ᐅ Finishing strip and sealing between garage and cement screed

Hello everyone,

On Monday, cement screed was installed in the garage. Unfortunately, the screed installer did not fit an edge trim beforehand. I will, of course, clarify with the general contractor why this was not done. However, if this is excluded by the builder, I would like to gather information on how to properly seal everything and achieve a clean finish for the tiles. I still have some leftover bitumen waterproofing membranes. Could I use them to seal the gap between the screed and the base slab? Then place a metal angle on top that slightly overlaps the screed? Does anyone have any ideas?

Hello questioner,
Your question cannot be answered solely by the digital system; it really depends on the local situation.
Let’s start with the simpler point, the edge trim.
From what I can see in the photos, a cement screed was installed on a separating layer above a floor slab.
An edge profile should definitely be installed, at least for edge protection (e.g., from vehicle traffic).
However, this can be added later quite easily, for example with a stainless steel profile, especially since the tile height also needs to be taken into account and the exterior area must be raised to the level of the screed surface.
According to DIN 18534, the garage floor (screed) must only be sealed if there are living spaces below the garage area.
If this is not the case, the screed surface should still be protected. In this case, tiles are planned, which can be installed together with a flexible waterproofing slurry according to planning guidelines.
Other methods, such as using leftover bitumen waterproofing membranes, are not very effective and are also not necessary for the proper construction.
However, the critical question concerns the screed edges. The screed was probably installed without a slope (which would be unusual). This means that any dripping water (from vehicles after rain or snow) must not penetrate in the wheel area.
In the simplest case, the joint gap can be sealed with an elastic sealant before installing the baseboard.
Although this is not true "waterproofing," it will serve its purpose permanently in the secondary space (the garage) when covered with base tiles and filled joints.
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Good luck: KlaRa

Hello KlaRa,

Thanks for your feedback. My main concern is whether it is problematic if moisture gets between the separation layer and the screed. I wanted to cover/seal this "gap" if necessary. There is nothing left under the garage. I will definitely install a stainless steel profile as well.

The screed slopes down by 2cm (1 inch). It’s not much, but it should be enough. The edge areas will be tiled with baseboards and then properly sealed.

The main issue was the baseboard and the sealing between the screed and the separation layer.

What would a suitable baseboard look like, and how would it be fixed?

(...) Moisture can get between the separation layer and the screed. I wanted to cover or close this "gap" if necessary.
Answer
That is not necessary, especially since a drainage channel still needs to be installed across the driveway in front of the garage (prevents rainwater from flowing into the garage).
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"What could a suitable strip look like, and how should it be fastened?"
Answer
This is primarily the responsibility of the tile setter. Either they purchase an appropriate profile from profile manufacturers (this is the usual approach) or a stainless steel L-profile must be custom-made. Depending on the material thickness, it is either doweled into the concrete slab and incorporated into the adhesive bed of the tile surface, or (as is not uncommon in industrial settings) the screed edge is milled stepwise to match the material thickness (or notched with parallel cuts), then the profile is screwed in and additionally embedded in an epoxy resin bed (this secures it to the screed in addition to the screws).
But water does not affect cement screed at all!
Therefore, the front screed edge does not need to be “sealed.”
Best of luck: KlaRa

Ok. Thanks for the feedback. Now I know what to do.