ᐅ Sealing of unplastered concrete surfaces

Dear forum, our shell construction is 90% complete, and we are currently wondering if we need to have the unfinished concrete ceiling on the ground floor (open kitchen, dining, and living area) sealed. The ceiling is intended to remain exposed for aesthetic reasons. Is there a risk that cooking grease will penetrate the ceiling over the years and leave unsightly stains?

And how do you handle the joints and edge finishes?
Ceiling spots, lamp outlets, LAN, ventilation… are all already hidden inside the ceiling?
No supply lines (water, sewage, heating…) in that area?
If the building envelope isn’t fully sealed yet, traces can still appear during rain.

There are several options.
- First, check if the quality allows it at all. Usually, this is not the case with standard concrete ceilings.
- Grinding
- Creating joints and wall edges
- Sealing with water glass is the most affordable option. However, only use potassium or lithium-based water glass.

Sealing is highly recommended, not only to keep dirt away but also to prevent the concrete from dusting.

Hendrik1980 schrieb:

Is there a risk that kitchen grease will gradually penetrate the ceiling over the years and leave unsightly stains?

Stains from kitchen grease, fireplaces, candles, and similar sources will eventually become visible. If this bothers you, sealing the surface makes cleaning easier.
When the ceiling is dusted yearly to remove cobwebs and dust, less concrete dust falls down.
The appearance, with or without joints, is a matter of personal preference.
I know apartments in Berlin Marzahn where tenants have bare concrete walls and ceilings and are very happy with them, including all the joints and patchwork.

But then they are tenants and not single-family house owners 😉 I think the expectations are different. Of course, much less would be sufficient. Paint on the wall is also (almost) just aesthetics...

We want to keep the concrete ceiling in the open hallway-living room-kitchen area on the ground floor as it is. I would leave the joints open because I am not sure the result will look good if the joints stand out in color from the concrete. I imagine it will look more harmonious with open joints. The plan is simply to clean the ceiling roughly and keep it in a natural look with its imperfections.

What does "Sealing with water glass is the most cost-effective. But only use potassium or lithium." mean? Are you referring to mineral water from glass bottles?

Are there any other tips to consider? Maybe inform the plasterer and the contractors working on the concrete ceiling that you want a fair-faced concrete ceiling and that some caution is necessary.

No, I mean potassium or lithium water glass.
This silicifies the surface of the concrete.

Informing the trades might help, but not with general contractor projects involving sub-subcontractors.
You want to see the defects, but this has nothing to do with fair-faced concrete; it’s simply unfinished structural work.
Your questions suggest you haven’t dealt with this much yet.

Think carefully about whether you’re just following a trend and if this really fits harmoniously into your concept. Especially executed like this…

What measures are you taking regarding soundproofing? Will you have carpets and acoustic absorbers...?
Are there any pipes or conduits running anywhere? Or do you want those exposed as well?
This style is more suited for an industrial loft rather than a “small” combined living-dining-kitchen area. Especially with a standard ceiling height.
I don’t want to discourage you, but please reconsider and answer my points.