Def sounds like they have zero clue what they doing, once it’s all lifted, source another company that has exp with gypsum etc
I read something about Etringite crystals but it didn’t really say what they were, or what the problem with them is.
They are caused by the chemical reaction you get when you put wet cement on gypsum / Calcium sulphate and they stop the two products but bonding Strangely if you put wet gypsum / Calcium sulphate products on dry cement it doesn’t happen
Pm me your number We are from Leeds and can grind your floor and install your karndean, we install lvt over gypsum on most of the work we do for a builder, he uses it all the time for his extensions.
Get a report done before you pull it all up. It will determine exactly what is wrong & what is needed to put it right, and most importantly you will probably need it if this all goes legal.
They've come an started removing it. Two days, and still need to come back for another. They used a machine with a 'blade' on the front and have gone through lots of blades. The screed underneath is fairly scored, but I guess that was inevitable. They've said the screed is powdery underneath and is showing damp on the meter. Now saying there's something wrong with the screed, maybe something left out of the mix, and laying blame on that. Also saying they showed a photo to a builder and he said that laitance doesn't look like that, etc.
And a close up of the area, which I'm guessing (as I can see aggregates) shows the laitance has come off at the same time.
That’s exactly what it should look like after the Laitance on the top has been removed There’s nothing wrong or missing from it And builders know nothing so don’t listen Needs a good vacuum and get the UFH running to help dry it out Don’t let them do anything else until it’s dry Probably two weeks but obviously it needs to be tested with a hydrometer with UFH off
Thanks Spacey. Just to confirm my first photo of the powdery bit, that is still laitance isn't it and needs scraping to look like photo 3? Would you still say it's 'baked' and would need grinding, or do you think that can be sanded? UFH water temperature hasn't been out of the 20s. Usually sits at 20, which is the lowest, otherwise it gets too hot. Your photo is darker than mine. I do have a very clean site.
Yes you need to see the aggregate on all of it like photo 3 Don’t worry about the colour difference it will just be a slightly different product
