Hello everyone,
I had originally planned to use cement screed, but my tiler told me: with liquid screed, you don’t need movement joints for the tiles, and for the parquet flooring, you don’t need leveling compound.
Ground floor: tiles
Upper floor: parquet, main bathroom with tiles
My screed installer offers both options.
Should I still stick with cement screed?
I would like to hear your opinions on this.
I had originally planned to use cement screed, but my tiler told me: with liquid screed, you don’t need movement joints for the tiles, and for the parquet flooring, you don’t need leveling compound.
Ground floor: tiles
Upper floor: parquet, main bathroom with tiles
My screed installer offers both options.
Should I still stick with cement screed?
I would like to hear your opinions on this.
Hello "tumaa".
You shouldn’t fall into the impression that you have landed in a "confusing forum" here.
Here is a professional opinion on your topic:
As long as you do not plan to install a barrier-free shower in the bathroom, and at least the shower tray is not made from a prefabricated (therefore watertight) system component, you can use a cement screed, a conventional calcium sulfate screed (CA), or a calcium sulfate flowing screed (CAF) throughout the entire living area (including the bathroom)!
Between different living spaces, with cement screeds and conventionally installed CA screeds, a movement joint must be formed (this goes completely through the screed down to the insulation layer). For flowing screeds, it depends on the geometry of the room. A movement joint is also required for heated screeds!
The cost difference between cement and CAF flowing screeds is almost negligible, as the latter can be applied in somewhat thinner layers (which reduces costs).
What should not be done in a residential building is to combine cement screed and CAF. This is simply due to the increased effort required by the screed installer since both screed types require different mixing and pumping technology.
Please quickly forget the idea that CA or CAF screeds do not need to be skim-coated, as that is technically incorrect!
This is not (only) about surface evenness, but also about the uniform absorbency relevant for adhesive bonding of floor coverings. Although CAF screed levels itself, it must be immediately "troweled" after application – and the trowel marks would be instantly visible in reflected light under an adhered elastic floor covering!
As you can see, this topic is not so simple as to be safely answered with a brief “in-between” reply.
Regards, KlaRa
You shouldn’t fall into the impression that you have landed in a "confusing forum" here.
Here is a professional opinion on your topic:
As long as you do not plan to install a barrier-free shower in the bathroom, and at least the shower tray is not made from a prefabricated (therefore watertight) system component, you can use a cement screed, a conventional calcium sulfate screed (CA), or a calcium sulfate flowing screed (CAF) throughout the entire living area (including the bathroom)!
Between different living spaces, with cement screeds and conventionally installed CA screeds, a movement joint must be formed (this goes completely through the screed down to the insulation layer). For flowing screeds, it depends on the geometry of the room. A movement joint is also required for heated screeds!
The cost difference between cement and CAF flowing screeds is almost negligible, as the latter can be applied in somewhat thinner layers (which reduces costs).
What should not be done in a residential building is to combine cement screed and CAF. This is simply due to the increased effort required by the screed installer since both screed types require different mixing and pumping technology.
Please quickly forget the idea that CA or CAF screeds do not need to be skim-coated, as that is technically incorrect!
This is not (only) about surface evenness, but also about the uniform absorbency relevant for adhesive bonding of floor coverings. Although CAF screed levels itself, it must be immediately "troweled" after application – and the trowel marks would be instantly visible in reflected light under an adhered elastic floor covering!
As you can see, this topic is not so simple as to be safely answered with a brief “in-between” reply.
Regards, KlaRa
D
Daniel-Sp19 Aug 2020 10:40toboter schrieb:
The installer was recommended to us by several other trades as a good screed layer. So far, the contact has also been quite positive. Whether he can really install the cement screed that well will probably only become clear afterward... But it seems that the cement screed is sufficient and suitable for underfloor heating with a heat pump, so we will probably go with that. We have cement screed everywhere. It was applied cleanly; no leveling compound was necessary. In the living room, solid wood planks were glued down—so not an ideal flooring for underfloor heating. The supply temperature from the heat pump has not exceeded 25°C (77°F), with room temperatures between 22.5–23°C (72.5–73.4°F). I don’t see how anhydrite screed would perform noticeably better under these conditions.
Bookstar schrieb:
It is indeed possible to mix cement and anhydrite in a single-family house. However, the drawback is that you need to dry-heat twice using different methods. I would not do it anymore. Always use cement throughout, and that’s that. Please always read the answers carefully!
In my response, I wrote:
"What you should not do in a residential building: combine cement screed and CAF. This is simply due to the additional effort required by the screed installer, as both screed types need different mixing and pumping techniques."
My text clearly does NOT imply that these binder types cannot be combined in principle.
Smaller screed companies usually specialize either in cement or calcium sulfate. Larger companies can afford to maintain both necessary installation (pumping) methods.
But just as it is uneconomical for an asphalt screed company to work on an area of only 10 m² (about 108 square feet), it is economically unfavorable for the builder to bear the naturally higher incidental costs of combining cement and CAF binders.
However, I believe the builder "tumaa" already understood my previous objection correctly!