ᐅ Installing tiles with PCI adhesive on screed that is three weeks old
Created on: 11 Dec 2017 13:37
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stefanc84S
stefanc8411 Dec 2017 13:37Hello,
Our construction company wants to install the screed (cement, not self-leveling) just before Christmas. The heating will only be turned on about three weeks later due to the holiday period.
=> Fourteen days of drying followed by a heating-up phase is generally recommended. Do you see any problem with those three weeks without heating?
Shortly before the heating is put into operation, the technical room is supposed to be tiled. This would be done by a tile installer hired separately by us, and they plan to use PCI adhesive because the screed will still not be dry.
=> Elsewhere I have read that PCI adhesive should only be used within the first five days, meaning only on very fresh screed. Ours will already be almost three weeks old by then. How do you assess this? Could this cause poor workmanship?
The construction company is taking a relaxed approach to this, as they don’t have to guarantee the tiles since our tile installer is responsible.
Lastly, a question about the reason why tiling is planned beforehand.
The multi-utility installation will be completed/sealed shortly afterward. It is supposed to be installed ON the tiles (on the floor).
=> Why? Why can’t you simply wait until everything is dry and then tile around the floor entry point from the outside?
I find all of this somewhat strange and have the feeling it is only being done this way because it fits well into the construction company’s schedule...
Our construction company wants to install the screed (cement, not self-leveling) just before Christmas. The heating will only be turned on about three weeks later due to the holiday period.
=> Fourteen days of drying followed by a heating-up phase is generally recommended. Do you see any problem with those three weeks without heating?
Shortly before the heating is put into operation, the technical room is supposed to be tiled. This would be done by a tile installer hired separately by us, and they plan to use PCI adhesive because the screed will still not be dry.
=> Elsewhere I have read that PCI adhesive should only be used within the first five days, meaning only on very fresh screed. Ours will already be almost three weeks old by then. How do you assess this? Could this cause poor workmanship?
The construction company is taking a relaxed approach to this, as they don’t have to guarantee the tiles since our tile installer is responsible.
Lastly, a question about the reason why tiling is planned beforehand.
The multi-utility installation will be completed/sealed shortly afterward. It is supposed to be installed ON the tiles (on the floor).
=> Why? Why can’t you simply wait until everything is dry and then tile around the floor entry point from the outside?
I find all of this somewhat strange and have the feeling it is only being done this way because it fits well into the construction company’s schedule...
Three weeks unheated is acceptable, ideally keeping the house above 0°C (32°F) with a small electric heater.
There are many PCI adhesives available; your tiler probably means the very expensive flexible S2 type, which is specifically designed for this situation. However, with a conventional screed, there is relatively little water in the house anyway.
Still, I would only have the part of the room tiled that is absolutely necessary. Water passes through the grout very slowly, so any remaining unbound moisture in the screed will disappear gradually. I did something similar with my full-surface waterproofing under the buffer tank. I only completed 1m² (11 sq ft) and finished the rest of the room after functional and final drying heating.
There are many PCI adhesives available; your tiler probably means the very expensive flexible S2 type, which is specifically designed for this situation. However, with a conventional screed, there is relatively little water in the house anyway.
Still, I would only have the part of the room tiled that is absolutely necessary. Water passes through the grout very slowly, so any remaining unbound moisture in the screed will disappear gradually. I did something similar with my full-surface waterproofing under the buffer tank. I only completed 1m² (11 sq ft) and finished the rest of the room after functional and final drying heating.
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stefanc8411 Dec 2017 20:42Thank you for the reassuring information!
The only remaining question is whether this special solution is truly necessary just because of the introduction of multiple utility lines. Are tiles really needed under the 2cm (1 inch) "overhanging edge"? It wouldn’t bother me at all if this "joint" is filled with grout.
The only remaining question is whether this special solution is truly necessary just because of the introduction of multiple utility lines. Are tiles really needed under the 2cm (1 inch) "overhanging edge"? It wouldn’t bother me at all if this "joint" is filled with grout.
Whether this is necessary for the multi-utility setup is hard to say from a distance. However, if equipment is to be installed in the utility room, it’s definitely better to have tiles underneath. I decided against that and instead used standard DN 110 (4-inch) PVC pipes from below, ran the cables through, then sealed everything with expanding foam and screed before tiling over it.
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stefanc8412 Dec 2017 01:25No technical equipment will be installed separately; everything is mounted on the wall. It depends on the utility provider; ours only accepts multi-utility entries, no underground conduits.
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