DEAR TIM: I have a 1938 Cape Cod stone house with a behemoth laundry sink in the basement. It appears to be made of concrete, soap stone or something similar and has two giant tubs. It’s supported by a steel stand that’s in pretty good shape with some minor rust. Can you identify it? How long have these sinks been around? How can I clean and restore it? Also, the faucet holes aren’t standard size or distance can I fill and drill new ones? Chris R., Lexington, KY
DEAR CHRIS: You bet I can identify it. Among other things, I’m a master plumber and I’ve owned and moved several of these monster sinks. Believe it or not, you’re the proud owner of a collector’s item. You’ve got a marvelous precast concrete laundry tub that’s nearly indestructible.
My research shows the first generation of these wonderful sinks was displayed for the world to see at the 1867 Paris Exposition. A man by the name of Joseph Monier was a gardener who started making steel-reinforced concrete tubs and pots because he was dissatisfied with clay and wood pots that would fall apart.
Concrete is strong when you try to compress it, but if you try to stretch or bend it, it’s weak. Steel is exceptionally strong if you try to stretch it. When you combine the concrete and steel in the right configuration, you can make beams, columns, suspended slabs, bridges, boats, and even laundry tubs!
I was lucky enough to have concrete laundry tubs in the first two houses I owned. As you might imagine, they came in different models with one, two or three sink basins. The sinks weigh hundreds and hundreds of pounds.
I believe the reason they’re so strong is because the manufacturers decided to make the concrete mix quite rich. They added enough Portland cement so the concrete probably tested out at 6,000 pounds per square inch or higher compressive strength. Years ago when the sinks were made this extra cement, probably only cost the manufacturers a nickel since there’s not that much cement volume in each sink. What a wise decision it was!
The top lip of these sinks is made from steel so the edge won’t chip. The workmanship that went into creating each of these sinks is of the highest quality. I’ve seen hundreds of these sinks in my career and all of them are impressive.
I would start the restoration process by removing any rust from the steel support stand. Once the stand is sanded and ready for primer and paint, use a high-quality paint made to paint steel. The stand probably was painted black when the sink was new. It could have been a dark gray as well.
After you have the steel stand looking good, then start to remove any paint from the inside of the sink basin walls. You can do this with common paste paint strippers. Follow the directions on the label and be sure the space is well ventilated if you’re using a stripper that contains methylene chloride.
I would then try to scrub the sides of the sink with a common abrasive cleaner that you can get in any grocery store in the cleaning products aisle. Just test it on a small area at first using a scrub brush with stiff nylon bristles. Do not use a wire brush of any type, especially one on a spinning power tool. That will damage the concrete surface in no time.
You’ll have fantastic results removing oil stains and any organic stains using a powerful oxygen bleach solution. Just spritz the sides of the sink with the solution keeping the concrete wet for an hour or more. Don’t let the solution dry. Every fifteen minutes, scrub with the brush and see if you’re making progress. If so, keep at it until you get the sink clean.
Realize if you use muriatic acid to try to clean the sink, you’ll damage the steel lip and you’ll erode some of the cement paste that makes the inside of the sink basins so smooth. I’d not recommend using acid at all.
If you want to drill new holes that will work for a modern faucet, you can do this with a diamond hole-cutting saw. Realize you’ll have to make certain the blade can cut through tiny steel wire that you’re sure to encounter in the concrete matrix.
Before you do this radical modification to the sink, please consider taking the time to visit plumbing supply houses where plumbers purchase most of their products. These unique businesses can be found in just about every large or medium city. They rarely advertise, but believe me they exist.
There’s a great chance these supply houses will have a faucet that will work using the existing holes in the sink.
If that doesn’t work, I’d be inclined to work with a local welder who works in stainless steel. See if he can’t fabricate a mount that has holes for modern faucets. This mount would have small bolts that would allow you to use the existing holes to pull the mount tight to the sink and leave enough space for the water supply lines to feed the faucet.