skim is coming off

[radroller]

hi lads , 1"m new to this site and was after some advice . i am a decorator and have been skimming the odd wall for about four years , but recently i skimmed a bathroom, unibonded all the walls and used muti finish good job so i thought. until now when i drilled a hole and some skim chipped off so i got a scrapper and a load more came off , but the first coat was fine it,s the second coat which has not adhered any advice where i went wrong

 

[pwi]

Possible first coat had dried out prior to second coat

 

[radroller]

that does seem to be the most logical answer . will i need to scrape it all down again and start again with pva

 

[bodplasterer]

What was on the walls when you skimmed it?

 

[radroller]

old sand and cement render , i removed the old skim , and pva the walls the day before

 

[beddy]

what ratio did you mix your pva?

 

[irish_spread]

old sand/cement needs to be well covered with pva just b4
you skim. dries out too quick plus all the above

 

[radroller]

i applied a ratio of 5-1 the day before skimming and on the day of skimming a ratio of 3-1

 

[irish_spread]

u still get v high suction on v old s/c so the 1st coat prob dried in 2 quick

 

[radroller]

so what would be the time scale between the first coat on the wall and applying the second coat

 

[irish_spread]

prob quite soon on old render. When the 1st coat starts to stiffen up, flatten it then put on 2nd
coat then trowel it when ready. Sometimes helps if you put an undercoat of bonding if
your not really confident

 

[beddy]

on sand and cement, i'd probably mix the first coat of pva a bit stronger, 2 coats of 3:1 would probably do it.

 

[church]

the first plaster coat being to dry when the second was applied would cause it to to shell , it depends on the suction but how long did you leave in between the two coats of plaster ?

 

[radroller]

about forty odd mins ,i just judge it by rubbing my finger into the skim and it was just starting to set, but it is shelling

 

[beddy]

jesus, thats why then

 

[beddy]

so the reason was possibly the 1st coat of pva didnt kill the suction enough, then you left it too long between 1st and 2nd coating the skimming

 

[radroller]

so i b*ll***s it up . ok so there no way this skim is gonna hold any tiles . so must i remove the skim and start again

 

[irish_spread]

Tile the render. NO HANG ON, PHONE A PLASTERER ;D ;D ;D

 

[roughas]

did u use frozen pva no only joking,first coat would of dried very quick on s+c probably would of firmed up after a couple of minutes of putting it on, you want to pva it up nicely put your first coat on as flat as you can then (dont wait) put your second coat on straight away then get back and flatten it should be ok then.

 

[beddy]

with sand and cement the most i've ever waited before second coating is a few minutes, 10 max. like paddyspread says, phone a plasterer ;D ;D

 

[radroller]

thanks very much for the advice .

 

[irish_spread]

with sand and cement the most i've ever waited before second coating is a few minutes, 10 max. like paddyspread says, phone a plasterer ;D ;D

OI- PADDYSPREAD ;D ;D ;D ;D

 

[radroller]

what would be my best course of action to removing the skim before making the phone call to the samaritans and a plastering firm :-[

 

[beddy]

from what you've told us, just fart at it and it should fall off ;D i'd say if it doesnt come off with a scraper then it'd probably be ok to skim over, its hard to say without seeing it.

 

[church]

if the first coat is sound just pva and plaster it again if not a razor blade scraper and elbow grease

 

[PhilPlaster]

from what you've told us, just fart at it and it should fall off ;D i'd say if it doesnt come off with a scraper then it'd probably be ok to skim over, its hard to say without seeing it.

;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

 

[church]

Next time use a product called stabilex made by artex as your primer coat .

 

[specific]

if you can't scrape it off,put thistlebond-it on and skim over.

 

[flynnyman]

It might have been the plaster, if i was you i would give British Gypsum a bell and ask them what the f**k are they playing at?

 

[Chris W]

It might have been the plaster, if i was you i would give British Gypsum a bell and ask them what the (french word) are they playing at?

;D ;D ;D ;D ;D yeuuuur! give em some sh't man!

 

[terry]

if the first coat is sound just tile over it.no need to two coat if its being tiled

 

[broonster]

you must rub up the first coat with a plastic float with nails to give the second coat a key,also a coat of PVA may help if the first coat has dried out.Hope this may help for the future

 

[beddy]

you dont to key the first coat at all...pva will be fine.

 

[plasterjfe]

if you pva the walls the day before that is prob what went wrong it dries like a shiny plastic layer (you remember from school) the skim can flake of this easy. you are suppose to skim onto STILL MOIST pva, or just use gypbond and then its a proper job.

 

[spunky]

;D ;D rubbish pva done the day before seals the old plaster then when you apply youre plaster you go over the next coat of pva while its tacky