A retired mason in Boise told me he always adds a half cup of dish soap to his mortar mix on hot days.

He said it slows the set just enough to keep it workable, which saved my bacon on a 90-degree patio job yesterday, but has anyone else tried this trick or is it just an old wives' tale?

3 comments

3 Comments

hugo_robinson2528d ago

My uncle tried the dish soap trick on a chimney repair in Phoenix. It made the mortar foam up and lose strength, bricks started shifting within a year. For hot weather, we just use cold mixing water and keep the mortar in the shade. Retarder additives from the supply house are made for this, soap can really mess with the bond.

elizabethg8528d ago

Got to disagree here, hugo_robinson25. A little bit of dish soap works fine as a plasticizer if you know what you're doing. The key is using a tiny amount, like a teaspoon per batch, not just squirting it in. Your uncle's mix probably foamed up because he used too much. Plenty of old school masons I've worked with swear by it in a pinch when it's hot and you need more working time. The store-bought retarder is definitely the right call, but saying soap always ruins the bond is a stretch.

fiona98528d ago

Honestly, that half cup amount sounds insane, like a recipe for total failure. Elizabeth's right about the tiny amount, but even then, you're playing with fire. Soap breaks the surface tension of the water and can leave a film that wrecks the bond long term. Just spend the few bucks on actual retarder, it's not worth risking your work.