Hi guys. We are currently going by colour and laitance to identify type of subfloor down. How do you guys do it?
Asked persimmons and Barrett recently. No one on site had a clue. And trying to get through to the right person at head office is a nightmare.
I am suspicious of any new build now. I always ask the builder if available. Appearance is a good start ( can look very similar to a floor smoothing compound), moisture reading can be another hint. It is getting more difficult!!
It turns to powder if you scratch the surface. But so does liquid cement. The colour is a give away but I’m sure there will be some companies that will change the colour of it. That sort of information should really be readily available from the builder or main contractor. Sent from my iPhone using Tapatalk
The builder hardly ever knows. Especially if they subby the bases. We done 3 David Wilson plots side by side one dark grey no lateince so standard sand cement. One with a badly laid powdery smoothing compound had to grind back. And one anhydrite. And since customer had come straight to us DW just fobbed them off.
13B5E773-CF2B-4857-8E57-58CFBFA91C78 by Spacey posted Feb 4, 2018 at 4:51 PM D75C2D63-08AC-4B95-901C-EAC014326F76 by Spacey posted Feb 4, 2018 at 4:51 PM DC4E1C40-7365-4421-9B73-569885DE7064 by Spacey posted Feb 4, 2018 at 4:51 PM[/[GALLERY=media, 1057]4D6A6B67-01EE-4D14-81CB-A72D93AF1EC1 by Spacey posted Feb 4, 2018 at 4:51 PM GALLERY]
I always ask the builder or the site manager if the screed is anhydrite or calcium sulphate. They usually look confused and say: "what?" Meaning they have never heard of it. I then ask the customer for an email description of the content of the sub floor. Then I usually hear no more. Loosing lots of potential work this way. Rather not be involved to be honest.
A good thing to ask the builder rather than what is it Was it laid before or after the walls went up? Anhydrite is always pumped in after the walls go up How thick is it ? Normally it will be around 35mm Concrete will be around double that Is there UFH ? It’s mostly used for UFH but not always If there’s UFH and looks like there’s fibres in it Then is concrete They don’t put fibres in Anhydrite Also it will be super flat
Not always super flat Spacey.. Whilst grinding most of the time you can see tamper marks or is that just on a Friday.. lol
Also we see mostly 50mm to 75mm thick anhydrite. Never seen one less that 40mm deep Sent from my iPhone using Tapatalk
You can do the milk test to check it. Pour cup of milk on it. If it turns pinkish it’s gypsum if stays white it’s concrete
Has to be full fat though doesn’t it ? Something to do with the lactose reacting with the callsium sulphate Milk is a great source of callsium That’s why plaster has that pink tone
