We fitted a whole block on Pe404, PE280, 151 then Marmoleum. That was almost 2 years ago now. Never had any issues.
Not sure what your role is merit. You are not sure about vynil or wood being fast tracked. I say with total confidence that fast track systems are perfectly fine with tiles, wood, vynil andcany other flooring system provided they are used correctly. The most important aspect is preparation. As for anhydrite not liking moisture it depends entirely what you mean. There are so many myths about moisture and anhydrite it's hard to even begin to unpick them all but the vast majority are based on bull wotsit.
If you want to use 404 over 85% rh you need to use it with pe425 primer. One of the things I didn’t like about that primer is you need it to seep into the anhydrate for it to work. Maybe they have changed their minds as a few years ago slot of manufacturers didn’t recommend a dpm over them at all Sent from my iPhone using Tapatalk
you are correct about the fact that many suppliers did not recomend DPMs ot anhydrite. You may not know the reasons why. Welll, it's becasue the manufacturers of anhydrite did not recomend it. That was becasue, despite DPMs being used for some years, they had no research based data to be able to say what happened to the screed if all that moisture was "trapped" in it. as they were fully aware that the practice was happening they decided to do some research. The first official testing on this came around the mid 2000's in Holland. Amsterdam to be exact with Forbo Flooring supplying liquid DPM's for a large shopping centre project which was covered 7 days after installation. The UK industry has always lagged behind, and continues in many ways to do so. Perhaps due to attitudes to anything new and a basic mistrust of anything outside of the box. Nevertheless, we knew you flooring boys liked DPM's as builders are often a bit rubbbish at keeping buildings dry. In around 2006 one anhydrite manufacturer, at the time the UK's only manufacturer, did some research on this and found that actually the use of DPMs was not an issue at all as long as the screed was at a suitable stength for its application and was unheated. The moisture contents tested were considerably higher than those recomended. In order to ensure there was a good deal of engineering comfort built into this they recomended no higher than 1.5% moisture. This equates to about 87% RH on a properly calibrated hygrometer. At that point some of the manufacturers were able to start testing their own systems. Some got on board quickly. Some have yet to do so. In 2012 the other major manufacturer, carried out very similar testing but as that manufacturer was using different technology they were able to extend the 87% up to 92%. Then in 2015 the same manfacturer further extended research and did more testing first with Norcros to develop the Pro Gyp Base fast track system. At the same time Uzin were doing their own research in Holland on the same topic. They use different tech but the end result is that both can be used up to 95% RH. Ardex now also have a DPM that can be used on anhydrite at 95% RH. others will follow, and indeed may already be available but I dont know about them yet. Typically, based on good drying conditions and at 50mm depth Gypsol Classic screed unheated will achieve 95%rh in less than 7 days, hence the 7 days time scale. We have still never done any specific research that I am aware of with heated screeds because our view fis that because this shoudl be comissioned and run before covering the screed can be actively force dried making the use of DPM's irrelevent. If done properly this can dry the screed in less than 14 days. Additionallly we have things like Gypsol Rapide available now which again if done properly, dries in 14 days at 50mm depth. here endeth the lesson
That is interesting to read. I do appreciate your vast knowledge on these subfloors. I still never seen one dry out in the time stated. We use to put Ardex dpm1c over them after leaving them to dry for a month. No problems for us. Sent from my iPhone using Tapatalk
That was for a contractor that didn’t take moisture readings. Just dpm and crack on. Me personally. I would let them dry out as I have done since I worked for myself Sent from my iPhone using Tapatalk
And on that point you'll get no argument. Of course It's always best to let things dry but sometimes people dont do things right or circumstances change or programs tighten up and they need a backstop that works. Way back in 2003 there was no backstop. No DPM. No fast track. Precious little knowledge. Now there is lots of all those things. In fact there are several and various solutions to suit the various circumstances. Many of these I have had direct developmental contact with. The tech both with screeds and with post install products and systems has really advanced in the last few years. There are also a few really knowledgable and passionate people who are honest enough to say it how it is and not how they think it should be. I hear so much rubbish spoken about anhydrite it makes me sometimes angry and often quite defensive. after all, its paid my bills and fed my family since 1996.
Don’t forget your primer I can’t find anyone else that does a dpm system for wood or vinyl. Most of our prep manufacturers won’t get involved I feel. As youve mentioned before anhydrate can be dried much faster than traditional sand cement but that is reliant on a competent and knowledgable builder/main contractor (seems to be a lack of) and a better way of testing the moisture content. https://uk.uzin.com/products/best-s...st-method-for-damp-proofing-anhydrite-screeds Sent from my iPhone using Tapatalk
A mixture over the block, but high 80`s low 90`s. As you mentioned, we completed another site, where there was another stage to the process, with Uzin. Tbh, it took so long that the primer stage or it might have been hardener, just got dropped. Were on a 24 month retention with them, so I know there has been no issues. I personally don`t like anhydrite at all. It seems much weaker than sand and cement, and requires sanding etc. Not to mention always breaking in the corners where gripper is fixed.
