12 April, 2008

Removing Paint from Concrete, Masonry, Limestone

I have a hard time sitting still without getting antsy. I think it's because I work for myself, so time spent not working on a project is time spent not making any money. When I'm not on the computer, I feel I should still be doing something somewhat useful and not just sitting around and relaxing. Ted's much the same way.

A few days ago, when the weather was in the sixties, I whined until I got Mom and Ted to sit with me on the front steps to enjoy a cup of coffee and watch the world go by. The picture below was taken in winter, but that's pretty much what the front entrance looks like now, just without snow.

But did any of us sit still? No. I'm pacing back and forth in front of the house, coffee in hand, discussing plans for the garden with Mom. Ted was sitting on the porch in the shade, but in between sips of coffee he's working on this:

Scraping off flaky white paint. (What's the matter with us? Why can't we just relax?)

The previous owners had coated everything they could in white paint prior to selling. The interior walls had a fresh coat and I think the same paint--interior paint--was used to paint over all of the decorative masonry on the exterior. If you look at the top photo, you can see that all of the window sills and all of the horizontal trim has been painted white.

You can tell better in this photo (from the original listing):

So those little squares at the top, those long horizontal decorative bits that wrap around the house, and every window sill has been painted white.

Only, I'm pretty sure it's the same interior paint used on the walls. The flat surfaces are mostly peeling and flaking, and I don't recall them doing that last fall when we first saw the place. Winter was harsh on them. It's very easy to get the paint off these surfaces with a scraper, and as Ted removed the paint, we saw that the surfaces are actually dirty, and in some spots there is green algae, or whatever it is that grows on limestone. So the paint doesn't have a firm grip. At least not on the horizontals.

Ted made some decent progress that day, and every nice day we've had since I've been out there with my cup of coffee. I have most of the flat surfaces by the front steps now clear of paint. But I still have the vertical surfaces to do, and I'm encountering quite a bit of trouble. The stuff is not flaking nearly as much, and in some parts, it's quite stubborn. I'm afraid of scraping too hard.

I was hoping not to have to go the chemical route, but I think a trip to Sherwin Williams or Home Depot might be in order. I had tried a soy-based paint remover on some of the interior brickwork, but without success. Although I've heard a few good things about PeelAway 7 and its use on masonry, I haven't personally encountered anyone who has tried it for such. I tried PeelAway 6 on some woodwork with mixed success--it's okay on latex, but has problems with enamel. Is there really that big a difference between the 6 & 7? I haven't been able to locate the PA7 locally, and it's pretty expensive online, so I'd like to know more about it before making the investment.

So, does anyone have a recommendation for removing paint on masonry? Have you been able to remove paint from similar surfaces?

Update: My apologies to Dynochick; I originally called all of the decorative trim concrete, when it fact some if not all is probably limestone. I was not aware of just how different the care of both materials are, and carelessly mixed terms. Sorry that my post led you astray.

Before heading out to the paint store for PeelAway7, I decided to check for some coupons online and found one on another blog for 20% off at Sherwin Williams. I'll give it a try this week. Hope it's a valid one.


Jan Marie said...

Sand blasting. One layer of paint would come off in a flash.

With a little planning (extra ladders/people) I bet you could blast all the window sills etc in one weekend.

You'll also need to rent an air compressor that can handle the volumne of air needed to run a sand blaster.

Use play sand. It's cheap and any that gets on the ground is no big deal. Use tarps if you are going to plant any edible plants in the area and might be worried about lead content. If you use tarps you can recycle the sand back into the hopper.

If you rent a sand blaster and have metal patio furniture that is rusty, blast that at the same time.

Pressure washing is another option but I have never found it as effective and you always run the risk of getting water where you don't want it.

Good luck.

Jocelyn said...

I would worry that sandblasting might damage it. Limestone is a softer stone. My first thought was a power washer. That combined with peelaway sounds like a good approach to me.

I hate when people limestone white!

Steve said...

I would be VERY careful--not to screw up your building. I ran a quick check on Google, "paint removal limestone" and you'll see a library full of information. Powerwashing at more than 100psi can cause damage, sandblasting out of the question. Looks like chemicals is the way to go. My guess is it will take quite some time and be messy.

We had a mason come by and tuckpoint our building and asked him to clean up a limestone lintel while there, and to our horror, he skim coated it with concrete. Now the only way to bring it back to original is total replacement of a lintel measuring 24" x 84". Very costly and disappointing.

So I would research and test and not rush into anything or else you may have to live with it FOREVER!

Joanne said...

Thanks for the feedback. I ended up Googling the subject as well, because I am so paranoid about doing anything wrong and have discovered that the limestone is easy to scratch if too much force is used. I found some good information with the Chicago Historic Bungalow Initiative. They published a PDF on paint removal techniques with some good advice on techniques.

Joanne said...

After more research, I think the bulk of the paint will have to wait to be stripped off. There are far more pressing projects we need to tackle. We'll finish up with the limestone on the front entrance, as that had the worst of the peeling paint, and get that looking less shabby overall. But that's probably it for now.

Jan Marie said...

The post said concrete and masonry, nothing about limestone.

Joanne said...

Dynochick/Jan--Sorry, that was my fault. I was calling it all concrete and masonry; we seem to have a mix of materials in The Box House, with our basement being half brick/half concrete, for example.

I was thinking that the bulk of the exterior features were concrete, but it wasn't until after Jocelyn mentioned limestone that I thought, yeah, probably, and went to update the post (neglecting to update the commentary here.) I still can't tell what it all is, as the paint is coating everything.

I might look into sand blasting for the sidewalks around the garage, as that's definitely concrete, and the front walkways as well.

Jennifer said...

Well, limestone IS nature's cement... it's basically cement. My father-in-law is a stone cutter that works almost exclusively in limestone.

My husband worked at the shop for a while and has lots of experience... he recommends either sanding it down or this cleaner called K2R http://www.k2rbrands.com/... he said it's pretty awful (strong) stuff, but it really gets oils out of stone.

Jennifer said...

A clarification... he says sanding is the best first course of action, and the easiest. Limestone is soft...

Anonymous said...

Based on the above sanding tip I have just brought my yorkshire stone cold slab in my Edwardian house back to its original stony glory. Many thanks.

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