Concrete floor without screed on the upper floor/attic, what to do?

Hello everyone,

in our house (newbuild, precast concrete) we only have screed on the ground floor. How should we best prepare the floor for the parquet then?

The neighbors mostly do primer + leveling compound. Then some kind of underlay as impact sound insulation and vinyl. So most of them have the floor laid floating.

But some parquet installers somehow had concerns and didn’t know how the whole thing should work without screed and said that without screed it would not be feasible in terms of sound insulation and residual moisture in the precast concrete elements..

As far as I understood correctly, the height from the floor to the door lintel is also not sufficient for screed. Maybe the doors have to be shortened.

How would you proceed? Would you still have screed laid (despite the high costs and effort with the doors)? Or is a leveling compound sufficient?

We would like to lay parquet everywhere. Do we have to consider anything if we don’t have screed downstairs?

Thanks in advance for your help!

We have it like this throughout the whole house, so only a concrete ceiling. Depending on what kind of flooring you want to install, you simply do a dry construction and there are several possibilities for that. In the bathroom, for example, we have a screed and above it Fermacell, then tiles on top. In the remaining area, we laid battens floating on the floor, between them Steico wood fiber insulation, and then screwed wooden planks on top. You can also screw OSB onto the battens in the same way and then lay your floor on top. Why should that be a problem? You don’t have to have doors shortened, how many cm of floor buildup is currently possible on the upper floor? What was the original plan and why is it now different?

We only have screed on the ground floor in our house (new build, ready concrete). How should we best prepare the floor for the parquet?

Who omitted the screed or did not inform the planner about the intended floors?

I usually only know the "problem" from developer townhouses that are deliberately built to meet the needs of statutory health insurance patients. A retrofit not only hits limits with the doors but also with the stairs. I recommend for middle houses to make peace with it and realize the fancy features only at the next level of the property ladder.

Hello " ". Parquet is a building material that has its peculiarities! It is indeed nice to look at, but it reacts like no other material to changes in indoor air humidity by swelling or shrinking. Every parquet! With concrete floors, it should be noted that they are usually equipped with a surface flatness that allows parquet installation (neither floating nor fully glued). So mechanical preparation is necessary here by shot blasting or grinding, then priming, and after that leveling with a self-leveling compound. Then we would have a flat (installation) substrate, but the moisture escaping slowly from the concrete due to its production drives into the room with the lowest moisture potential for at least 2-5 years. To keep it understandable: In the years following the new installation of the concrete, it will release its mixing water to the ambient air above. The parquet will absorb this and correspondingly expand or even deform. Therefore – my recommendation – you should abandon the idea of "direct installation." Tiles can certainly be glued directly onto a concrete substrate, but with parquet there is an incalculable risk of future floor damage due to warping! That is why every parquet layer should refuse this undertaking of laying parquet on concrete. The way via a floating screed is the safest and surely the damage-proof path. It also complies with the technical rules, which all rely on screed as an installation substrate. -------------- Regards: KlaRa

To keep it understandable: In the coming years after the new installation of the concrete, it will release its mixing water to the room air above.

This is the first time it occurs to me here, but doesn't concrete actually cure "without" drying out? The water is chemically bound into the structure of the concrete. Is the well-known construction moisture excess water beyond that?

It is the first time I notice this here, but doesn't concrete actually cure "without" drying? The water is chemically bound into the structure of the concrete. Is the known construction moisture still excess water beyond that?

Well, the answer to aspect 1 (doesn't concrete actually cure "without" drying) is no! If the concrete mixture were made only with the amount of water necessary for the chemical reaction, the "dry mortar" could not be processed at all. For this reason, excess water must be added (mixing water), which on the one hand chemically reacts with the cement and on the other hand must physically dry. For thicker industrial floors, which are usually at least 15 cm thick, the time to reach household moisture can take up to 12 years, especially when in contact with the ground. For thinner concrete slabs in residential construction, it still takes several years. It is correct that the known construction moisture is caused by (necessarily) excess water, but not only from concrete and screed, but also from drying excess water from wall masonry and wall plaster. ---------------- Regards: KlaRa