Caulking & waterproofing
Urethane caulking in San Diego
The right sealant for joints that will be painted over or covered with an elastomeric coating.
When we recommend urethane
- Joints that will be painted
- Joints under an elastomeric coating
- Joints already caulked with urethane
Overview
A paintable sealant that works with coatings
When joints are going to be painted over or covered with an elastomeric coating, we usually recommend caulking them with urethane. Urethane sealants work well with acrylic and urethane paints and coatings.
Urethane is also easy to apply to joints that already have urethane caulking, and it can save money compared with silicone.
The trade-off is durability in the sun. Urethane caulking breaks down faster under UV light, and in general it does not last as long as silicone. For exposed joints that will not be coated, we usually suggest silicone caulking.
Service at a glance
- Best for
- Joints that will be painted over or covered with an elastomeric coating
- Usual alternative
- Silicone caulking, for exposed joints that will not be coated
- Service family
- Concrete Caulking/Waterproofing
Where it fits
Joints where urethane makes sense
Urethane is the sealant for joints that will disappear under paint or a wall coating. It also suits joints that were caulked with urethane before.
Joints that will be painted
Urethane accepts acrylic and urethane paints, so the joint can be painted to match the wall around it.
Under elastomeric coatings
Joints sealed before an elastomeric wall coating is applied work with the coating that goes over them.
Existing urethane joints
Joints that already have urethane caulking are easy to recaulk with urethane, which can keep costs down.
Trade-offs
Urethane caulking at a glance
Strengths
- Paintable
- Compatible with acrylic and urethane paints and coatings
- Easy to apply over existing urethane joints
- Lower cost than silicone
Limitations
- Breaks down faster under UV light
- Shorter life expectancy than silicone
Planning a urethane joint
Coatings, sun exposure and substrates
Three questions shape a urethane joint: what will go over it, how much sun it gets, and what it is bonding to.
Paint and coatings
Urethane is usually the sealant of choice when an elastomeric wall coating or paint will cover the joint, because it works well with acrylic and urethane paints and coatings. A coating over the joint also shields the urethane from direct sun.
Exposure and substrates
- Exposed joints in full sun break down faster with urethane, and white urethane can yellow with UV exposure
- Urethane has more limited temperature resistance than silicone
- Some substrates, such as vinyl, need a primer before urethane is applied
- The new sealant has to be compatible with any sealant already in or next to the joint
Before recaulking
Preparing a joint for urethane
Preparation depends on what is in the joint now and the condition of its edges. The goal is a clean, sound surface that the new urethane can bond to.
The old joint
Cracked, delaminated or failed sealant is removed, and the joint is cleaned of loose material, grease and dust. Where the old caulking is urethane, recaulking with urethane keeps the materials compatible. If the joint had silicone, it has to be removed completely, because only silicone sticks to silicone.
Edges and repairs
Chipped or broken joint edges in concrete or masonry are repaired before the joint is sealed, because sealant cannot bond to a crumbling edge. Sealant work does not repair the concrete itself. See concrete repair.
FAQ
Urethane caulking questions
Why is urethane used under elastomeric wall coatings?
Urethane works well with acrylic and urethane paints and coatings, so it suits joints that will be covered by an elastomeric coating, while silicone cannot be painted.
Does urethane caulking need a primer?
Sometimes. Some substrates, such as vinyl, need priming before urethane is applied. Whether a primer is needed depends on the substrate and the product.
Why would a white urethane joint change color?
White urethane can yellow with UV exposure. On exposed joints that will not be painted, silicone is usually suggested instead.
Can urethane be used where the old caulking was urethane?
Yes. Urethane is easy to apply to joints that already have urethane caulking, once the failed sealant is removed and the joint is cleaned.
Areas served
Serving homes and businesses across Southern California
- San Diego County
- Orange County
- Riverside County
- Los Angeles County
Free estimate
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- Southern CaliforniaSan Diego, Orange, Riverside & Los Angeles counties