ᐅ Screed has been ordered, but rework is necessary.

Hello everyone,

I have little experience with screed myself, so a quick question for the experts.

I had screed installed in a 36sqm (387 sqft) extension. Concrete screed was used, and the surface is not completely smooth. Apparently, an additional smoothing layer is needed, which I would have to pay for separately.

In my opinion, when I order screed, it should be suitable to apply a floor covering of my choice directly on top without requiring any further work.

Who is right in this case?

Thank you

Post-processing of the screed is common because the flatness according to DIN 18202 is often insufficient for many types of flooring. If this is not ordered separately, it will be at your expense. The screed installer will only perform post-processing if the tolerances are not met.

bluetoothtony schrieb:

I had screed applied in a 36 sqm (390 sq ft) extension.
Concrete screed was used, and the surface is not 100% smooth.
Apparently, an additional smoothing layer is needed, which I have to pay for separately.

First of all: What exactly was ordered? Standard screed, flowing screed, power floated screed...?
And what do you mean by "not smooth"? Are there bumps, or is it simply not level?

bluetoothtony schrieb:

In my opinion, when I order screed, it should be ready for me to apply any floor covering of my choice on top.

No, that is not necessarily the case. It depends on what you order, and a certain tolerance is common.

Hello questioner,
As previous contributors have already explained: A screed is a load distribution layer, which in residential construction is always installed on top of an insulation layer.
Screed surfaces, even when properly executed, are generally not suitable for directly laying a floor covering on them—whether floating on an underlay or glued.
Exception: ceramic tiles (not large-format slabs) laid in a bedding mortar, after prior grinding, dust extraction, and priming.
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Unfortunately, you have a mistaken idea here, because applying a leveling compound (or, conversely, smoothing compound) is always the standard before installing floor coverings according to DIN 18365 and its commentaries!
Regards: KlaRa

Thanks for the comments, but the topic continues.

A precast screed based on concrete was used.

Now it is breaking off at every corner.
Underneath the screed, there is underfloor heating that was stapled onto a very flexible material.

As a result, when pressure is applied to the edge area, the entire corner breaks off.

It is difficult to determine the exact cause at the moment.

We had a problem with the underfloor heating, meaning the screed was not heated for over a week. However, it could also be due to the material.

It has now been decided that the screed will be completely removed and redone.
An anhydrite screed will be used this time.

This is probably a bit more expensive, but it should prevent further issues.
He will cover the labor costs, and I will pay for the materials.

1000€ for 36sqm (387 sqft)

I would like to hear your opinions.

Using anhydrite does not change the problem.