Controling suction

[diysocket]

Hi, in need of some advice with plastering job. Having problem with plaster crazing which I know is too much suction. I really soaked the walls and applied plenty of PVA prior to skimming with new multifinish. The old plaster was removed.
The render is sand/cement I think, but the colour is light and creamy right thro which would suggest a lot of lime in what seems to be a very lean mix, it soaks water up like a sponge. Can anyone suggest a product and/or method to control the suction.
Thanks.

 

[Karis]

Can anyone suggest a product and/or method to control the suction.

I'm no lime render expert so can't advise there. But with a dry sand/cement render, forget the PVA & just water but lot sof it. A hose job & soak it 30 minutes before you start & let it drain but don't over do it or your plaster will just slide off!

 

[diysocket]

Thanks Karis, but as I said we soaked the render using garden hose and spray head, floor was awash so seeking another method for when I do the hall/lounge which has wooden flooring.

 

[peaps2]

water

soak 48hrs before then again the day you apply. water must run down the wall not suck in.

 

[roy c]

Paint neat sbr over all the surface of where you are going to plaster,dont add water to your sbr.Use a 6" brush and dont miss any of the wall when applying the sbr.Leave the sbr to dry (over night ) then next day when you are going to skim it do exactly the same again but you wont need as much sbr to cover it. Then leave that for a while to go tacky to the touch then mix your skim up (not too runny) then apply it then flatten it dont play with it !! leave it to pick up then 2nd coat it, you must know the rest..Bobs your mothers uncle

 

[peaps2]

don't waste a good wall by putting sbr on it.

 

[roy c]

He has said he cant soak the wall with water as there is a wooden floor there. I cant see anything wrong with sbr-ing it, it will seal the wall and kill the suction and he can skim it .No problem.

 

[peaps2]

we are both giving the wrong advice looking back at his post. It's already had a skim with multi so it would be a coat of bondit and skim..

He thinks the wall is lime so sbr wouldn't be a choice I would make. You an just as easily brush water on with a paste brush as you can sbr.

Damage is done now so thistle bondit or wicks equiv and skim.

 

[peaps2]

Just to add, PVA is PH neutral, lime is acidic when wet PH12. PVA degrades when acidic compounds are added.