Fully glue parquet on cement screed (new single-family house)

Hello everyone,

I am currently informing myself about the topic of gluing parquet and just can't get past a few questions..

The situation is as follows:
I have built a single-family house in timber frame construction and would like to glue parquet over the entire upper floor except the bathroom. It should be glued because we have underfloor heating and, moreover, impact sound should be minimized.

An accelerated cement screed has been installed, the heating-up program is already done, and the last CM measurement showed 1.5%, so the floor would now be ready for covering.

Now for the questions:
1. Does the screed need to be ground?

2. Do floor unevennesses need to be evened out? (According to DIN Schlagmichtot the specification is up to 3mm per 1m, I have unevenness of about 4mm in a few places)

3. Do the expansion joints built into the screed need to be closed or can you simply lay over them? They are only present at the doors in my case (with a flexible knife cutting every 15cm and inserting wave connectors and filling with resin would, I think, be a possibility)

I would be very happy about your experiences.

Regards

Svenson

It should be glued because we have underfloor heating and also because impact sound should be minimized.

Do you mean the impact sound going downstairs or the walking noise?
Gluing has its advantages as well as disadvantages; we currently have 200 sqm installed as a floating floor over underfloor heating without any problems. Surely measurements would show that glued flooring saves a few liters of gas, but for us, the unglued feels more homely because it’s not as hard.
I definitely don’t want to talk you out of it, since gluing is probably the most common method of installation. I just wanted to say that because of your reasons it doesn’t necessarily HAVE to be that way.

1. No, but it must be clean and preferably primed.
2. It's better, but it's up to you.
3. No, definitely do not close them. They are not there for nothing. With the size of your house, I don't see any problems with covering them.

Hello questioner.
Here are the answers to your questions (as far as they have not already been answered by other participants):

Now to the questions:
1. Does the screed need to be ground?
Answer: YES. This is a cleaning grind, which the floor or parquet fitter must already include in their offer (so no separate item. No one knows who previously "splotched" something on the screed surface. Therefore ALWAYS the cleaning grind.
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2. Do floor unevennesses need to be leveled? (According to DIN Schlagmichtot, the specification is up to 3mm per 1m, with unevenness of about 4mm in a few places at my place)
Answer: YES
The filler compound not only compensates for unevennesses exceeding the tolerance but – something a screed can never do – it ensures a uniformly absorbent surface to absorb moisture from the applied adhesive. Otherwise, there may be irregularities in the curing of the parquet adhesive.
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3. Must the expansion joints embedded in the screed be closed or can flooring simply be laid over them? They are only present at the doors in my case (cut flex every 15cm and insert wave connectors and pour with resin would probably be a possibility)
Answer: NO.
Since this is a heated screed, the joints between the rooms must be seen as MOVEMENT JOINTS and must remain functional.
They must not be closed in a force-locking manner. For a non-heated screed, this would be viewed differently (but only in residential construction).
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Regards and good luck: KlaRa