Silicone vs. Polyurethane Sealant
ComparisonComparing the two dominant sealant chemistries for construction. Covers paintability, adhesion, flexibility, UV resistance, and best applications for each.
Quick Comparison
| Criterion | Silicone Caulk | Polyurethane Sealant |
|---|---|---|
| Paintable | No | Yes (after cure) |
| Adhesion | Best on non-porous (glass, metal, tile) | Best on porous (wood, concrete, masonry) |
| UV Resistance | Excellent | Good (paint or UV-stable formulas recommended) |
| Flexibility | Superior long-term | Very good |
| Cleanup | Mineral spirits | Mineral spirits (uncured); scrape (cured) |
Our Recommendation
Use silicone for wet areas, metal-to-glass, and anywhere paint is not needed. Use polyurethane for exterior trim joints, concrete, and any location that will be painted.
Detailed Analysis
Both sealant types last 20+ years when properly applied. The choice comes down to paintability (polyurethane wins) vs. flexibility and non-porous adhesion (silicone wins).