Hello professionals!
I need the help of this great forum once again.
We are about to install the screed in our house construction. Since we are somewhat behind schedule, our architect mentioned a fast-drying or quick-hardening screed. The downside is that it costs about 1000 euros more and might lead to losing warranty claims.
If we decide to go for it and finish the construction about a month earlier, it would at least make financial sense—one month less rent now, etc.
However, we are a bit concerned about possibly giving up warranty rights. Does anyone have experience and can confirm if this is true?
Also, are there any other disadvantages of fast-drying screed that we should be aware of?
Thanks a lot and have a nice evening!
Schubbiano
I need the help of this great forum once again.
We are about to install the screed in our house construction. Since we are somewhat behind schedule, our architect mentioned a fast-drying or quick-hardening screed. The downside is that it costs about 1000 euros more and might lead to losing warranty claims.
If we decide to go for it and finish the construction about a month earlier, it would at least make financial sense—one month less rent now, etc.
However, we are a bit concerned about possibly giving up warranty rights. Does anyone have experience and can confirm if this is true?
Also, are there any other disadvantages of fast-drying screed that we should be aware of?
Thanks a lot and have a nice evening!
Schubbiano
Hello "Schubbiano",
At least for cement screeds, drying to the point where the surface can be covered typically takes about 6 weeks under good drying (meaning on-site) conditions. Calcium sulfate screeds dry faster; you can usually expect surface readiness within about 14 days.
Additional costs: marginal.
Nowadays, so-called drying accelerators, that is screed additives, have become state-of-the-art.
Advantage: faster surface readiness.
Disadvantage(s): some accelerators work well, others not as effectively as expected, and furthermore, all of these are special constructions not covered by the screed standards (I will refrain from listing all of them here)!
This means the client must be thoroughly informed and give consent before installation!
The warranty—as already stated on this topic—is, of course, provided and assumed by the screed installer. The installer MUST also pass on the following information to the client:
a) the method by which the residual moisture will be determined,
b) how the measurement will be carried out, and
c) from which measured value surface readiness for which type of floor covering can be assumed.
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If the extra costs are said to be 1,000€ (€1,000), I would definitely double-check this directly with the offeror, looking them firmly in the eyes.
Depending on the floor area, it might be that a rapid-hardening cement is being planned. These cement types are always significantly more expensive than normal cement but also fall under “special screeds” (meaning the client must be advised and give consent).
The screed additives mentioned earlier are only added in proportion to the cement and as a replacement for mixing water during the mechanical mixing of the screed mortar. The additional costs for these additives are also not significant, as they are relatively low. We would never arrive at €1,000 in extra costs from this alone.
------------
Best regards and good luck: KlaRa
At least for cement screeds, drying to the point where the surface can be covered typically takes about 6 weeks under good drying (meaning on-site) conditions. Calcium sulfate screeds dry faster; you can usually expect surface readiness within about 14 days.
Additional costs: marginal.
Nowadays, so-called drying accelerators, that is screed additives, have become state-of-the-art.
Advantage: faster surface readiness.
Disadvantage(s): some accelerators work well, others not as effectively as expected, and furthermore, all of these are special constructions not covered by the screed standards (I will refrain from listing all of them here)!
This means the client must be thoroughly informed and give consent before installation!
The warranty—as already stated on this topic—is, of course, provided and assumed by the screed installer. The installer MUST also pass on the following information to the client:
a) the method by which the residual moisture will be determined,
b) how the measurement will be carried out, and
c) from which measured value surface readiness for which type of floor covering can be assumed.
---------------
If the extra costs are said to be 1,000€ (€1,000), I would definitely double-check this directly with the offeror, looking them firmly in the eyes.
Depending on the floor area, it might be that a rapid-hardening cement is being planned. These cement types are always significantly more expensive than normal cement but also fall under “special screeds” (meaning the client must be advised and give consent).
The screed additives mentioned earlier are only added in proportion to the cement and as a replacement for mixing water during the mechanical mixing of the screed mortar. The additional costs for these additives are also not significant, as they are relatively low. We would never arrive at €1,000 in extra costs from this alone.
------------
Best regards and good luck: KlaRa
S
Schubbiano17 Jan 2021 17:55Thank you all for your detailed and very thorough feedback. It is very helpful. Great forum! 🙂
We are also behind schedule and the construction contract specifies cement screed. The general contractor suggested that to save time, we could also use calcium sulfate screed. There is no additional cost. I have read that this type of screed should not be installed in damp rooms, such as bathrooms, basements, etc. The problem is that once it absorbs moisture, it will deteriorate (turns into gypsum). Does anyone have experience with this, or am I worrying unnecessarily?
N
nordanney23 Jan 2021 20:27Miwi2009 schrieb:
I read that this type of screed should not be installed in damp rooms,It is possible, but in that case, proper sealing of the entire floor becomes even more important.Miwi2009 schrieb:
We are also behind schedule and our construction contract specifies cement screed. The general contractor now suggested that to save time, we could use calcium sulfate screed instead.
There is no additional charge.
I have read that this type of screed should not be installed in wet rooms such as bathrooms, basements, etc. The problem is that once it absorbs moisture, it will be damaged (turns into gypsum).
Does anyone have experience with this, or am I worrying unnecessarily? Answer:
In general, we don’t have wet rooms in the living areas.
As "nordanney" mentioned, in bathrooms (and not only for calcium sulfate screeds), a surface waterproofing membrane is advisable depending on the water exposure.
In basements, if there is only a slab directly on the ground—which is not sealed on the backside—and NO screed over insulation, a waterproofing membrane should be installed before laying the screed.
It should also be considered that thermal insulation must be added if the basement is going to be converted from a secondary use to living space.
In most cases, this will fail due to the available ceiling height, since approximately 10cm (4 inches) of insulation is needed, plus a screed thickness of around 35mm to 45mm (1.4 inches to 1.8 inches), depending on the binder and material strength (better: flexural tensile strength).
What needs to be considered for calcium sulfate screeds and floor-level shower trays is the following: either a modelled area with cement screed must be made (which hardly anyone does), or a factory-made plastic shower tray is used instead. The remaining floor area can then be sealed with an alternative liquid-applied waterproofing.
Best regards and good luck, KlaRa
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