Lime Plaster Repair and Painting?

Question

OK, my wife and I just bought a new home that had a textured plaster look. We decided that it would look better to smooth the walls, though. So, we prepared to sand the walls down and then apply a skim coat. After working with a small patch of the wall as a test surface, we stumbled onto the original walls. It turns out that at some point somebody else had skimmed to get this textured look. So, I found that I could just scrape the old skim coat off (with some elbow grease) with a sharp trowel. This method ends up leaving the original walls rather pristine. So, my first question:

1.) I think that it is a lime based plaster wall, but am not sure. How can I tell if it is lime or not?

Due to not realizing that this original wall was behind the current wall, I had sanded a little bit into the lime finish. I am now doing a pretty good job of getting the current stuff off without really nicking up the old stuff though. So my second question:

2.) What is the best way to fix the little dings that are created in the original finish by scraping off the current coat? Do I have to get a lime putty, or do I have to do a totally new lime finish?

Now for the final questions:

3.) Once we have smoothed the walls out, we are going to paint them. How long do we have to wait after doing whatever is needed from question 2? If we use a lime plaster to fix, I have read that it will take up to 3 months to set enough to paint.

4.) Also, how would we go about painting this? I have read about needing a layer of emulsion....

Thanks to any experienced plasterer. I know that this is no simple feat, and that is why I am trying to gather as much details as possible to deal with this....

Answer 1

OK  first start by cleaning the walls of any residue or chalky powder.

Go to home Depot and they have a product called Durabond that sets at different rates 5, 20, 45, 90 minutes (I recommend using the 45 if you are inexperienced with using the product)you need to mix it with water and it has a small shrinkage rate.

when you patch these nicks use a 6" taping knife that you can also purchase at Home Depot and while your at it buy a plastic taping pan sold in the same location they are red pans about 4" x4" x14" this will enable you to make small batches of this material and it will clean out of the pan very nice.

When you apply the Durabond go across the length of the nick and scrape clean the remaining material so you will have less sanding when it dries.

This may take 2 or 3 application depending on the depth of the nick.

When you complete the patching of all the nicks on one wall you will be ready to sand it.

Home Depot also sells hand held manual sanders or pole sanders sold in the same location as the other materials above.

Buy the sanding screens prefitted  that fit these sanders 120grit.

Sand the whole wall not just the patches.

Followed by the application of a enamel undercoater latex that is also sold at Home Depot as your primer (it will put a small stipple on the wall) to make the surface uniform between the patches and the existing smooth wall. If you have any other questions email me at [e-mail]

General Contractor and Painter for over 25 years