Drying time 35 mm concrete slab before waterproofing?

[DesertCruiser]

I am going to embed underfloor heating pipes in an upstairs bathroom. I'm torn between embedding everything directly or doing it in two steps with concrete and levelling compound.

The advantage of embedding everything at once is the short drying time. The advantage of concrete plus levelling compound is the cost, and I can pour the concrete myself now and continue with other work in the bathroom, then hire someone to do the slope.

I have 16 mm pipes and will install 12 mm limestone flooring. According to LK, the pipes should have at least 30 mm of concrete cover for proper heat distribution. However, I'm including the limestone tiles in this, so I'm thinking of pouring 35 mm of concrete plus levelling compound for the slope.

Does anyone know how long it would need to dry before I can apply the levelling compound and install a waterproof membrane if I pour a 35 mm concrete cover on the existing concrete subfloor?

 

[myrstack]

If you buy a grout mix, you don't need to speculate about drying out and potential shrinkage because the bag specifies for such scenarios how long (typically a few days) you have to wait.

 

[jonaserik]

At normal room temperature with the door open, I would wait at least 14 days after the GV casting, as some moisture/wetness will seep into the underlying concrete and it may take some time to ascend. As for the sealing layer, it needs to be really dry for the layer to adhere properly, and to avoid trapping moisture/wetness that could cause the sealing layer to detach from the substrate.

 

[DesertCruiser]

At normal room temperature with the door open, I would wait at least 14 days after pouring GV, a certain amount of moisture/water will seep into the underlying concrete, and it can take some time to evaporate. As for the waterproof layer, it should be really dry for the layer to adhere, and to avoid trapping moisture/water which could cause the waterproof layer to detach from the substrate.

I probably won't be able to start any work with leveling compound and waterproofing until at least two months after casting, so it feels like I have some leeway then.

 

[atomlab]

How much is the total height above the floor drain? It quickly escalates in height if the bathroom is a bit larger and there needs to be a slope from the walls, etc.

 

[DesertCruiser]

How much is the total height above the floor drain? It quickly adds up in heights if the bathroom is a bit larger and there should be slopes out from walls, etc.

I will have a corner floor drain and plan to have a slope of 10 mm/m straight through the entire bathroom, so the highest point after self-leveling compound will be 30 mm above the floor drain level. Or did I misunderstand your question now?