Pva Versus Primers | Always Use A Primer When Tiling, And Not Pva

[fitzer]

Re: P.v.a. Versus Primers......

Just a quick question dave, what if you suspect walls have already been primed with pva - is there a primer that will counter act this? Also just to note, there are loads of different primers for different surfaces. Handy hint, if a bathroom has been stripped and premixed adhesive has been used if you apply pva bond to it, it will actually make it go soft with a couple of coats and it will come off the wall like butter. You point about pva - I have actually repaired a job where this has happened where a whole wall of tiles literally leaned away from the wall - some sight - sorry I didnt photo it - i normally use the technik evostick primer 918 - any of the brand name adhesives have a list of primers on there web sites for a list of jobs

 

[Jv40]

Re: P.v.a. Versus Primers......

What a great thread.

I wonder though is paint-primed new plaster prior to tiling as adequate as an intended tiling primer because I always believed this to be the case, and was told this on my course. Thanks Julia

 

[sWe]

Re: P.v.a. Versus Primers......

Here's a small post I made on Cement, Gypsum, Anhydrite, Ettringite Crystals, and PVA.

 

[Eddie]

Re: P.v.a. Versus Primers......

I have just been on the Weber site, checking out their gear. and found this. Weber PR370 is a synthetic water-based PVA concentrate. For sealing and priming building substrates.
Seals dusty or porus surfaces prior to tiling. If all concern about pva is justified, thats a bold statment from a company like Weber, or is this a different product all together?:huh2:

 

[Jv40]

Re: P.v.a. Versus Primers......

sWe

Your guides are... fantastic, superb, marvellous, knowledgeable.... :hurray: I think I've found them all now. My tilersforums.com lever arch is bulging and now has its own sWe Guides section. I'm a huge advocate of technical knowledge, the more I know, the better it must surely make me (imo).

In summary is it correct that contract emulsion for new plaster will suffice but any other substrate should be washed first with say sugar soap or at least tacked down and then correctly sealed?

The builder I work for told me last year that professional tilers do not prime their walls prior to tiling, including new plaster. I couldn't argue with that as I had no idea what professional tilers do, I just knew I had been taught to do it and that was that! He was upset because he told the customer I wouldn't be priming and when I did he thought it made him look an idiot!

 

[White Room]

Re: P.v.a. Versus Primers......

I've done site work for a contractor and never saw a bottle of primer although everything was dry lined, On a another job the walls was bucket gear (some tub gear state that no primer required) and that was on new plaster in a new private housing, Again no primer supplied. If your using cement addy on walls then it must be primed. I've used a mist coat of emulsion, artex sealer and sbr before and had no problems. The trouble with new plaster it's so absorbent and sucks the moisture from the adhesive giving it no time to cure properly, Thus giving in to failures at a later date.

 

[Viceroy]

Re: P.v.a. Versus Primers......

I,m totally confused with this !
I always used to pva diluted 1-4 plywood overlays (Never Had A Floor Fail)
then i was working with another tiler who used bal bond !
I Thought it was much better,so i started using that .
Talking to another tiler about it ,he told me the bal instructions on back of floor adhesive state you should only seal the sides and back face of ply ?
I now can't bring myself to tile directly onto a newly plyed floor without priming it !!!!!! so what do you fellas do on a newly plyed floor bond or no bond ?

Cheers

Viceroy

 

[DHTiling]

Re: P.v.a. Versus Primers......

BAL say you don't need to using there cement adhesives.......but other manufactures will say to prime...so always check on the bag.......

 

[Viceroy]

Re: P.v.a. Versus Primers......

Think youre right there !
Because Flexible profix (Dunlop) Say to use suitable primer !
Next job is with PCI
Tilefast 6 Rapidflex

The surface should be prepared to provide a rigid and secure base without deflection and suitable to support the
intended weight. Tongue and Groove/Chipboard must be over-boarded with exterior grade plywood which is at least
15mm thick and given time to find equilibrium with its surroundings. Plywood floors must be 18mm thick and all joints
must be supported. All must be screwed down every 300mm centers. The reverse face and edges of the boards must
be primed with Primer W to prevent the ingress of ambient moisture while the exposed face should be unprimed and
clean. Any existing wooden floor may also be over boarded with PCI Pecidur: minimum 10mm thick or PCI Polysilent:​

4mm or 7mm thick

Still not convinced about no primer !!!

Viceroy

 

[DHTiling]

Re: P.v.a. Versus Primers......

That also sez no primer...trust me i use BAL day in day out and it is fine......

Like i said if it sez prime then prime it if not then don't.......🙂..