As we now have a flow screed expert on here, I have a question. Lets say a screed has been laid to 50mm and is reading 90%Rh, latience has been removed. Which Dpms can be used ? The only one I have used is Uzin Pe404, but I have heard any can be used. True ?
There must be a lot because you have to have a surface membrane for any wet areas. Sent from my iPhone using Tapatalk
At 95% there are several systems I know of. Uzin do 2. P404 and I believe the other is p480, ardex do one called DPM 1c and a second called DPM 1CR, Norcos do one called Pro Gyp Base. There may be others. Possibly Forbo have one as I know they did some testing years ago in Holland. At 92% and 28 days old with no underfloor heating any DPM can be used on Gypsol Screeds. Other anhydrite screeds have to wait till 87% At 90% you can use directly bonded uncoupling systems like ditra for tiles, Express lay for vynil. I'm not aware of one if these for LVT. If you have underfloor heating the screed can be force dried. When done properly a 50mm Gypsol screed can achieve 75% in about 13 days. We also have Gypsol rapide screed now which dries naturally in about 14 days st 50mm. As with all drying times, depth and site conditions are important and for force drying the method is critical.
Its something I'd always recommend but it does depend on the covering. You might get away without a nembrane with sheet vynil in a wet area for example. It's a part of the specification that we dont generally get too involved in.
Could you not use a case hardener ? Then a dpm if readings are on the high side and times are tight ?
As with all drying times, depth and site conditions are important and for force drying the method is critical.[/QUOTE] And that is where it all falls to pieces whether it's commercial or domestic, you can spend hours discussing what's need to be done, yet customers seem to do the opposite or just shut the place up. You tell the customer vent and heat and they dry their washing in the room as it dries quicker You tell the site foreman that windows need to be left open but not when humidity is higher outside than inside and they shut everything on a lovely day and open it all when it's chucking it down.
What sort of case hardener are you thinking? Essentially the norcros and uzin fast track systems use a case hardener. Above 92% it's a sensible idea but not really necessary at 92 and below. That said it wouldnt harm either so I guess it would come down to cost and personal choice.
And that is where it all falls to pieces whether it's commercial or domestic, you can spend hours discussing what's need to be done, yet customers seem to do the opposite or just shut the place up. You tell the customer vent and heat and they dry their washing in the room as it dries quicker You tell the site foreman that windows need to be left open but not when humidity is higher outside than inside and they shut everything on a lovely day and open it all when it's chucking it down. [/QUOTE] Which is no different to any screed or concrete. Which is why DPMs are used so much.
We do silane case hardeners and dpm’s, all one coat fast systems, not cheap but high in RH and fast working times.
