Pros: Caulk-gun compatible, textured, permanently flexible, paintable, sticks to virtually any surface, needs no priming
Cons: Somewhat skimpy instructions on packaging
Before painting and waterproofing the east & west facing stucco walls of our home it was necessary to identify and fill anything larger than hairline cracks in the stucco. The Valspar Duramax Exterior Paint I was using does an excellent job at filling hairline cracks, but once cracks get to the 1/8th inch size a filler at minimum is needed to seal the stucco surface.
CRL Vulkem 116 Polyurethane Sealant
For years I’ve used a Vulkem 116 Polyurethane Sealant for all sorts of masonry repairs. Long before I had to deal with stucco surfaces, I used Vulkem 116 Polyurethane Sealants to fill settlement cracks in concrete blocks and concrete foundations. The permanently flexible properties of this sealant make it ideal for handling the effects of freeze/thaw cycles. But of course down here in South Florida freeze/thaw cycles have more relevance in personal relationships than they do in masonry matters, so let’s consider stucco.
CRL Vulkem 116 Sealant is a one-part moisture curing, gun grade polyurethane sealant. It has a grainy texture that is easily tooled to blend in with the texture of the stucco being patched. The sealant consistency is just soft enough coming out of the caulking gun that it can be shot directly into cracks as small as 1/8” without requiring me to chisel out the cracks as I might need to when working with actual stucco cement. This is a huge time-saver. Working with a small spade trowel or even a putty knife I can produce just the right texture so that once the patch is over-painted, it is all but invisible to anyone other than me.
I feel comfortable using CRL Vulkem 116 Sealant on cracks up to about ½” wide with a single application. That’s a pretty big crack. In order to fill cracks this wide, I simply snip the tube nozzle a little further down to increase its diameter and then just slow down the speed of the caulking gun while I’m moving it along the crack. On occasion I’ve even filled golf ball sized holes successfully with this sealant.
Curing Time & Over-painting
All brands of Vulkem 116 Sealant are considered industrial products. The consumer gets very little beyond the simplest instructions for use. From my own experience I find that Vulkem 116 Sealant remains tacky for about 24 hours for most common repairs. I allow it a full 72 hours for curing before over-painting. No primer need be applied before painting. Clean-up with mineral spirits.
This Vulkem 116 Sealant by CR Laurence is tan in color, so it isn’t terribly noticeable on the tan Mediterranean stucco walls. But still, an over-coat was obviously in order. Vulkem 116 Sealant is available in several common colors.
CRL Vulkem 116 Polyurethane Sealant is a versatile and durable sealant easily applied by homeowners with even minimal fix-it skills. I recommend it.