Why Is Fairy Liquid Banned in Mortar?
Using Fairy Liquid—or any dish soap—as a mortar additive is strongly discouraged. While some DIY tips online claim soap makes mortar creamier, the chemicals can weaken bonds and cause excessive air entrainment. In Kansas City construction, where freeze–thaw cycles are common, that’s a recipe for early failure.
Why People Used It discover moreBefore modern plasticizers, some masons added small amounts of detergent to improve workability. The surfactants trapped visit this page air, making mortar easier to continue reading spread—but also reduced strength and durability.
Why It’s a Problem Inconsistent air content: Too much air leads to weak, porous joints. Chemical contamination: Soap residue can prevent cement hydration. Durability issues: Freeze–thaw cycles in Kansas City expand these air pockets, causing cracking and flaking. Proper Alternatives Commercial plasticizers: Designed to improve workability safely without weakening mortar. Air-entraining agents: Precisely measured for cold-weather performance. Hydration stabilizers: Maintain consistency without chemical damage. KC Masonry TipAlways use ASTM-approved admixtures sourced from local suppliers familiar with KC’s temperature ranges. They ensure mortar remains durable through hot summers and freezing winters.
Bottom LineFairy Liquid isn’t banned by law—it’s just a poor choice. Modern admixtures outperform it safely. In Kansas City’s variable weather, professional-grade plasticizers protect mortar strength and longevity.
