Silicone, Polyurethane or Acrylic Latex: Which Sealant for the Joint
Most of the joints a contractor seals take one of three kinds of sealant: silicone, polyurethane or acrylic latex. They are not interchangeable. The chemistry decides what the bead sticks to, how far the joint can move, and whether you can paint over it.
Pick the family first, then the product.
Silicone: windows, glazing, glass and tile
Silicone covers several different jobs, from window and door perimeters to glazing. Perimeter caulking, glass bedding and structural glazing are separate applications, so match the product to the job specification before you compare colour or cure time.
Structural glazing bonds glass or panels as part of an assembly. Follow the project design and the manufacturer’s review requirements. Those products are not interchangeable with a perimeter caulk.
Silicone cannot be painted. If the joint will be painted, look at polyurethane or acrylic latex instead.
We carry silicone sealants from Dow, Tremco, DAP and Mulco. See the silicone sealants.
Polyurethane: construction joints that move
Dymonic 100, Vulkem 116 and TremGlaze U1500 are built for construction joints: expansion and control joints, concrete, masonry, and window and door perimeters.
Tremco rates Dymonic 100 at ±50% movement under ASTM C719. Vulkem 116 and TremGlaze U1500 are each rated ±25%.
Vulkem 116 and TremGlaze U1500 are for exterior use only. Tremco’s data sheets say not to use them inside an occupied building.
All three can be painted, but check paint compatibility first. See the polyurethane sealants.
Polyurethane sealant is not the same product as expanding polyurethane foam. The foam fills gaps around frames and is sold as its own product group.
Acrylic latex: trim, frames and anything you will paint
We carry TremFlex 834, TremGlaze SA1100, ALEX PLUS and ALEX FAST DRY. DAP lists baseboards, moulding and trim among the uses for ALEX PLUS and ALEX FAST DRY. Both contain silicone and are still acrylic latex caulks.
Paint-ready time and water-ready time are different. A surface that is ready for paint may still need more time before it can take water.
Movement is limited. TremGlaze SA1100 is rated for 12.5%, so keep acrylic latex off joints that move a lot. See the acrylic latex caulks.
The three side by side
| Type | Use it for | Watch out for |
|---|---|---|
| Silicone | Window and door perimeters, glazing, glass, tile, bathrooms | Cannot be painted; glazing and structural products are not interchangeable |
| Polyurethane | Construction joints with real movement, concrete, masonry | Check paint compatibility; some are exterior only |
| Acrylic latex | Trim, baseboard, frames, joints you will paint | Low movement; check paint-ready and water-ready times |
Deciding between two products? See polyurethane vs silicone sealant and caulking vs sealant.
Bring the product name, colour, package and quantity to the counter in Concord, Barrie or Mississauga, and we will confirm availability before you travel.