plaster cracking

Status
Not open for further replies.
T

terrymcb

New Member
hi , there.....new to this site
got a question , ive done a fair bit of skimming round own house and for friends ,ive all ways pva surfaces .but theres been a few times wen ive put the multi on the walls looks great first coat, then say 5minutes later look back and the plasters starting to split in places ,like starting to sag . so iam having to wait for it to set a bit before i can get a second coat on.
i no its something to do with the back ground but this has happen on a board finish and a cement wall . its starting to do my head in now because its slowing me down, i always water the pva down and then a thicker one on afterwoods, iam doing somethink wrong any help please, or is the mix to wet .....thanks
 
The pva and finish is sliding down the wall. Seen this a number of times on glossy painted walls.

Instead of pva, use a bonding agent on painted surfaces with no suction. Such as blue grit or wickes bonding agent.
 
Sounds like your rolling far too much pva on and going on a bit early mate. As said above its sliding down the wall.
 
Wrong type of finish, check bag and see if its for vertical or horizontal skimming

seriously though, pva , the day before or use grit pva as the guys said
 
alrite danny, ..wen u use a bonding agent do u hav to wait to it drys before u plaster or can u plaster wen it goes tacky ...some ones told me to use that thistle bond it but does the same proses applie to the other bonding agents . also if u have to wait for it to dry that means u would hav to go round the property the day before to paint and thats all time
 
terrymcb said:
alrite danny, ..wen u use a bonding agent do u hav to wait to it drys before u plaster or can u plaster wen it goes tacky ...some ones told me to use that thistle bond it but does the same proses applie to the other bonding agents . also if u have to wait for it to dry that means u would hav to go round the property the day before to paint and thats all time
Click to expand...

The wicks 1 can be gone over in a couple of hours
 
that sounds ok then ,ive got a bedroom ceiling and walls to do.
so by using that bonding il no it should kill the suction , so would it give me a little more working time to get the skim on
 
terrymcb said:
that sounds ok then ,ive got a bedroom ceiling and walls to do.
so by using that bonding il no it should kill the suction , so would it give me a little more working time to get the skim on
Click to expand...

Sort of, it depends whats on the walls.

One of the skills you'll need to get your head around is evaluating the background and how fast it will pull in. (how porous it it)

On a shiny background the suction has already been controlled (too well sometimes) by the paint. So your objective is to prime it so the plaster doesn't slide, bonding agent alone will do this.

On a high suction background your main aim is kill most of the suction primarily as well as stabilize the dust. There are a number of ways this can be done, a lot of people just use PVA starting with a weak solution and making it strong in each subsequent coat. This works well but on real high suction you might need as many as 5 coats if you want to put a good amount of finish on.

Another way is to give the wall a coat of PVA or SBR to kill the dust and some suction, then bonding agent. Microgobetis is the best for this IMO. This way you're only coating the walls twice, you have piece of mind that the finish will grip well and have a slow even pull in.
 
A think thats all he is doin rong just needs to wait a touch longer to go tacky , sum times one bit might be tacky but the rest hasnt picked up yet or sum where there isnt much suction and the pva is hanging there , not bad puttin the plaster on its next time over it and its stiffinin up and jus slides on the wet pva behind it also seen it sag with out troweling over sliding by its self , that wasnt me by the way !!!
 
CTPlastering said:
A think thats all he is doin rong just needs to wait a touch longer to go tacky , sum times one bit might be tacky but the rest hasnt picked up yet or sum where there isnt much suction and the pva is hanging there , not bad puttin the plaster on its next time over it and its stiffinin up and jus slides on the wet pva behind it also seen it sag with out troweling over sliding by its self , that wasnt me by the way !!!
Click to expand...

:RpS_laugh:.............you fu@kin fibber carl
 
Thanks for that dan,

What it is my partners a decorater and she normally goes into jobs and would advise the client that the walls need plastering because it might not be cost effective to have to wall lined with paper.

I have trouble doing big hits, recently I had to do a ceiling and it was about 25 sq metres and it was a hot day, and I got 3/4 a way across and I went back to the start and it started to go, so I got the rest on and the woman come out and said that it looked ok but as you know when its wet it looks fine, but as I'm walking away Im thinking to myself I'll be waiting for a phone call. So I went back to the persons house the following week to re scim it, as my dad always said you always learn the hard way boy. No ones ever shown me nothing, I've just had to learn myself. My works always come out good but I have trouble doing big hits through the suction on the surfaces, I can't get it right.

I think this is a great site, cheers lads
 
terrymcb said:
Thanks for that dan,

What it is my partners a decorater and she normally goes into jobs and would advise the client that the walls need plastering because it might not be cost effective to have to wall lined with paper.

I have trouble doing big hits, recently I had to do a ceiling and it was about 25 sq metres and it was a hot day, and I got 3/4 a way across and I went back to the start and it started to go, so I got the rest on and the woman come out and said that it looked ok but as you know when its wet it looks fine, but as I'm walking away Im thinking to myself I'll be waiting for a phone call. So I went back to the persons house the following week to re scim it, as my dad always said you always learn the hard way boy. No ones ever shown me nothing, I've just had to learn myself. My works always come out good but I have trouble doing big hits through the suction on the surfaces, I can't get it right.

I think this is a great site, cheers lads
Click to expand...
Practice is the key but you need to work with others who,are good
 
Status
Not open for further replies.
Back
Top