Caulking & waterproofing
Silicone caulking in San Diego
Our usual recommendation for replacing old caulking on commercial buildings, valued for its longer life expectancy.
Where we use silicone
- Replacing old caulking on commercial exteriors
- Control joint replacement
- Wet glazing and window leaks
Overview
Why we usually recommend silicone
In most cases, we suggest silicone caulking to replace old caulking on commercial buildings. Silicone generally lasts longer than urethane, though it costs more to install.
We prefer silicone over urethane, but if your project calls for urethane caulking we can supply it, and we usually price both options so you can compare.
Silicone is also used to wet-glaze windows when old gaskets no longer keep water out, and to seal leaks found during water testing.
Service at a glance
- Best for
- Replacing old caulking on commercial buildings
- Why silicone
- Generally lasts longer than urethane, though it costs more to install
- Also used for
- Wet-glazing windows and sealing leaks found during water testing
- Service family
- Concrete Caulking/Waterproofing
Where it fits
Joints where silicone is the usual choice
Silicone is chosen for exposed exterior joints that will not be painted, and for joints between glass and metal. It is the sealant we usually recommend when old caulking on a commercial exterior is replaced.
Exposed exterior joints
Wall and panel joints that face the sun and weather, where silicone’s UV stability matters.
Glass and metal
Silicone suits glass-to-metal joints, which is why it is used for wet glazing between a window and its frame.
Control joints
Replaced control joints on commercial exteriors are usually sealed with silicone, following the manufacturer’s specifications.
Silicone vs. urethane
Silicone or urethane caulking?
| Silicone | Urethane | |
|---|---|---|
| Life expectancy | Longer. | Shorter, and it breaks down faster in UV light. |
| Paintable | No. | Yes. Works well under acrylic and urethane paints and coatings. |
| Cost to install | Higher. | Lower. |
| Typical use | Replacing old caulking on commercial exteriors; wet glazing. | Joints that will be painted or covered with an elastomeric coating. |
Before choosing silicone
What silicone does well, and what to plan for
Silicone’s strengths are UV stability, temperature resistance and adhesion to many substrates. Its limits are mostly practical: it cannot be painted, and once silicone has been in a joint, only silicone will stick to it.
Strengths
- Excellent UV stability for joints in the sun
- Good adhesion to many substrates
- Good temperature resistance
- Suited to glass-to-metal joints
- Good mold resistance
Things to plan for
- It cannot be painted, so joints that will be painted or coated usually get urethane instead
- Only silicone sticks to silicone, so old silicone has to be removed completely if a different sealant will be used
- It can attract dirt, and some joints may show staining on porous surfaces
- It costs more to install than urethane
See urethane caulking for paintable joints.
Replacing old caulking
Getting a joint ready for new silicone
New silicone is only as good as its bond to the joint. What the joint needs depends on the old sealant, the condition of the joint edges, any contamination and the substrates on each side.
Removing the old sealant
Old, cracked or delaminated sealant is cut out completely rather than covered over, so the new sealant can bond well. The joint is then cleaned so no loose material, grease or dust is left to weaken adhesion.
Clean removal matters even more when sealant types change, because only silicone sticks to old silicone.
Sizing and finishing the joint
Backer rod or bond-breaking tape keeps the sealant at the size the manufacturer recommends, so it can flex as the building moves with temperature changes. The sealant is then applied and tooled so it adheres and looks clean.
Where joint edges are chipped or broken, that damage is repaired before resealing. See concrete repair and the full caulking process.
FAQ
Silicone caulking questions
Can new silicone be applied over old caulking?
It is not recommended. Old, cracked or delaminated sealant is removed completely so the new sealant can bond well, and the joint is cleaned of loose material, grease and dust. If the old caulking was silicone, remember that only silicone sticks to silicone, so any other sealant would need every trace of it removed.
Can silicone caulking be painted?
No. If a joint will be painted or covered with an elastomeric coating, urethane caulking is usually the better match, because it works well with acrylic and urethane paints and coatings.
Why do some silicone joints look dirty over time?
Silicone can attract dirt, and on some porous surfaces it can leave staining next to the joint. Choosing the right sealant for the substrate and keeping joints clean helps.
Does silicone cost more than urethane?
Yes, silicone generally costs more to install, but it usually lasts longer. We often price both options so you can compare them for your building.
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