Methods to assess condition of plaster?

nedc

New Member
Hi all,

Three months ago, I had walls re-plastered and painted by a plaster/paint company. The walls which were taken down to the brick and built back up are fine - no problems. But the walls which were "spot" plastered (plastered where needed) are now showing large spider cracks (2mm). The plaster used throughout is a mineral plaster render from Keim.
The contractor claims: 1) his workers did their job and removed the old plaster and that any old plaster that was not removed falls into the "unforeseen" issue category and is the owner's responsibility. 2) the Keim plaster render reacted with the old plaster and caused it to weaken and fall away from the brick wall (the contractor is blaming the Keim product)
Another contractor looked at the walls. This contractor believes that not enough of the old plaster was removed from the walls before the new plaster was applied, and that the new plaster was not able to fix itself to a sound surface area.

The photo shows a cracked area that the 2nd contractor dug out. The old plaster is dry and crumbles very easily.

The contractor claims there is "no way to know if plaster is old" before new plaster is applied.
My question: What methods are use by professional plasterers to assess the condition of plaster on a wall and determine if it needs a full renovation or just spot plastering?
 

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Hi,
The Keim mineral plaster was used as a preventive measure against dampness. It's a small room (10x10feet) and previously and older couple lived there and never opened a window. There was some visible black mold (less than a square foot in size) but it was located father away in a bottom corner of the room and it was easily taken care of. The darker, tan-colored plaster is the old plaster and it is quite dry and sandy, crumbling easily.
 
Hi all,

Three months ago, I had walls re-plastered and painted by a plaster/paint company. The walls which were taken down to the brick and built back up are fine - no problems. But the walls which were "spot" plastered (plastered where needed) are now showing large spider cracks (2mm). The plaster used throughout is a mineral plaster render from Keim.
The contractor claims: 1) his workers did their job and removed the old plaster and that any old plaster that was not removed falls into the "unforeseen" issue category and is the owner's responsibility. 2) the Keim plaster render reacted with the old plaster and caused it to weaken and fall away from the brick wall (the contractor is blaming the Keim product)
Another contractor looked at the walls. This contractor believes that not enough of the old plaster was removed from the walls before the new plaster was applied, and that the new plaster was not able to fix itself to a sound surface area.

The photo shows a cracked area that the 2nd contractor dug out. The old plaster is dry and crumbles very easily.

The contractor claims there is "no way to know if plaster is old" before new plaster is applied.
My question: What methods are use by professional plasterers to assess the condition of plaster on a wall and determine if it needs a full renovation or just spot plastering?
You in the USA?
 
Look feel prod.
I use that method for almost everything.
Thanks!
How deep into the plaster would you do these things? (my contractor says the old plaster "was hidden beneath good plaster" and that "no one would have been able to detect it")
Would you be looking at the particular characteristics of the plaster? (dry, sandy, etc.?) Or how it adheres to the wall?

I have no issue with paying someone to do the job right, but it seems that there is now more work required to open up the wall and start over than if it had been done properly.
 
Thanks!
How deep into the plaster would you do these things? (my contractor says the old plaster "was hidden beneath good plaster" and that "no one would have been able to detect it")
Would you be looking at the particular characteristics of the plaster? (dry, sandy, etc.?) Or how it adheres to the wall?

I have no issue with paying someone to do the job right, but it seems that there is now more work required to open up the wall and start over than if it had been done properly.

Did he do the works himself? If not he is talking bollox...basically he chucked his lads on it 'get it done' and they didn't prepare it properly. If you are going over the old then unless you can be 100% sure it is sound then it is good practice to fully mesh the render/plaster.

From the photo it looks like the new plaster is putting stress on the weak background.

Have you paid fully?
 
Hi FreeD,
Thanks for the feedback!

The contractor didn't do the work himself, his plaster workers did the work and I think the contractor did not check up on their work. I think you may be correct that the workers did not check the old plaster and didn't do it properly. We also had new electrical lines installed where old ones were and the walls were opened up. Some of the cracks follow these electrical lines. My point being that the plasters had the opportunity to see the state of the plaster deep inside the wall where the electrical lines run.
So far, we only paid for the new ceilings that were put in. For the walls, we wrote a letter to the contractor saying we are making a claim under law.
We now have a certified architect, who agrees with your assessment, and we just saw a lawyer who specialize in building construction (who also sees it as the contractor's problem.)

Solutions? Would it be possible to carve out the old plaster and fill the cracks? Make a 20-30 cm wide gap and apply plaster and mesh over it? Or would we need to put larger sheets of mesh on the wall to hold the new - and old - plaster in place?

Thanks again!
 
A solution was proposed today: the contractor is willing to repair the cracks in the walls using a fiber-glass mesh with plaster. In the room with a lot of cracks, this means covering most of the wall with mesh and plastering over it.
Any thoughts on how well this will work?
 
A solution was proposed today: the contractor is willing to repair the cracks in the walls using a fiber-glass mesh with plaster. In the room with a lot of cracks, this means covering most of the wall with mesh and plastering over it.
Any thoughts on how well this will work?
Its a bodge, the only way to do a proper job especially if your some c**t who gets lawyers involved is to start afresh, that means taking the walls down and renewing all blockwork or plasterboard to give a good background for new plaster.
 
Its a bodge, the only way to do a proper job especially if your some c**t who gets lawyers involved is to start afresh, that means taking the walls down and renewing all blockwork or plasterboard to give a good background for new plaster.
Not what I want to hear, but it makes sense.
On the bright side of things, we're not moved in to the place yet - mainly because the contractor took his sweet time - and we haven't paid him anything. Giddy-up,'cause I already got lawyered-up.
Thanks for the feedback!
 
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