W
wetdec
Using an anhydrite screed is not a problem provided its treated correctly.
When the screed is dried out properly( to 0.5% moisture), remove any latency with a scraper, wire brushes or sanding then hoovering up all dust.
If you have a wet under floor heating system installed increase the temperature in incriments until full heat is reached then work backwards, this procedure helps in the drying process of the screed and aids curing.
When dust free use your adhesive maufacturer recomended sealer to seal the floor, this protects the screed and should be done in opposing directions to ensure coverage. It is important that guidence is saught from the adhesive manufacturer as the bond to screed is their territory.
Screeds move even after drying due to expansion and contraction especially when using wet under floor heating and can cause tiled surfaces to crack from latteral deflection. To combat this cracking an uncoupling membrane such as Ditra (1) or Dura-Ci membrane should be fixed before tiling.
Cut to size and laid using a flexible tile adhesive the membrane is easily tiled over. The membrane acts to protect the screed from moisture from above so should therefore be sealed properly. The channels in the membrane aid air movement over ufh and during adhesive drying.
(1)Please check Ditra for their fixing instructions
There are always questions re gypsum / anhydrite screeds, hope this goes some way to answering some of them.
.
When the screed is dried out properly( to 0.5% moisture), remove any latency with a scraper, wire brushes or sanding then hoovering up all dust.
If you have a wet under floor heating system installed increase the temperature in incriments until full heat is reached then work backwards, this procedure helps in the drying process of the screed and aids curing.
When dust free use your adhesive maufacturer recomended sealer to seal the floor, this protects the screed and should be done in opposing directions to ensure coverage. It is important that guidence is saught from the adhesive manufacturer as the bond to screed is their territory.
Screeds move even after drying due to expansion and contraction especially when using wet under floor heating and can cause tiled surfaces to crack from latteral deflection. To combat this cracking an uncoupling membrane such as Ditra (1) or Dura-Ci membrane should be fixed before tiling.
Cut to size and laid using a flexible tile adhesive the membrane is easily tiled over. The membrane acts to protect the screed from moisture from above so should therefore be sealed properly. The channels in the membrane aid air movement over ufh and during adhesive drying.
(1)Please check Ditra for their fixing instructions
There are always questions re gypsum / anhydrite screeds, hope this goes some way to answering some of them.
.
