Hi, I’m Mark with The Perfect Paver Company, here to answer this week’s question of the week, why do some pavers turn white after being sealed?
So there are two types of sealers. There are breathable sealers and there are non-breathable sealers.
Breathable sealers allow ground moisture to perculate up through the paver and back down through the paver without trapping that process from happening. Non-breathable sealers do the opposite.
So, when you have a non-breathable sealer, you’re essentially trapping ground moisture underneath the sealer and you can develop things like hydrostatic pressure which basically builds up a pressure strong enough to start to lift the coating from the paver and then that space inbetween the paver and the coating fills up with moisture and you basically see condensation and that gives off that white appearance. So, it’s really important to seal your pavers with a breathable sealer.
So, the other reason why pavers can turn white after being sealed is not related to the sealer as much as it’s related to what’s called efflorescence. So, in pavers, there are natural salts. Primarily pavers made from concrete, there are natural salts. We refer to them as efflorescence. When ground moisture or when rain goes down into the paver, those natural salts in the paver stick to that moisture and then when it evaporates back up through the paver, it takes the efflorescence with it and it leaves it on the surface as the moisture evaporates away.
When you have sealers that are not breathable, it can trap that efflorescence in underneath of the sealer. Now, it’s still likely that if you’re experiencing efflorescence, you’re still going to see that regardless of whether or not you have a breathable or non-breathable sealer, but you’re going to see less of it when you have a breathable sealer.
In addition to that, when your pavers are installed over top of a concrete base, there’s nowhere for that water to go when the water drains down through the paver, and hits the concrete base. It kind of get stuck there. So, what happens is the natural salt stick to the moisture in the concrete base as well and it pulls that salt up through the paver and leaves a deposit on the surface.
So, if you have poor drainage, if you have pavers installed on concrete base and you’re seeing white on your pavers in those areas, it’s likely efflorescence and it’s being magnified by drainage issues.
So, I hope that answered your question as to why pavers can turn white when they’ve been sealed and by the way, if you have a question that you would like answered in a future question of the week, please comment below and I would be happy to do so. Thanks again and have a great day!