Saturday, April 9, 2016

Sealers - what you need to know

It is that time of year once again! Pressure wash that driveway, patio and sidewalk. But dont stop there, and forget to seal it afterwards. Why go through all the work then leave that clean exposed aggregate or concrete unprotected? That exposed surface is now more-vulnerable than when the oil and dirt were on it. But what sealer is best?  There are a couple things to consider. Looks and longevity are usually at the top of the list. What most people dont know is that most who want that nice shiny sheen on their exposed  aggregate sacrifice longevity. There is no way around it. In order to get that look, acrylics are used in the mixture. Acrylics are not sealers! Acrylics are coatings. The Difference between a coating and a sealer is the penetration they have to the surface. Acrylics have either a water or solvent base as a carrier. The thinner the mix or percentage of acrylic to the carrier the more penetration it has. Acrylics need a build up on the surface to create the sheen. 25-30% acrylic is typically standard to achieve that desired result. So everything is coated and looks great, but the catch is coming. In Oregon and high moisture, rain fall or humidity states, moisture gets trapped underneath these coatings. Coatings do not breath and trap thst moisture. The result is white haze, premature failure, flaking an chipping in some extreme cases. The fixes are only temporary at best. The coatings also need to be re freshed every couple years to maintain the desired shine as well. This is evident by areas that are less exposed to the elements under the eves and shaded areas.
Sealers on the other hand, penetrate into the pores and create a vapor type barrier but allows moisture to escape, depending on the carrier types. You can even attain a moderate sheen but nothing like acrylic coatings. The sealers also come solvent and water based as well and have a much longer wear life if they are not just topical in nature. Coatings and sealers both have their place. It is good to understand the pros and cons of each before making a decision...