Dot & Dab PVA

[Barry bp]

When i dot and dab i use diluted PVA on brick work.Just asking what anyone else uses as PVA a no no for tiling

[Scott]

I use it diluted for keeping the dust down on floors, obviously ones that arent being tiled.

[Alan.P]

I don't think I've ever seen pva used before dot and dab, not sure that it's called for, I'll have to check the spec sheets ????

[johnryan]

i don't think a primer is necessary for dot and dab to brick or block walls.

[macten]

I had to take all the plaster off a brick wall before I could board it and used diluted PVA to consolidate the dust first.
The drywall addy wouldn't have stuck otherwise.

[doug boardley]

in this instance I think it's fine, as long as it's well diluted and just used for suction control.

[nybor62]

pva is usually use on browning coat to stop finish plaster sucking to much , it would,nt hurt to put some on brick work just to eliminate any dust

[aph257]

i use SBR on brick work to keep the dust down as i always got some, so no need to buy/use pva.

[whitebeam]

I had to take all the plaster off a brick wall before I could board it and used diluted PVA to consolidate the dust first.
The drywall addy wouldn't have stuck otherwise.

I have never put any Pva on the wall before dry walling, damping the wall has allways been adequate.

pva is usually use on browning coat to stop finish plaster sucking to much , it would,nt hurt to put some on brick work just to eliminate any dust

If you put the finish on just as the browning is beginning to set there should no problem with any suction.

[QUOTE=Dan;487306]Let's point out what the problem is with it for most of us, it's the fact cement-based products mix with plaster which causes the two to de-bond (a tiny chemical reaction causes the two to sort of cause atom-sized explosions, causing the two particles to not bond). So providing we're not talking about cement on plaster, plaster on cement, I think there's no problem in using PVA.

Sirapite (a gypsum finish)was used on cement backings for a large number of years with no problems

[Stewart]

I did the drywall course in Penrith with Gyproc and the stressed you should only dampen the substrate with water when using drywall adhesive.

[johnryan]

I did the drywall course in Penrith with Gyproc and the stressed you should only dampen the substrate with water when using drywall adhesive.

that's what i thought. just splash water up the walls to dampen it a bit.

[Barry bp]

thanks for all your input two different plasters i have used do add PVA as long as well diluted I think for the time being I will carry on It does help with dust and stop brick and block drying too quick

[Dan]

[QUOTE=whitebeam;487319]I have never put any Pva on the wall before dry walling, damping the wall has allways been adequate.



If you put the finish on just as the browning is beginning to set there should no problem with any suction.

Let's point out what the problem is with it for most of us, it's the fact cement-based products mix with plaster which causes the two to de-bond (a tiny chemical reaction causes the two to sort of cause atom-sized explosions, causing the two particles to not bond). So providing we're not talking about cement on plaster, plaster on cement, I think there's no problem in using PVA.

Sirapite (a gypsum finish)was used on cement backings for a large number of years with no problems

i've erased my post. Doug said the same. i thought something wasn't right there with what I said.

I'll just shut up then lol

[Dave]

IMO, PVA should not be used where an adhesive type product..gypsum or cement based relies on it to create a bond.... SBR has been out a lot of years as well and much better a product..

The old PVA IMO is just a tradesman's tale that has always been used because they have never had a failure, a bit like adding portland cement to skim or base coats to make it set faster and they have never had a problem with the 2 products reacting..( Until it does)

I know a couple plasterers and they don't use pva.. 1 uses sbr and the other uses some sovereign gear not sure on the name.. but i am just a tiler.. who am i to quote plastering work..

[Barry bp]

On second thoughts i'll give up with PVA all together and use some SBR

[johnryan]

this might be helpful. dot and dab is page 18

http://www.british-gypsum.com/pdf/LI...onGuide_02.pdf