Planning on a coating for your concrete floor? If you are expanding or renovating your facility and have laid down new areas of concrete slab, you may hear both the concrete contractors and the painting contractors invoke the 28 day rule.
The products used to paint or coat concrete need a clean, dry surface to create a strong protective coating. However, concrete requires a carefully controlled amount of water to be present in the mix in order to cure properly. This process is called hydration, and is a chemical reaction between the cement, aggregates and water.
Although a great deal of the hydration in a typical slab of concrete is complete in the first seven days, the chemical process continues on at a much slower rate. Hydration takes place in concrete for years, making a properly poured slab stronger and stronger over time. However, the bulk of the hydration process is complete in just under a month. Since waiting years to coat a new slab would be impractical, your painting and coating contractor will wait 28 days before applying product to your new concrete floor.
If you require your contractor to paint the concrete before the hydration process is complete, the water present in the microscopic spaces of the concrete will seriously degrade the strength and appearance of the paint. The coating will be more prone to wear and tear damage and will blister more readily, cutting the lifespan of the paint and ultimately costing you more money.
Coming Up: The 28 Day Rule Strikes Again