Hair line cracks in screed

Been to look at a job a mate has prepped,he has put down bonas moisture barrier,then put level flex screed,then fine flow over that.Amtico spacia tiles are going down,There are a couple of areas which have hair line cracks in the screed, he asked if it would be ok to put the Amtico down,i was unsure.any ideas?

 

It depends, cracks normally start to get bigger over time don't they! Is it all still stuck?

 

I gave it a tap all around the areas which have the cracks,and it sounded ok

 

I wouldn't care if it was sheet. Bit worrying when it's a tile. I had that with 300. Did 60 m2 for a shop, Amtico, all areas had bitumen on apart from the kitchen that was a really soft screed or repair compound, couldn't tell. Anyway the kitchen area was the one that had hairline cracks in it. I just fitted over it as it was all sound as you say. Been fine.

 

Did not take any pics,i did not think they would show up on camera,if i go back i will try some pics.
Its not for me a mate just wanted me to look,but i dont do enough of this to know for sure

 

had this last yr, funnily enough it was a water based (k11)
had a couple very minor cracks, tapped them, wernt hollow so were bonded ok, so feathered it to fill the gap
It was a really fine crack, i was just being pedantic lol
Still fine now
Was van gogh that went down, and no probs

 

Happened to me a few times with 300, green bag, mapei trade plan.
It can be the screed drying out a bit quick.
But as long as its solid and not loose or moving then no problems. Well I've not had any.

 

As cool said if no hollow points, do a hygrometer test just to be sure it's not a moisture problem then feather finish for a smooth as ass floor.

 

Cracks can happen if the mix is incorrect ie more water is added weakening the screed.

 

but not THE only reason
As a lot of folks, myself included dont put any extra water in the mix

 

The other reasons have been aforementioned CEA.

 

Some people add extra liquid to help the "FLOW" and not thinking about the consequences ie blown subfloors!.

 

I often get hairline cracks in mapei latexplan trade and you cant go wrong with that mix!?

 

Not had one crack on mine..

 

I think weve had this conversation before

 

neet primer allways works