Protecting concrete during construction - Part 4: How the slab finish can impact the timing & type of concrete protection

Protecting concrete during construction - Part 4: How the slab finish can impact the timing & type of concrete protection

Why are we so concerned with the timing of protection you might ask? ?

Well, it’s because going down too soon with protection can mean prematurely capturing moisture and other contaminants (uncured sealers / curing agents) which are being expelled from the slab. Going down too soon with protection can mean trapping these by-products and thereby creating imperfections on the slab’s surface.

There are many different finishes with concrete, used on both commercial and residential sites. These can include, but are not limited to polished, trowelled, burnished, broom, exposed aggregate, stamped concrete and cove finish. And to add further complexity, the desired aggregate exposure is another variable (e.g., cream, salt & pepper, and high aggregate finish) which should also be considered in conjunction with a slab's finish.

So, what does this really mean and why should I care?

It means finishes, such as, cove-based or broom are more forgiving than others. This is due to the undulation of these surface types, making it more difficult to notice imperfections in the slab. On the other hand, with a polished or steel trowel finish slab, the surface is flat and therefore the reflection of light off the slab is more noticeable to the naked eye. So too with any imperfections. Therefore, the more polished a slab, the more noticeable things are like marks, streaks, cure lines and tiger stripes, which can happen when not protecting the slab correctly.

By waiting longer and giving the slab adequate curing time, you reduce the chance of trapping moisture & contaminants on the surface and within. In broad terms this means - the more polished or refined the surface - the more likely the wait time will extend between pouring and protecting.?

As with our earlier posts, the concrete finish must also be considered in relation to other factors prior to laying down protection, such as weather, duration of protection, slab thickness, sealers, densifiers, curing agents and more.

That’s it for now. Please stay tuned for our next post which will drill into concrete slab thickness – and again why this is important. In the meantime, if you have any questions relating to concrete protection, or this post, please give us a call on 1300-038-244.