ᐅ Waterproof concrete + flush-mounted electrical boxes in the basement – how can this be addressed?
Created on: 13 Jun 2017 02:22
D
DReffects
Good evening,
We have commissioned a single-family house with a basement from a developer. Three of the four basement rooms will be used as living space or offices.
The basement exterior walls are made of 24cm (9.5 inches) thick waterproof concrete. From the beginning, it was clear to me that in a new build, electrical and network outlets should naturally be installed flush-mounted. Surface-mounted trunking is absolutely unacceptable to me, especially in living areas.
We have discussed this several times with the developer and were always told, “No problem, there have never been any issues with this.” Now, however, the electrician has raised concerns, and the developer is now siding with him.
So, my question to the community: What is the actual risk here? I thought that either the concrete is waterproof or it isn’t.
Are there any guidelines on how deep a flush-mounted box should be installed or other practical experience you can share?
Surface-mounted installation is, unfortunately, a huge no-go for me — which is exactly why we chose a new build, so that my office rooms don’t have to show something like that.
There are also decentralized ventilation units in the basement rooms that require electrical connections embedded in the concrete.
What options are available for this?
Thank you very much!
DR
We have commissioned a single-family house with a basement from a developer. Three of the four basement rooms will be used as living space or offices.
The basement exterior walls are made of 24cm (9.5 inches) thick waterproof concrete. From the beginning, it was clear to me that in a new build, electrical and network outlets should naturally be installed flush-mounted. Surface-mounted trunking is absolutely unacceptable to me, especially in living areas.
We have discussed this several times with the developer and were always told, “No problem, there have never been any issues with this.” Now, however, the electrician has raised concerns, and the developer is now siding with him.
So, my question to the community: What is the actual risk here? I thought that either the concrete is waterproof or it isn’t.
Are there any guidelines on how deep a flush-mounted box should be installed or other practical experience you can share?
Surface-mounted installation is, unfortunately, a huge no-go for me — which is exactly why we chose a new build, so that my office rooms don’t have to show something like that.
There are also decentralized ventilation units in the basement rooms that require electrical connections embedded in the concrete.
What options are available for this?
Thank you very much!
DR
DReffects schrieb:
Surface-mounted installation is unfortunately a major no-go for me – That’s precisely why we opted for a new build, so that my office spaces don’t have to show something like that. Especially in office spaces, I wouldn’t mind a well-executed surface-mounted wiring installation at all.
It actually contributes to the authentic office character.
Caspar2020 schrieb:
And this is precisely the minimum thickness needed to make the wall waterproof. With waterproof concrete (WU), the waterproofing depends on the material thickness. WU itself is waterproof but still vapor-permeable. Is there anything planned for the exterior? Considering living space usage and such?Thanks for the information regarding material thickness – are there any documents or DIN standards available on this?
What do you mean by exterior? The basement is insulated with perimeter insulation. These are expanded polystyrene boards, 12 cm thick (5 inches). How is that related to living space usage?
1) Electrical wiring inside the basement’s interior wallsI have already relocated it as much as possible, but for the main office room, this is only possible to a limited extent.2) Installation cavity on the exterior walls (this has the advantage of significantly improving the concrete’s appearance and comfort; but it should be planned by a professional because of the vapor permeability of the waterproof concrete mentioned above)That sounds very promising – comfort is always a plus. I’m not an expert in this area – isn’t a basement usually not very ‘comfortable’ otherwise? I assume the basement walls are normally plastered… Where can I find information on such installation cavities? It seems the concrete is supposed to “breathe,” right?
3) Construct thicker exterior wallsThat’s too late, we are currently starting the plumbing installation.Caspar2020 schrieb:
It depends. Depending on the manufacturing method and exposure class, at least 24 cm (9.5 inches) is recommended.
For example, with positive water pressure and cast-in-place concrete.Where can I find information about exposure classes and so on? Honestly, I don’t even know if we actually need a waterproof concrete basement at our site – the developer apparently just builds all houses that way out of principle, I was told.
AOLNCM schrieb:
@DReffects There are standard and deep flush-mounted boxes. For 1 to 2 cables, standard boxes can be used; with more cables and certain inserts, deep boxes are required. Don’t forget cable routing in or on concrete walls. If there is only one wall per room, you might consider mounting drywall (e.g., gypsum board) and installing the flush-mounted boxes there.Hmm, wouldn’t that rule out furniture mounting on that wall as well? The problem is also that a fan is installed in one of the exterior walls…
World-e schrieb:
It’s the same for me; I have no flush-mounted boxes in the waterproof concrete exterior walls. I planned as much electrical installation as possible in the masonry interior walls. However, one basement room will be made more comfortable; there, I will probably cover the exterior walls with Fermacell boards – there are types with a thin layer of polystyrene on them, which is sufficient for standard hollow wall boxes. There are also baseboard channels for cables, including compatible sockets, so everything looks integrated. In an office room, dado trunking makes sense in some areas where many sockets, LAN, etc., are needed and when some flexibility is required.Would the “breathability” of the waterproof concrete still be maintained with this?
You might have noticed I’m a layperson in this respect… which is why we decided on a turnkey build in the first place…
Our company has solved it this way!
- Wallpaper
- 14mm (0.55 inch) gypsum plasterboard
- 16mm (0.63 inch) chipboard
- 5cm (2 inch) aluminum rigid foam panels as insulation
- 24cm (9.5 inch) concrete
- 8cm (3 inch) insulation
- Exterior plaster/render
This way, the cables are hidden inside the wall.
- Wallpaper
- 14mm (0.55 inch) gypsum plasterboard
- 16mm (0.63 inch) chipboard
- 5cm (2 inch) aluminum rigid foam panels as insulation
- 24cm (9.5 inch) concrete
- 8cm (3 inch) insulation
- Exterior plaster/render
This way, the cables are hidden inside the wall.
Living "directly against the ground" is uncomfortable anyway.
I think it makes sense to build the interior walls out of masonry. That way, in the worst case, you end up with two concrete walls in the room, which cannot or should only be fitted with flush-mounted boxes using special methods (such as wall cladding).
I think it makes sense to build the interior walls out of masonry. That way, in the worst case, you end up with two concrete walls in the room, which cannot or should only be fitted with flush-mounted boxes using special methods (such as wall cladding).
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