Sikaflex Single Component Polyurethane Sealant


Best construction sealant

It was probably in the early 1980s I first used this caulking/sealant/adhesive. I have tried other brands of polyurethane sealants and always regretted not having spent an extra dollar or two on Sikaflex. I have never seen a failure of this sealant, even if applied outdoors, exposed to the elements for many years. It’s adhesive properties are amazing. If you put something together with this, it isn’t coming apart. This is truly a lifetime caulking. Not like that water based modified silicone whatever junk.

It isn’t the easiest thing to apply, it tends to string out at the end of the bead – my friend in the industry calls that “having legs.” It can be smoothed out considerably, the best I’ve found for that purpose is WD-40. Wet a finger with WD and it works like a charm. WD also works great for cleanup of this material from hands, caulking gun, whatever.

It comes in a wide variety of colors, Home Depot carries a limited assortment of colors, but the masonry supply place I do business with has them all – at a higher price. This is a moisture curing material. It does have a shelf life if unopened. Seems like a year, maybe two. The biggest downside to it is once the tube is opened, it needs to be used soon. I’ve tried a variety of caulking gun “plugs” and caps and none worked any better than a pencil stuck in the end. And at that you may get it to last a week in cool weather. A similar material is the Sikaflex Self-Leveling sealant. I purchased this by mistake, and it is self leveling. No amount of effort on my part could get it not to flow to level. In the right place that is a good thing. In the wrong place a disaster.

This is an ideal material for using with a pneumatic caulking gun.

-- Norm 01/25/18