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Refurbishing Plaster Skim Coat

Our 50 yo c/d grade ranch house is finished inside with rock lath and a verrry thin (1/16 to 1/8 thick) plaster skim coat. The skim coat is full of hairline cracks, in some paces every few inches. On some surfaces, the stuff is loose, and probably needs to be removed.

I believe the best way to fix this would just be to drywall over it, however we have little time to do the work, and having it done is prohibitive.

In researching plaster repairs I've seen that in some cases the setting type compound is recommended for a skim coat. As it stands now, this would be the preferred material, as it is sandable. However, I have not seen any articles specifically pertaining to repairing the cheapo skim that coat we have.

What I wish to accomplish is a quick repair to skim over the areas having hairline cracks, feather it out nicely, and fill in some of the areas where it had been repaired before that remain a little low, so that once it is painted, it looks smooth, and I don't feel nauseous when I look at the walls anymore. :eek: And I'd like it to last a few years.

So currently the questions are,

Anyone done this before?
Is the sack-o-stuff from HD any good (sheetrock brand setting type)?
What is a recommended thickness of application? Can we get away with 1/32 or less (to allow feathering out)?
Any thoughts on roughing up the cracked areas with a disk prior to application? (Yes I've done body work before):p
What about a bonding agent? (It's going over the paint)
Anything else to beware of?
Want to blast through this and get it done with minimal hassles.:D

Thanks for the advice

Hank Bauer
Re: Refurbishing Plaster Skim Coat

Option # 1
Remove any loose or detached finish coat.
Than use a product called Master of Plaster skim one coat of base when dry skim the second coat of base you may be able to trowel this as smooth as most plaster finishes if you want it very smooth use the finish coat of Master of Plaster.
This product does not require a bonding agent and is a very good plaster finish Total thickness of all three coats will not exceed 3/32 to 1/8 inches max.

Option # 2
Apply a bonding agent and skim with USG Diamond Finish plaster This will be cheaper but not as user friendly as the MOP.

Option # 3
Not reccomended by this plaster.
Use a setting compound and skim smooth.
I don't think these compounds are manufactured to skim over PLASTER.
They will work for some length of time but will be affected by moisture changes within the plaster this moisture causing the compound to delaminate from the plaster this process will take time How much time is the big question? Could take 5 to 20 years.

Re: Refurbishing Plaster Skim Coat

Thanks for the reply, Hank.

How do the MOP & USG materials you speak of take to sanding. I never did plaster. I've done drywall, and can smear it on very smooth but still need to sand a little.

Is Plaster easy to work smooth if you have the basic skill with drywall compound. If so, I may not actually need to sand it however would like to have that option in case I do make a mess.


Hank Bauer
Re: Refurbishing Plaster Skim Coat

If you elect to use the M O P you will not have to sand it.
You can use most any type trowel.
If you have the basic skills to do dry-wall this product will be a snap to use.
The only thing required besides the trowel is a spray bottle for misting the plaster to trowel smooth.
I would start with a 4 inch by 11 inch plaster trowel if posible use a stainless steel one this will not leave black marks in the finish coat.

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