A long time ago, I heard about a product called Dexpan. Made by Archer USA, it is a controlled demolition agent used to break stone and reinforced concrete without the mess, noise, and hazards of conventional demolition tools or explosives. My company typically calls a subcontractor to handle larger concrete demo projects, so I never had a chance to try this stuff. Until a few months ago!
A client in Kensington, CA, for whom we were repairing a leaking roof deck, had an old piece of concrete retaining wall sticking out of the ground. It no longer served any structural purpose, so she asked if we could get rid of it. Electric and pneumatic demo hammers work great on foundations, slabs, and other horizontal surfaces, but using them on anything vertical is a pain in the you-know-what. Figuring this was a perfect opportunity to try Dexpan, two containers of it showed up at the job site a few days later.
We used the Bosch 11241 EVS to drill a series of angled holes in the footing and wall, careful not to drill all the way through. Instructions recommend 1-1/2″ diameter holes, but the largest carbide-tipped drill bit we have is 1-1/4″ and we decided to make do. The holes were spaced about 8″ apart and an equal distance from all edges. You have to make sure there is room for the concrete to expand. If it butts up tightly against a structure you want to preserve, a product like Dexpan is not suitable. After the holes were drilled and cleaned, we mixed the Dexpan powder with water as recommended, and poured it in. I wish we had had a funnel on hand to make the pouring a little easier, and I suggest you get one for your project. Next day we were pleasantly surprised to see the results. Check out this quick vid!
If you have used Dexpan (or a similar product) on a recent project, please share the specifics and how it worked out for you.