Polyurethane Caulk – Possibly the Best Sealant
The ultimate sealant could possibly be polyurethane caulk. This is a bold claim, especially with so many types of sealants on the market. This sealant has taken all the best attributes of all other sealant types and put it into a convenient, single component cartridge ready to tackle your most difficult, or even impossible, caulking requirements.
Urethane caulk can be difficult to apply. It has a sticky, putty like, consistency and requires mineral spirits for both tooling and clean up. But, it will cure into a paintable rubber capable of stretching 300% or more. Some manufactures boast as much as 1200% elongation. Plus, it has very high tensile strength. Can adhere to almost all types of surfaces. Including concrete, wood, glass, plastic and metal.
This incredible ability to adhere to so many dissimilar materials is just one of its features. Very important when trying to create a seal between various materials that expand or contract at different rates. Plus, urethane caulk has excellent chemical resistance.
No Mixing or Special Equipment Required
Available in single component cartridges are designed for both standard 10 ounce and 1-quart caulking guns. You have a choice of non-sagging or self-leveling formulas.
- Use the non-sagging formula for expansion joints in concrete block, gaps in wood siding and around windows or doors.
- Self-leveling formulas have a very high resistance to abrasion. A perfect match for control joints in concrete floors, especially garage floors prior to the application of epoxy.
Polyurethane caulk can be applied to very large gaps, 1 inch or more, and not loose its ability to create a perfect seal. I have used Sonneborn NP-1 for years on commercial buildings and garage floors prior to the application of a high performance finish, with perfect results.
Although this sealant is difficult to use and will cost considerably more than standard caulking, the benefits will be worth it in the long run. It’s possible this type of caulking could outlast the paint job and the person who applied it.