Self levelling screed???

[Daz]

I thought that one of the benefits of gyvlon screeds are it's self levelling capabilities - have I mis-understood?

screed 2.jpg


screed 1.jpg

This is what I was faced with on Tuesday and the customer expected me to fix 600 x600 porcelain .

[Brinkley]

looks like the rockys captain

[Bri]

Few bags of SLC then!!!

[DavieA]

More SLC required then?

Mapei renovation seems to be highly recommended 30mm and only £11 a bag.

[jay]

dont you just hate it when you have large format tiles to lay not the best captain

[Ajax123]

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.........

[Daz]

You are absolutely correct, there was a substantial amount of making good. However, my query is with regards to Anyhdrite / Gyvlon screeds. I thought they are supposed to be self levelling?

Was typing at the same time as Alan, so these comments do not apply until I have read the post from Ajax

[Brinkley]

are you able to put a slc over a gyvlon screed ajax and if so does it need longer to dry

[Ajax123]

are you able to put a slc over a gyvlon screed ajax and if so does it need longer to dry

Yes you can put SLC over Gyvlon. I would always recommend one based on Gypsum so that it is fully compatible with the screed and eliminates the risk of chemical delamination. All the same rules apply in that the heating must be commissioned, the screed must be dry, surface must be clean and sound etc.....

[Daz]

Alan, this is the very same screed that you viewed with me in November. It looked alright then didn't it . I have lightly sanded the screed (I will provide a full anhydrite thread for forum members soon) and found no cracks whatsoever. The screed is even in colour which, to me, indicates an even moisture content too. I can't see any obvious reasons for the screed to be so poor which is why I asked the question. I'm really disappointed with the installers.

[Ajax123]

Not surprised you are disapointed. We didn't look at flatness when I came. Assuming your bit of wood is straight it looks well out. Which addy did you go for in the end was it the weber? .........they also do a gypsum based leveller, as do many others nowadays .......

[jay]

just out of interest should the supplier or screeders be called back to rectify the floor as its not really acceptable

[Daz]

I admit that my "straight edge" in the pics is just a random floor joist that I found lying around. I should have placed my spirit level on top to illustrate the point better. I demonstrated the problem to my customer with my 1800mm spirit level and it was just as bad, so much so that we had to check the window for level too. The dip was peaking at 25mm over 2.5 metres (if that makes sense) and fortunately appears to be quite localised as the rest of the 75sqm seems pretty good.

Yes, I am working with Weber on this job and will provide a review when the floor is completed. I have, also, offered to provide Weber with detailed feedback too.

[jay]

e dip was peaking at 25mm over 2.5 metres (if that makes sense)
so it has a walk in shower area

[Daz]

just out of interest should the supplier or screeders be called back to rectify the floor as its not really acceptable

In this instance, it is in no way the suppliers responsibility.
The installer would normally be expected to rectify the poor installation, however, there is a major breakdown between client and installer (builder) as this is not the only issue that my client has experienced, so they are happy to compensate me to sort the screed.

[Daz]

e dip was peaking at 25mm over 2.5 metres (if that makes sense)
so it has a walk in shower area

, I did suggest that I just install a drain and tile with envelope cuts.

[Ajax123]

just out of interest should the supplier or screeders be called back to rectify the floor as its not really acceptable

Why should the suppliers be called back?????

[jay]

oh just wondering as the problem is handballed around screeder will blame supplier ect best to get them both back to find the prob no disrespect Ajax

[Ajax123]

oh just wondering as the problem is handballed around screeder will blame supplier ect best to get them both back to find the prob no disrespect Ajax

no offence taken Jay. Was just curious to know why you thought supplier would be interested. You are right though that these sort of complaint often start off with the installers blaming the material.

[Dave]

I thought that one of the benefits of gyvlon screeds are it's self levelling capabilities - have I mis-understood?

screed 2.jpg


screed 1.jpg

This is what I was faced with on Tuesday and the customer expected me to fix 600 x600 porcelain .

Ha, now this depends upon the screeder daz..

It is all in the pour.. correct ratio/mix is the key..

looks like too dry a pour to me.. or maybe a Shyte screeder

[Dave]

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.

[Dave]

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

[TF Ed]

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