Which floors to grind?

Is there a general rule to the types of floors that need grinding? It is mainly the newer pumped screeds, calcium sulphate, anhydrite screeds that need a good grind before prep?

 

All gypsum screeds do. Becoming a minefield now with lignite in a lot of screeds as well.

 

Yeh..noticed quite a few lately. Some worse than others. I think the customers thought I was talking shite. Either that or they dont want to pay for the grinding.

 

Most won’t want to pay. The builders don’t help as they say you can just go over it.

 

I had a discussion with a builder who built an extension for a customer of mine and when I told him about the process of the grinding he just shrugged his shoulders and said all other floorlayers he knows have just thrown a gypsum based screed over the top and has never seen anyone grinding a anhydrite floor

 

That's because he's cleared off before the fitter doses it!!

 

To be honest, we fit over it all the time without grinding.
I know its not how it should be but we do blocks and blocks on site and rarely have any issues.
Just a prime, and cheapest latex available.

 

Which primer do you use neil

 

We are labour only, so whatever they give us.
At the moment its Level it 2, so Prime it.
Ive used P121 with Green bag, the blue Ardex one with CL ,anything that`s on offer really.
Don`t get me wrong, im not saying its the right way, but it does generally work.

 

Savage

 

I bet you'd grind if you were supplying the covering,
A guy I know supply's to new builds doing carpets and LVT never ground and cement based screed, he had quite alot blow probably damp floor though

 

The screed supplier should be doing the grinding. Unfortunately most general builders don’t have the knowledge to enforce them to do it. They also seem to think it’s acceptable for their plastered to completely cover the subfloor with plaster. until they start getting billed for the extra work needed they won’t change.
Don’t mind grinding the off subfloor but not old asbestos adhesive

 

I rekon it has a success rate of around 98%
On big blocks, there could be around 10 different guys working, so there are often snags, but very few failures.

 

Yes, I would grind it if it were my job. Were set up for it, so its no problem.
If its not been tested and there is moisture, then yes, there will be a disaster. I also find that there is likely to be a problem, if were installing, before the windows go in

 

If anyone is interested, have a look here. Well worth the day out.
Floor Grinding Day 02nd June 2023 | Trade Discount Shop

 

Or here if you need to get up to speed with this
Tramex day Norwich May 26th 2023 | Trade Discount Shop