Does PVA go off..

[adam81]

Had a plasterer in who's had no end of grief, with his plaster drying out too quick. I had some PVA left over for last time I had plastering done (24 months), and bonded all the walls with this.

Does PVA have a shelf life, there's a lot of crazing going on, with cracks as soon as the plaster is applied. Is it worth just keeping misting the walls as they dry out to give them as much water as possible?

 

[Richard C]

Not to my knowledge but it can thicken up if you store it too long after opening. A few years ago I inherited a ¾ full 50 litre drum of the stuff from someone who used it as adhesive for the homework job they did, it was at least 5 years old before I started using it; all long gone now but had no problems with it. I’ve also stored left over thinned PVA in an old sealable emulsion bucket, it can be a bit smelly when you re-open it but, again, I’ve not had any problems using it.

Who supplied the plaster, did you/he check the date on the bag? What’s on the walls? Paint? What sort of paint? Didn’t your plasterer bring his own PVA? Didn’t he apply more to the walls before he started plastering? It sounds like he’s had a problem either not controlling the suction or used out of date plaster; are you sure he’s actually a plasterer?

Ive used mist spraying on Bonding plaster over high suction backgrounds before to prevent crazing but never on finish; if you put too much water on there the surface will just turn to mush.

 

[adam81]

I supplied all the materials bought from wickes the day before he started.. All bags were date checked, good until November according to the bag.

I've had him to do jobs before for me and other family members too and was more than impressed with the results previously.

The walls were painted, impossible to tell what sort of paint really though, especially now as its covered up.

Yeah PVA was applied before he started too, it's obvioulsy a suction issue but he claimed he's never come across anything this bad before. I've got another room to do but that doesn't have any paint on the walls. I stripped back the wall paper to reveal bare plaster. The other room was paper over paint.

 

[roy c]

I supplied all the materials bought from wickes the day before he started.. All bags were date checked, good until November according to the bag.

I've had him to do jobs before for me and other family members too and was more than impressed with the results previously.

The walls were painted, impossible to tell what sort of paint really though, especially now as its covered up.

Yeah PVA was applied before he started too, it's obvioulsy a suction issue but he claimed he's never come across anything this bad before. I've got another room to do but that doesn't have any paint on the walls. I stripped back the wall paper to reveal bare plaster. The other room was paper over paint.

When you say it was put on before he started was it put on 24 hours before he started? It needs to be put on 24 hours before he starts.Then before he starts to plaster you should put some more on and let it go a bit tacky. I have found the best way to apply it is with a roller and a roller tray. Mix it up at 4-1...Dont "scrimp" with it let it run down the walls....

 

[stevethespreader]

Yeah PVA was applied before he started too, it's obvioulsy a suction issue but he claimed he's never come across anything this bad before. I've got another room to do but that doesn't have any paint on the walls. I stripped back the wall paper to reveal bare plaster. The other room was paper over paint.

if he cant control suction hes no good as a spread you have to use water, if its sucking badly the wall wont go mushy, and i know a lot of you don't like the sponge float but its a beautiful tool in a situation like that, and im not sure it was sucking that badly if the walls had been previously painted, how would he get on with really porous old lime walls? he wouldn't stand a chance, please don't say your going to let him plaster your other room?

 

[adam81]

The finish he achieved on all the walls in the end was very good, he was spraying them down a lot more than he usually would, and it took a lot longer too, the reason for the initial question as to the quality of old PVA.

So he is back in the other room today. Might be an extra day to complete it all though.

there's a lot of crazing going on, with cracks as soon as the plaster is applied

Read more: //www.diynot.com/forums/viewtopic.php?p=2071038#2071038#ixzz1U96BpnQ2[/QUOTE]

He noticed this and drowned accordingly, or at least to my eyes he did..

 

[stevethespreader]

So he is back in the other room today.

 

[adam81]

Yep and all super smooth.. Said this room was much easier as it was bare plaster, so something up with the paint I guess

 

[stevethespreader]

so something up with the paint I guess

it would have been his lack of prep not the paint, some paints need more than pva such as bonding agents, still im glad your other room came up nice