ᐅ The screed is laid – should tiles be installed in the utility room due to the heat pump?
Created on: 21 Mar 2020 12:22
A
Andre77
Hey,
the screed has been in place for 1.5 weeks. If nothing changes, the heat pump is scheduled to be installed in week 15. Tiles should be installed under the heat pump as well. My site manager mentioned that you could lay tiles there using a vapor-permeable adhesive. What do you think?
And if so, should the tiling be done only in the area of the heat pump or also in the utility room and the adjacent storage room?
Thanks!
By the way, what tile sizes do you usually use in the utility room? Maybe some pictures as well?
the screed has been in place for 1.5 weeks. If nothing changes, the heat pump is scheduled to be installed in week 15. Tiles should be installed under the heat pump as well. My site manager mentioned that you could lay tiles there using a vapor-permeable adhesive. What do you think?
And if so, should the tiling be done only in the area of the heat pump or also in the utility room and the adjacent storage room?
Thanks!
By the way, what tile sizes do you usually use in the utility room? Maybe some pictures as well?
Thank you for the additional information!
The situation is that you want to install ceramic tiles as a rigid covering over a floating cement screed.
Screeds will certainly dry even without underfloor heating, but unless you are dealing with a special construction (these include all screeds not covered by standards, such as those with so-called accelerators or screed additives), the load-distributing layer cannot possibly have reached its equilibrium moisture content after about 2 weeks.
For special constructions, always follow the manufacturer’s instructions, but CAUTION: general statements like “ready for installation after 7 days” are misleading because only the construction conditions determine the drying process of a screed—and no manufacturer knows these conditions precisely!
The suggestion that using a “vapor-permeable adhesive” solves this issue is complete nonsense and indicates that the site manager does not understand the building physics involved or the relevant standards DIN 18365 (or even DIN 18356).
If you install too early, the screed slab will be prevented from relieving internal stresses caused by shrinkage during continued drying. This will inevitably lead to damage of the floor covering, which typically appears as random cracks in the rigid tile layer after about 1 to 1.5 years.
A responsible tiler will perform a CM (calcium carbide) moisture test and will not install tiles if the value exceeds 1.8 CM-%—not even partially or in isolated areas.
Regards, KlaRa
The situation is that you want to install ceramic tiles as a rigid covering over a floating cement screed.
Screeds will certainly dry even without underfloor heating, but unless you are dealing with a special construction (these include all screeds not covered by standards, such as those with so-called accelerators or screed additives), the load-distributing layer cannot possibly have reached its equilibrium moisture content after about 2 weeks.
For special constructions, always follow the manufacturer’s instructions, but CAUTION: general statements like “ready for installation after 7 days” are misleading because only the construction conditions determine the drying process of a screed—and no manufacturer knows these conditions precisely!
The suggestion that using a “vapor-permeable adhesive” solves this issue is complete nonsense and indicates that the site manager does not understand the building physics involved or the relevant standards DIN 18365 (or even DIN 18356).
If you install too early, the screed slab will be prevented from relieving internal stresses caused by shrinkage during continued drying. This will inevitably lead to damage of the floor covering, which typically appears as random cracks in the rigid tile layer after about 1 to 1.5 years.
A responsible tiler will perform a CM (calcium carbide) moisture test and will not install tiles if the value exceeds 1.8 CM-%—not even partially or in isolated areas.
Regards, KlaRa
Vicky Pedia22 Mar 2020 00:30Hello @KlaRa, that was explained clearly for us! But otherwise...
The decisive factor is actually the CM measurement; everything else won’t work, as explained in detail above!
The decisive factor is actually the CM measurement; everything else won’t work, as explained in detail above!
G
goalkeeper22 Mar 2020 01:27Our heat pump has been sitting directly on the screed since Wednesday. The drying program has been running since Friday.
And since the drying program can’t run without the heat pump, it’s just placed on the screed, and the tiler will lay tiles right up to the pump and then seal with silicone.
And since the drying program can’t run without the heat pump, it’s just placed on the screed, and the tiler will lay tiles right up to the pump and then seal with silicone.
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