Plaster skim failed twice so far... what's happening?

[mycowhat]

Hello all.

I've had a full reskim of my new flat. A couple of weeks after the plasterer left, I noticed some balloons on one of the walls and when I picked at these, sheets of the plaster started coming away. It had not bonded to the original wall - it all came away when picked at. There were no cracks visible - just some areas that sounded hollow when tapped.

The plasterer returned and re-did the room but the same thing has happened. The thing is: the plaster has failed like this in two rooms out of 5 - the other 3 seem fine.

The building is circa 1900, lath and plaster walls. Wallpaper was removed prior to plastering. The plasterer has good feedback and a good reputation. There has been no heating in the house to dry the plaster out too quick. He used Thistle multifinish and definitely PVA'd.

I should also add: the finish on one of the rooms which failed seemed dusty - not shiny and smooth. Is this another unrelated problem?

I'm going to get him back to fix it again but I would REALLY appreciate any advice you guys could give beforehand.

Many thanks in advance!

K.

 

[Richard C]

It sounds like he’s not prepped it correctly & the skim hasn’t bonded. My immediate thought would be wallpaper paste residue, was it thoroughly cleaned off before skimming? Was there any paint finish on the original plaster? If so what type? Was there distemper or any other type of finish on the original walls? Did the new plaster come off clean or was there paint on the back of it. You say he used PVA, did he do this immediately before skimming or the previous day?

If inexperienced, it’s easy to make a mistake when prepping unfamiliar surfaces but to make the same mistake twice is careless to say the least; what’s the quality of his work like?

 

[mycowhat]

Thanks for your reply Richard.

The walls were stripped of the original wallpaper (by me) but I didn't do any other washing etc. I don't think the plasterer did either.

The plaster came off clean - no paint etc.

I'm sure he PVA'd immediately before the plastering but I'm not sure about whether he did it the day before he began the coat. The finish in the other rooms is excellent and he seems to have been going a while.

One of the walls which failed was onto the original plaster wall which is quite sandy to the feel. The other which failed was onto a painted surface.

I'm feeling like I have done something wrong to cause this but surely he shouldn't have plastered onto the walls if they were not suitable or not properly prepared?

Thanks.

 

[peaps]

I wouldn't PVA and skim a lath and lime wall, it's bad practice. Asking for trouble.

 

[cotswoldbuilders]

Although theres nothing wrong with pva, there are better bonding products such as,
Wickes PBA
Thistle Bondit
Febond Blue Grit

Being bonding agents they may be more suitable.

 

[peaps]

To seal a lath and lime wall is bad practice. You are asking for trouble.