Properly priming the slab before skimming.

by Ethan Schneider

Recently there has been some discussion about priming the slab before skim coating. To clarify this issue it is important to understand why we prime the slab after it has been properly prepped and before we skim.

On exterior applications we prime the slab with a mist of water to dampen the slab just prior to skimming. Doing this serves two main purposes.

1.Priming with water slows the absorbtion rate down so that the modifier has more time to penetrate into the pours of the concrete thus creating a better bond.

2. By slowing down the absobtion rate, it makes it easier to trowel the skim mix because it stays wetter longer. If we did not prime the slab before we skimmed then the slab would hydrate itself by absorbing the modier directly out of our skim mix causing the mix to tighten up faster.

It is important to to remember that we want to skim over a damp slab not a wet slab. We do not want to skim over standing or pooled water. The slab should appear darker because it is damp not shiny because it is wet.

There are specific situations when we may describe priming with modifier or not priming at all particularly on indoor projects or in colder climates. Please consult with the CTI technical department to determine the best procedure for the specific project.

• Tell customers they should expect a card in

the mail in about two years to schedule a light

power wash and more than likely, another

coat of sealer.

Please explain that if they do not call

or return the card you will not call

them to schedule this appointment.

Those warranty calls are great selling

opportunities for other areas of their