Self levelling screed???

[DHTiling]

I will say in my experience these screeds are very very flat normallly but lafarge are not held responsible for screeder error and this s deffo screeder error.

 

[Daz]

I will say in my experience these screeds are very very flat normallly but lafarge are not held responsible for screeder error and this s deffo screeder error.

I agree Dave, this thread was in no way aimed at bashing a supplier / manufacturer. I just wanted to clarify that I was correct in assuming that one of the key features of this type of screed is it is self levelling.

 

[DHTiling]

Tes deffo it is.. but on delivery a screeder should do a slump test and if the mix is too dry then he.she should alter the water ratio and if it is too wet then send it back.. screeder knowledge is the key here.. but that what you have is wrong..

 

[jay]

😳 what have i done

was not blaming supplier just best to get all bases covered and give the supplier a chance to explaine to customer the reason for floor finish (which is out of there control)but will more than likely get blamed

 

[Aston]

Oh my giddy aunt. That is awful. Is that dips between the pipes (I assume its UFH). This is called pipe mapping and it is caused by one of 3 things.

1. Pipes not fully secured ad have floated - this usually is patchy and sporadic and does not appear to be the case here
2. The screed is placed too thin with a lack of cover to the underfloor heating pipes. This leads to a differential between the level of plastic settlement, a natural function of a flowing screed (self levelling compound does the same thing), between the pipes being greater than that over the pipes. It is often accompanied by cracking across the tops of the pipes
3. The screed has been placed too wet which leads to a similar phenomenon as described in number 2.This scenario is also often accompanied by level issues as the excessive water content in the screed bleeds to the surface and makes it difficult for the installer to differentiate the actual top of the screed and the bleed water on the top. It is also often accompanied by soft powdery patches often in door ways where the bleed water gets chased and causes the screed to segregate locally.

If it is installed correctly then it does exhibit self levelling tendencies. In terms of deviation from the straight edge I would expect in a job of this size that there would be little to none but the screeders generally should install to SR2 as an absolute minimum standard.

You will presumably use a smoothing compound over this one - I would suggest one based on Gypsum. Also are you uncoupling cos that level of "defficiency" could also lead to the screed cracking under thermal loading.........

al, you took the words right out of my mouth
seriously, cracking diagnosis mate !!

ed