D
DHTiling
Here are some guidelines that PCI have allowed me to type up for all you PCI users who need a method statement for tiling to anhydrite screeds...
Tiling to Anhydrite screeds by PCI.
Anhydrite screeds are now becoming more and more apparent in the market place,and as direct result of this PCI construction systems are being asked to specify products for this type of finish.
The following is issued as a guidline :
It is important that the screed has been laid as per the latest manufacturer's data sheet,paying particular attention to:
1. Underfloor heating
2. Residual moisture conten
3. Flor finishes-surface preperation.
1.
Anhydrite screeds are suited for underfloor heating since they are laid much thinner than traditional screeds, and therefore eliminate air pockets and voids around heating pipes etc....
In heated calcium sulphate floors,movement joints should be carried through both the screed and the tile bed dividing the tiling into area's no greater then 40m2, or in accordance with the sceed manufacturers instructions....
The area bounded by the movement joints should be square to rectangular with the width to length ratio not exceeding 5 to 8 mtrs.....
2.
Residual moisture content of 0.5% or less must be obtained before the application of primer G, drying times of the screed is normally approximatley 1mm per day uoto 40mm and 0.5mm per day thereafter at 20c,65-70 relative humidity.
To reach this figure of 0.5% witht he use of underfloor heating, it should be borne in mind that this will increase the humidity of the site.
It is therefore essential that good ventilation be maintained during this period of drying.
3.
If underfloor heating is being used- turn off 48 hrs prior to the following applications..and commissioning of the heating.
Ensure that the surface of the screed is free of any dirt,dust,oil,grease or any other contamination likely to prevent a good bonding surface.
The finished surface should be abraded/sanded then cleaned with a vacuum cleaner if laitence is present.
Apply primer G, diluted 1:1 with water to the whole area, ensuring a continous coat of the primer without the formation of puddles.
When dry a second coat must be applied NEAT as above.
Primer G is coloured blue to facilitate this application.
When the primer is dry then tiling can be carried out with the appropiate PCI adhesive to suit .
If underfloor heating is integrated in the system th en this must be left off for a further 48 hrs after completion of the grouting and then gradually increase the heat over the next 7 days.
This will reduce the possibility of any thermal shock being appied to the over all system..
2. Residual moisture conten
3. Flor finishes-surface preperation.
1.
Anhydrite screeds are suited for underfloor heating since they are laid much thinner than traditional screeds, and therefore eliminate air pockets and voids around heating pipes etc....
In heated calcium sulphate floors,movement joints should be carried through both the screed and the tile bed dividing the tiling into area's no greater then 40m2, or in accordance with the sceed manufacturers instructions....
The area bounded by the movement joints should be square to rectangular with the width to length ratio not exceeding 5 to 8 mtrs.....
2.
Residual moisture content of 0.5% or less must be obtained before the application of primer G, drying times of the screed is normally approximatley 1mm per day uoto 40mm and 0.5mm per day thereafter at 20c,65-70 relative humidity.
To reach this figure of 0.5% witht he use of underfloor heating, it should be borne in mind that this will increase the humidity of the site.
It is therefore essential that good ventilation be maintained during this period of drying.
3.
If underfloor heating is being used- turn off 48 hrs prior to the following applications..and commissioning of the heating.
Ensure that the surface of the screed is free of any dirt,dust,oil,grease or any other contamination likely to prevent a good bonding surface.
The finished surface should be abraded/sanded then cleaned with a vacuum cleaner if laitence is present.
Apply primer G, diluted 1:1 with water to the whole area, ensuring a continous coat of the primer without the formation of puddles.
When dry a second coat must be applied NEAT as above.
Primer G is coloured blue to facilitate this application.
When the primer is dry then tiling can be carried out with the appropiate PCI adhesive to suit .
If underfloor heating is integrated in the system th en this must be left off for a further 48 hrs after completion of the grouting and then gradually increase the heat over the next 7 days.
This will reduce the possibility of any thermal shock being appied to the over all system..
