I can't stand these screeds

[Pebbs]

I know people have ranted about these gavlon screeds, but I want to rant again, the job we are about to start has them running in every area. So I have hit the roof, as we weren't told, am I 100% correct in thinking they have to be sanded and primed before we can start works?

Time for a workshop with me Ajax I thinks.

Lynn

 

[bugs183]

Hi Pepps!
So that's knackered your price then already!
They need sanding, as for priming it depends on which adhesive you'll be using so thats down to the manufacturers spec.
I hate these screeds too, i'll be doing everything i can to avoid them!

 

[nybor62]

hi lynn

the last time i did one , it was low latance, and the main contractor was advised it did,nt need sanding, not sure if that advice is correct though, we did use gypsum based addy and primed twice , and as far as im aware the floor is still intact, there was no under floor heating

lets see what ajax has to say

 

[Gazzer]

According to Alan...ALL floors need sanding.
As for what method you use is a big question. Prime and your usual adhesive (if suitable) or a Gypsum based adhesive. I opt for the Gypsum Adhesive ( N&C Gypfix) This is stated as no priming needed.

 

[The D]

According to Alan...ALL floors need sanding.
As for what method you use is a big question. Prime and your usual adhesive (if suitable) or a Gypsum based adhesive. I opt for the Gypsum Adhesive ( N&C Gypfix) This is stated as no priming needed.

I don’t know if one is required on this job but just so we all know N&C Gypfix is not suitable for use with a uncoupling mat.

 

[bugs183]

There's mixed views on uncoupling mats and gypsum screeds, as usual with these screeds and adhesives!
I've just layed 63m2 of Slate onto a two year old Anhydrite screed, i used GBTA adhesive, it cost £700+ delivered and include the primer, mental money.
The screed has been down two years as said, so has been highly traffic'ed, this needed removing, but the screed was so hard my customer couldn't sand with a normal sander, he had to use a belt sander like you would on a floor, the dust was unbelievable, it was everywhere!!!
So glad i hadn't priced for that!!

 

[Diamond Pool Finishers]

They are rubbish screeds :mad2:

 

[bugs183]

I really wanted to embrace them (because we're being forced too).
I talked to all the manufacturers, the screeders, testing companies you name it. No one is responcible for each phase, everyone has the best product, but each one showed itself to be flawed. I just completely lost faith in these floors.
Bottom line. 20 years ago adhesives had to be modified to be used with Porcelain, ''never fix porcelain with gysum products' we were and are still told.
So now it's fine to fix porcelain with gypsum compatible products. Mmmmm, my hands had no adhesive residue after using these adhesives, the tools were easy to clean, and my tests left me with little confidence on their ability to stick porcelain.
Who sands the floor???
Who tests the floor???
Which adhesive to use, and how to explain to the customer their fast track cheaper floor is in fact anything but!!!
Bored of it now, but above all, i'm not confident in what i'm being told, so i'm out.

 

[Pebbs]

Well here is the latest update, apparently the screeders have been informed that the substrate has to be prepared in advance for us to tile onto. So yes I have thrown the ball straight back at them, I foresee a delay and a lot of cursing (well even more than normal).

They better pull their fingers out and get a move on, or I will be on the warpath in my little safety boots.

Lynn

 

[bugs183]

Good stuff Pbbs, go get'um.
What about who's testing the dryness of the floor?????? Has that been mentioned?

 

[Ajax123]

Well here is the latest update, apparently the screeders have been informed that the substrate has to be prepared in advance for us to tile onto. So yes I have thrown the ball straight back at them, I foresee a delay and a lot of cursing (well even more than normal).

They better pull their fingers out and get a move on, or I will be on the warpath in my little safety boots.

Lynn

good for you lynn

to put it simply all screeds should be clean, dry, sound and free from contaminants likely to cause a failure. Anhydrite screeds should be sanded to remove any laitence or other residue from installation or construction. They should then be vaccuumed to remove the dust from sanding. They shold be inspected just the same as any other substrate to ensure they are not cracked, falling apart, fractured, soft or deficient in any other way that indicates a potential issue. If the surface is contaminated with anything like oil or deisel (usually localised contamination) these areas will need to be treated with a suitable primer e.g. Water dispersed epoxy. The screed should be checked by the man contractor to ensure it is dry. I always Recomend a second check by the flooring contractor simply on the basis that site managers don't always tell the truth. Assuming all the above is ok The need for primer will depend on two things one is the type of adhesive selected e.g. If its cement you will deffinitely need to prime, if its gypsum you may need to prime (manufacturers instructions). As a rule of thumb if the surface of the screed is very porous prime it f it is hard and dense then you probably won't need to. This is a judgement call really as I cannot see the screed. You could do a water droplet test. Drip a few drops of water onto the screed. If the disappear immediately then it is very porous. If they sit on top of the screed for more than a couple of minutes then it is not. In all cases if in doubt prime it anyway. If you use cement adhesive you are better to use an epoxy primer but if you use gypsum you will be fine with an acrylic.

I know... Clear as mud.... Hope it helps though ... If you got any specific questions fire away....

 

[Pebbs]

I will do another email tomorrow, with this all thrown in for good measure, or I can see it all ending in tears...mine normally.

Thanks for the tech stuff, we really have to get our heads around this screed, every single contract Im quoting for now, Im asking the question..what is the screed? Wish I had done this a few months ago.

Lynn

 

[Ajax123]

I will do another email tomorrow, with this all thrown in for good measure, or I can see it all ending in tears...mine normally.

Thanks for the tech stuff, we really have to get our heads around this screed, every single contract Im quoting for now, Im asking the question..what is the screed? Wish I had done this a few months ago.

Lynn

i shall contact you in the next few weeks to get together to go through anhydrite once I get my head round the new job.

 

[Pebbs]

Thanks to Nybor today, because I was in a bit of panic, and wanted to move this job along. So I have now ordered the epoxy primer, because if I wait any longer we will be starting this job after christmas. I did try to find Alans number but I couldnt find it anywhere.

The wheels are turning, bit slow though, never mind better than standing around doing nothing.

Lynn