You might know this as joint sealant. Same work, either name. We replace failed exterior joint sealant on commercial buildings — precast and panel joints, window perimeters and expansion joints. This is the work that keeps water out of the wall before it reaches anything expensive inside.
Elevations walked or dropped, joint types and widths recorded, and adhesion pull tests done on the existing sealant. This determines which joints are failing and what the replacement product has to bond to.
Existing sealant cut out to the substrate on both faces and the joint cleaned. Residue left behind is the most common cause of a new sealant failing early.
Closed-cell or open-cell rod installed to set joint depth and prevent the sealant bonding to the back of the joint. Bond breaker tape used where the joint is too shallow for rod.
Substrate primed where the manufacturer requires it, then sealant gunned and tooled in one pass to full contact on both faces at the specified width-to-depth ratio.
A test section installed and pull-tested before the full run, then spot tests during the work. This is standard on specified projects and worth requesting on any large elevation.
Spray testing suspect areas to confirm the leak path before and after work. Necessary when the complaint is an interior leak rather than visibly failed joints.
If you are seeing any of this, call us before it gets more expensive.
| What you are seeing | What it usually means |
|---|---|
| Sealant pulled cleanly off one joint face | Adhesion failure; usually bad prep or missing primer |
| Sealant split down the middle of the joint | Cohesive failure; product movement capability was too low |
| Dark staining running below joints on stone | Plasticizer migration from the wrong silicone formulation |
| Interior stains at window heads after wind-driven rain | Perimeter seal breached above; water is traveling before showing |
Joints inspected and measured, substrates identified, and adhesion tested. Product is selected for movement capability and substrate compatibility, not for what is on the truck.
A sample run installed, cured, and hand pull-tested to confirm adhesion and primer requirements. Color is approved against the wall in daylight since cured color differs from the tube.
Lift, stage, or rope access rigged, and sidewalks, glass, and landscaping protected. Tenants near the work get notice, particularly where windows must stay closed.
Old sealant removed to sound substrate on both faces, joints cleaned by grinding or a two-cloth solvent wipe, and dust blown out. Joints are sealed the same day they are prepped.
Backer rod set to depth, primer applied where required, sealant gunned and tooled to full contact on both joint faces. Tooling is what forces the hourglass profile that lets the joint move.
Sealant cures for the product's stated period, then spot adhesion checks and any water testing. Close-out should include product data sheets, warranty documents, and a marked-up elevation of what was replaced.