Suction

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Basher

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Just doing a re-furb for a company and they have hack off most of the plaster from the kitchen walls and i have to float and set them all, The problem being the bricks are bone and i mean bone dry! so i pvaed the walls and gave them a scratch and a float coat is this the best way to be done or is there another method of stopping the suction many thanks lads
 
if its brickwork i just give em a good soaking with water then hardwall its designed for these applications but pva wouldnt hurt
 
i had float and set on bone dry clinker blocks a few months back, i gave em a coat of very thin pva, hardwall and multi as usual, worked fine, at least no comebacks yet!
 
pva shouldnt be used with hardwall......me personally i would soak the wall then use universal one coat plaster, let it set then skim same day...or next pva it then skim
 
i allways pva brick work? for patchs and all ect useing mostly bonding and some times hardwall
 
Cheers lads i have been using bonding does anyone allso use tough coat the builder bought a bag of it for monday and not used it before many thanks
 
pva stops suction or at best seald , hardwall was designed with suction in mind its a high suction plaster..no need to pva......your stopping it from doing what it was designed to do cause your using pva to form a barrier between substraight and plaster
 
PVA slows down suction, I dont see any reason why you couldnt brush down an old brick wall then pva and hardwall .... I dont think its a problem

???
 
fair enough rich , but hardwall uses suction to adhere to walls why are you slowing that suction down with pva.....water and brush down brickwork , soak if need be but why waste money on a product thats not been designed to use with hardwall.
 
I do hear you Phippsy but each situation has its own problems etc im not saying you have to use pva but I dont see a problem with using it if the situation warrants it.
 
its just cause everytime i mensioned it to my mentor he bollocked me about it,
i suppose its like pva'in bonding next day when it was designed to be skimmed same day....
 
phippsy333 said:
its just cause everytime i mensioned it to my mentor he bollocked me about it,
i suppose its like pva'in bonding next day when it was design ed to be skimmed same day....
Click to expand...

LOL I do that as well sometimes haha .... maybe phippsy I am a right chancer and do everything wrong :( lol
 
lol nah you done sopme good work i can see that rich ...unless thats not your work on your site and you bought your tools on the way to the job today lol?
 
Busted ..... lol .

I sometimes bond out very heavy artex ceilings then give them a light scratch in a wavey pattern with my rendering scratcher then the next day use my spat to take off the high spots, pva and skim ... never had a problem yet... not saying its by the book either though. I dont think there is an exact science to plastering just do the best you can in a situation, as long as the finish is good then no problems

Rich
 
hardwall is best skimmed the same day as is bonding but as bonding takes so long to go off I usually do this last job of the day as I explained above.

Rich
 
mr 333 is quiet correct in saying that their is no need to be using pva when using thistle hardwall.it is a medium to high suction backing plaster.thuse eleveating the need to erase suction by sealing with pva.the area should be damped down to mearly get rid of any dust, and applied as per backing plaster.pva it seems is used in areas that its not required.and causes some confusion.why would somebody need to pva an area of high suction to use thistle bonding when its usage is for low suction substrates.it would seem that people first are unsure of what products to use or are unaware that what they are doing is counteracting what the product was intended for.i would also point out that in the case of hardwall as mr brown said it doesnt really matter weather you apply pva as it has no adverse effect.would you then apply hardwall to dense concrete block or plasterboard no.because it the wrong product,sousing hardwall in conjunction with a pvad substrate will in effect be the pointless. suppose some guys feel it like belt and braces double sure.but still the wrong product for use with pva, its strength is its ability of high bond to thirsty backgrounds.lessoned when used in conjunction with pva.
 
thats why these have been produced hence doing away with hsb which some of the oldies will remember just wet wall thats enough
 
If you have a read of the Thistle hardwall website it says walls of high suction to be primed with gyp prime to control suction, so depending on the situation pva will do just as good.

Rich
 
mr richard,i was not intending to doubt your advise,just point out that the need for pva is not essential or gypprime witch is a very expensive product.a good damp down will suffice.in the case of aereated block then as said an additional agent may be requierd.but not essential.i was trying to make the point that a lot of people rely heavealy on pva,rather than correct choice of material for the job in hand.mr monk i also remember when carlite made browning course haired stuff.and carlite finish wich was a far superior finish to the modern wait for ever multi finish, thistle only in those days did board finish, i may also add in man size bags not pocket size diy bags.
 
jeda is correct a lot of people rely on pva for everything and it is all down to the right plaster for the background there is nothing wrong with watered down pva to seal the the dust on brickwork but it shouldnt be used to provide a key for hardwall the bricks and joints provide a mechanical key. Always provide a key on your floating so whether you skim it same day or the next youve got the key and the pva can be used to give you a bit more time ie killing some of the suction.
 
sorry richard for starting the topic lol so what is the outcome i should pva to use hardwall and not for bonding lol sorry
 
lol! i used thin pva on the clinker blocks cos it was in a house that people are living in, soaking the the walls in an upstairs bedroom wasn't an option, hence, pva

controling suction doesn't mean killing suction.

in these situations common sense is king!
 
according2 gypsum website bonding is not for old common bricks, as they are high suction. So PVA'ing this type of brick makes sense to me.
 
what would make better sense would be to use hardwall or toughcoat as opposed to bonding surely?
 
or universal one coat...which im a great fan of..then skim...has very low suctioon same day too...but needs to be pva'd nexxt day if left
 
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