Problems with re skim following damp porring - sounds blown / hollow

[Psk]

Hi

We have recently had fairly extensive damp proofing on the ground floor of our house. In one area adjacent to the stair case only part of the wall was treated, with the original plaster and render removed, some dubbing out and damp proofing substances applied and the area reskimmed. This are borders onto the original plaster which was unaffected.

We've had a succession of problems, starting with large cracks in virtually all areas. The weather was very hot at the time the work was done and we understand that this was due to the large volumes of sand/cement and plaster applied in a short time. The contractor has filled most of the large crack which seems to have worked fine, however in the staircase area the plaster was also blown.

In this area the contractor returned, applied a retaining tape to the largest cracks, and reskimmed. Now this has dried there is some minor, but still in need of fixing, cracking returned, and also several hollow sounding areas around the border between the new plaster and old. The contractor has now become quite unhelpful and insists these area are not a problem, and that the hollow sounding areas do not indicate blown plaster, or should be of concern.

I'm not a professional plasterer of course, however I've had much plastering done on several properties, and at no time had any problems like this. I don't feel like it is fine for there to be these hollow sounding areas, or for this part of the job to be "as good as we can get it" in the contractors words.

They are sending out the plasterer again to have another look, however he has told us he is sub contracted by them, and isn't being paid to make these remedial repairs, which makes me suspected he is not going to want to spend any time carrying out further remedial work, and may well follow their opinion that there is no problem.

Any advice gratefully received, the contractor is a member of several trade bodies, however I'm not at the point of contacting them yet (they state I should go through a the contractors formal complaints procedure first, which I'm happy to do if necessary).

 

[adapt]

Sounds to me like it needs to be hacked off back to a solid substrate and re-plastered.

The problem could be the area might not have been primed correctly and if they have dubbed it out on a hot day without wetting down the walls correctly then you will have issues with blown plaster.

Just tell them the plaster has blown and you want the boss down there to sort it out.

Fast enough taking the money off you.

 

[Psk]

Thanks, we haven't paid them anything other than the initial deposit at the moment, so at least have that. We've been dealing with a surveyor for the company who was at first very helpful but now has become quite dismissive and rude about it.

They're sending round the sub contracted plasterer they use again on Monday, however I suspect he will under instruction to only repair the new cracked areas that have appeared, and not that blown areas which the surveyor claims aren't a problem. If this is the case we plan to tell the plasterer we'd rather he did nothing to the wall until we can reach an agreement on what needs doing.

Also have another plasterer coming round tomorrow to quote for a different job so he is going to give us a 2nd opinion.

 

[Arti]

Did they leave the sand & Cement to cure 3-5 days before they skimmed it?

 

[Psk]

No, the whole job from hacking off the old plaster and render, dubbing out, damp proofing and re skimming was completed in about 5 days. We understand that especially in the hot weather each layer should have been allowed to dry more before the next was applied, would you agree?

The other areas, including the ones that needed the most extensive dubbing out, have been more or less fine (some cracking aside which has been filled with no problem).

 

[User___removed]

No, the whole job from hacking off the old plaster and render, dubbing out, damp proofing and re skimming was completed in about 5 days. We understand that especially in the hot weather each layer should have been allowed to dry more before the next was applied, would you agree?

The other areas, including the ones that needed the most extensive dubbing out, have been more or less fine (some cracking aside which has been filled with no problem).

When carrying out these works each coat should be no more than 10mm in thickness and left to dry before next coat is applied.
Most jobs like this need 2 scratch coats and a float coat followed by a skim coat.
For all this to be done in 5 days is probably where the problem lies.

 

[Arti]

Av not had a problem re coating with S&C when the 1st coat is still green, but skimming it all before the S&C has cured will always give you issues.................this is one of the main reasons i use renovating plaster. Like bobby says its hasn't dried sufficiently before skimming.

Chances are the skimming will just delaminate from the backing coat.

 

[User___removed]

Av not had a problem re coating with S&C when the 1st coat is still green, but skimming it all before the S&C has cured will always give you issues.................this is one of the main reasons i use renovating plaster. Like bobby says its hasn't dried sufficiently before skimming.

Chances are the skimming will just delaminate from the backing coat.

To true.although some spreads have said they have been skimming render when green for years without issues.
Skim when dry is always how I have done and I'm sure most spreads would do the same

 

[Psk]

Thanks for all the replies. The plasterer has returned and is hacking off the affected areas, re rendering, allowing to dry and then will do scratch coats and a re skim. His opinion is much the same as most peoples here, that it should never have been attempted to do the whole lot in 5 days, however the damp proofing company were insistent that that's what should happen. I guess they are happy to take their chances and hope it works out OK, which it hasn't this time!

 

[User___removed]

It's poor there thinking it's ok.feel sorry for the next customer

 

[adapt]

We all have our own ways of working, I did for a long time mainly use S&C and float it up then skim, now I tend to get a good S&C scratch and dub out as needed with SBR in the mix, then put a float coat of renovating plaster on, no messing about with sliding etc.
A lot of the walls I do now if its patch work I tend to plasprime the existing and re-skim the whole wall, a patch will always be a patch

 

[cowen70]

I've recently done this and its all very well and good for them to say they've damp proofed it but did they tank the walls with cement? Otherwise the damp that is still present after the damping has been done is going to lift the plaster and bond off the wall (exactly what happened to me before I started training and was completely bloody clueless) and if huge cracks have appeared its a bad job and a thin reskim over the top isn't going to help you in my fairly novice opinion.

I certainly wouldn't be paying for it. And what I have further learned on these forums is that you are looking at 2-10 months drying time once it has been properly tanked before you can put anything but a matt paint on it.

 

[seanlar]

Hi

We have recently had fairly extensive damp proofing on the ground floor of our house. In one area adjacent to the stair case only part of the wall was treated, with the original plaster and render removed, some dubbing out and damp proofing substances applied and the area reskimmed. This are borders onto the original plaster which was unaffected.

We've had a succession of problems, starting with large cracks in virtually all areas. The weather was very hot at the time the work was done and we understand that this was due to the large volumes of sand/cement and plaster applied in a short time. The contractor has filled most of the large crack which seems to have worked fine, however in the staircase area the plaster was also blown.

In this area the contractor returned, applied a retaining tape to the largest cracks, and reskimmed. Now this has dried there is some minor, but still in need of fixing, cracking returned, and also several hollow sounding areas around the border between the new plaster and old. The contractor has now become quite unhelpful and insists these area are not a problem, and that the hollow sounding areas do not indicate blown plaster, or should be of concern.

I'm not a professional plasterer of course, however I've had much plastering done on several properties, and at no time had any problems like this. I don't feel like it is fine for there to be these hollow sounding areas, or for this part of the job to be "as good as we can get it" in the contractors words.

They are sending out the plasterer again to have another look, however he has told us he is sub contracted by them, and isn't being paid to make these remedial repairs, which makes me suspected he is not going to want to spend any time carrying out further remedial work, and may well follow their opinion that there is no problem.

Any advice gratefully received, the contractor is a member of several trade bodies, however I'm not at the point of contacting them yet (they state I should go through a the contractors formal complaints procedure first, which I'm happy to do if necessary).

How olds your house ?