I'm Confused About Priming!

[Brad]

hi all. very confused ot the mo'. just been looking thru' a bal technical data sheet and it suggests NOT priming a ply wall prior to tiling. I've always thought that that's what MUST be done???????

also, can anyone advise on priming onto old plaster, cement, etc...... does old need to be primed?

thanks

[david campbell]

plywood defo needs primed,,prime old plaster too!

[Paul Linley]

Looking through The "bal profesional fixing guide it states that blue/green or white star can go straight on to plywood with no suggestion of a primer been used. hope this helps.

[bigandy]

It depends on what manufacturer you use, some addy's require priming some don't. If your not using the same the same company you will need to check the individual product.

[woodie]

hi buddy, it's up to you to be on the safe side i know there are addys out there these days which are 'self priming' so you don't need to prime up as for plaster walls, new definately prime because it will draw the moisture out of the addy and make go off too quick, old plaster not necessarily need to prime as it won't draw out the moisture

[atec]

i would prime rear and sides only prime front if instructed to by manufacturers guide. plaster as stated by woodie, though i would prime old plaster also

[beanz]

i would prime old plaster also

Same here, if you're using a cement based Addy. Old plaster may not suck the water, but you could still get Ettringite failure.

[Billy Hunt]

Same here, if you're using a cement based Addy. Old plaster may not suck the water, but you could still get Ettringite failure.

Like it beanz,but what does Ettringite mean?

[Dave]

Like it beanz,but what does Ettringite mean?

Have a read of this... CTIOA FIELD REPORT 100

[beanz]

Saved me a lot of typing there Dave.

[Dave]

Saved me a lot of typing there Dave.

And me...

[doug boardley]

but I'll bet Dave and Marcus can type it from memory..........lol

[sWe]

There are three general rules when it comes to priming:

1. Follow the manufacturer's guidelines. If the specs of a particular adhesive says that a particular substrate needs to be primed, then you should.
2. Gypsum and anhydrite substrates need to be physically separated from cementious materials.
3. PVA is NOT a primer, and does not belong in the world of tiling. Period.

More on the subject of ettringite, primer, etc... sWe's guides

[Billy Hunt]

And me...

Yeah, silly me it was so obvious

[Dave]

Yeah, silly me it was so obvious

You don't ask godders you dont get to know.......it is all there in the link...hope it helped..

[Billy Hunt]

You don't ask godders you dont get to know.......it is all there in the link...hope it helped..

"godders?" now thats scary,cheers dave

[atec]

does tanking count as a primer

[sWe]

does tanking count as a primer

Tanking counts as a physical barrier between the substrate and the adhesive. I assume your implied question is "do I need to prime tanked surfaces?", and the answer is "no, you don't". Just make sure to follow the application guidelines of the waterproofing system you use. You may still need to prime before applying the actual waterproofing, in order for it to stick properly.