Paint removal using soda blasting off of soft brick is damaging the brick exterior
Thanks for all the informative info on this site. I’m owner of a 100-year-old former wagon factory built with soft brick – known in Wisconsin as Cream City brick which is notoriously soft.
The previous owner had painted the building many times. As discussed, trapped moisture in the brick causing spalling, etc. Right now we are trying to gently remove the paint using a soda blaster. Soda blasting is supposed to be one of the gentlest of methods of paint removal. However, due to the very strong bond that the old lead paint has on the soft brick, even soda blasting is damaging the brick’s exterior hard finish.
I’d like to continue removing the paint as the project was originally intended so as to expose the original historic look, but I’m concerned about the damage being done to the brick. One thought I had was to finish the tedious paint removal and then spray a water repellent on the brick exterior which is not supposed to deter the brick’s ability to dry itself and hopefully stall the weathering that would surely attack the damaged brick.
I’m just writing for input as to whether to continue blasting the paint off with the knowledge that the brick face is being damaged or if you perhaps know of a better solution to my dilemma. Thanks much for the help.
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Replies
As messy as it is to work with, sodium hydroxide (lye) based paint removers are about as easy on the brick as you'll be able to do. Mechanical methods will all have the bonding issue. I once saw a ~150 year old multi-story brick building in Brooklyn NY with dozen odd coats of paint successfully stripped with a lye paste- probably a version Peel Away (tm). They were using plastic scrapers and a hose, not a pressure washer, though that might be quicker, if a bit messier- catching and properly disposing of the lead contaminated caustic crud can be an issue.
Here's a video of a small job being painstakingly done by a homeowner. For larger projects you'd slather it on thick, give it a day or so of soak, then get as much off as you can with large scrapers first:
https://www.youtube.com/watch?v=0fj3W2otrs0
It's definitely slower than blasting, but it does a great job of preserving the integrity of soft substrates.
I can second Dana's suggestion of Peel Away. I've used it on wood, stone and brick with good success. It can be time consuming to get all the nooks and crannies. I was working inside so a pressure washer wasn't and option, but outside it might be if you can capture the lead contaminated runoff.
Peel away