Pouring concrete in the rain can compromise its strength, increasing the tendency for dusting and scaling to develop. Once the damage is done, it can be hard to rectify and will often ruin the appearance of the finished surface. Don't let it rain on your parade.

How long after it is poured is concrete safe from rain damage?

If the rain occurs when the concrete is fresh (about 2-4 hours after mixing), the surface should be protected from the rain. If the finishing process was recently completed, rainwater may not cause damage as long as it is not worked into the surface and the slab is left untouched.

What happens if it rains after you pour concrete?

HOW DOES RAIN AFFECT CONCRETE? Rain falling on top of freshly laid concrete can damage the surface and compromise a level and floated finish. Even worse, if too much extra water works its way into the concrete mix, this can result in weak concrete overall.