practice plastering.

[richard1600]

hey guys,,, we have a few walls in our house are coming down so decided to try save money in the long run by doing some plastering,,

we dont have a proper mixer so we did it by hand and using a wisk on the end of a drill to get a nice consistency,,,

were getting the technique ok and the more we do it the better it is., however,, one wall completly cracked,, me thinks background was a wierd shiny bumpy thing from the 70's so we redid using pvc etc.

we now pvc and score all walls and still we get a few long large cracks a week after drying,, any advice on anything i said would be much appreciated..

also what is the correct mix of water to powder? is there a rule of thumb or just you know when you know ?

 

[keyplayer]

we now pvc and score all walls and still we get a few long large cracks a week after drying,, any advice on anything i said would be much appreciated.

Pva works better than pvc.

 

[richard1600]

love,,
ahh thats were i must have gone wrong !!

lol... doh what an idiot, must of had something on my mind,, pva.... lol

 

[Richard C]

OMG wots happening, am I avin a nightmare

 

[stevethespreader]

ok you plastered a background that was shiny and bumpy and it was from the 70s it wasent kojaks head was it? only joking lol cant u find out what the background is?

 

[roy c]

If you have plastered over a cracked surface without taping all the cracks(preferably with 4" scrim tape) then that is the reason the cracks are showing through later on......

 

[richard1600]

that first background is not an issue,, that wall is now ok after re-doing it,,,

but our walls either sides of stairs were wallpaper, so were steam stripped all wallpaper, had a bit of a sand down, filled some gaps,, sanded,, it was all smooth no cracks,,, so we scored it pva'd it and plastered, spoent a while on preparation,,,

the plastering looks great,, until a week later i have 3 long surface cracks, 2 on 1 wall 1 on the other??

it cant be the background??


also,, whats the score when plastering staright onto new plaster baord,,,

thx again

 

[NickB_99]

also,, whats the score when plastering staright onto new plaster baord,,,

Don't understand your long surface cracks, but for plastering straight onto standard wallboard, ensure you fix it with the ivory/lighter side outwards and you skim straight onto it. No PVA necessary.

 

[noseall]

Let us not forget here, that over-skimming existing walls is never 100% reliable and the customer should be made aware of this.

In t' old days (pre-pva) it was normal to remove existing plaster back to bare brick.

Over-skimming is a convenient way of dealing with artex and poorly finished walls but is by no means belt and braces.

I have seen instances where an over-skimmed wall has cracked horizontally as soon as paint was applied.

 

[Richard C]

As per Roy c; if you filled the gaps/cracks & just skimed over without applying any reinforcing tape, they will almost certainly reappear again when it all dries out no matter how smooth it looked. If the cracks were more substantial, the plaster has to be removed right back locally to see if there are also cracks in the bricks/blocks. Sucessfully repairing these is possible but involves considerably more work as they have to be reinforced with a wide metal lath & re-rendered before any attempt is made to finish plaster.

 

[richard1600]

hmm ok,, i thought i was getting the mix wrong or something,,

also with regards the lighter/ivory side out,, lol,,

is it pos to plaster on the other side,, one of our ceilings (bedroom) fell through due to roof being remade, so i put up temp plasterboard with view to getting a pro to plaster it at a later date,, however its all the darkside down,, DOHHHH... learn by mistakes,, will a good plasterer be able to overcome this ??

 

[Richard C]

It won’t be a problem, just means he'll have to do additional prep first but be ready for some jibes of ridicule like, “which part of plaster other side don’t you understand mate” but they don’t all say it.

It always pays to do your research before rather than after youve made mistakes . A read through the forum archive posts would have prevented you making the ones youve already made & may help prevent you making further ones in the future.