb:
And whenever you’re on site, walk through the house with a watchful eye and, if needed, a tape measure to carefully check everything.

That was already planned – and that’s exactly why I was hoping for tips regarding typical weak spots.
B
Bookstar
16 Apr 2019 10:07
There are two possibilities. You have a good shell builder, and you need to do little inspection because everything is running smoothly. Or you have a poor shell builder, and no amount of supervision will help.
Q
quisel
16 Apr 2019 10:19
Bookstar schrieb:
There are two possibilities. You have a good shell contractor and need little supervision—it just works. Or you have a bad shell contractor, and no amount of supervision will help.

Based on feedback from acquaintances and tradespeople I know: the first option.
Of course, that’s no guarantee the construction will go the same way— but I think we’ll be fine with our shell contractor. Things do tend to get forgotten sometimes, whether intentionally or not. I don’t want to assume any bad intent.

But hey, just for my own peace of mind and conscience, I like to keep an eye on things from time to time. I can always be upset later— but at least then I won’t be able to blame myself for not visiting the site more often.