Sealant is easy to overlook until a resident reports a leak. The joints around windows, between precast panels and at expansion joints are what keep wind-driven rain out of the building, and in South Florida's sun, heat and salt air they wear out faster than most people expect.
This guide explains how long common sealants last, how to tell when yours is failing, and how to plan replacement so it doesn't turn into an emergency.
How long does sealant last?
It depends mostly on the type of sealant, the quality of the original installation and how much sun the joint gets.
- Silicone sealants are the most durable for exposed joints. Manufacturers and building envelope consultants commonly cite a service life of 20 years or more for good-quality silicone that was installed correctly.
- Polyurethane sealants bond well to concrete and masonry and can be painted, but they break down faster under UV. In strong sun, exposed polyurethane joints often need attention within about 5 to 10 years.
- Any sealant fails early if the joint wasn't cleaned and primed properly, if it's the wrong width or depth, or if it was applied over old sealant.
Signs your sealant is failing
- Cracks, splits or gaps in the sealant bead.
- Sealant pulling away from one or both sides of the joint (adhesive failure).
- Hard, shrunken or chalky sealant that no longer gives when pressed.
- Missing sections of sealant or exposed backer rod.
- Water stains, bubbling paint or damp drywall inside units near windows. See Window Leak Repair.
How often to inspect
A common rule of thumb from sealant guidance is to inspect joints at intervals of about one fifth of their expected life, and to check movement joints closely after the first year. For most buildings that means a close look every few years, plus a check after any major storm.
Window cleaning visits are a good time to spot problems, because the crew is already on the facade. Ask your contractor to photograph and note any joints that look cracked or debonded.
Spot repair or full replacement?
If only a few joints have failed and the rest are in good shape, targeted repairs make sense. If failures are showing up across an elevation, or the sealant is near the end of its expected life, a full replacement is usually more cost-effective than repeated callbacks.
Either way, the old sealant should be cut out completely. Caulking over failed sealant doesn't bond and fails quickly. The joint should be cleaned, primed where the manufacturer requires it, fitted with backer rod and then sealed. See Commercial Caulking & Joint Sealing.
Planning and budgeting
- Track when each elevation was last sealed and with what product.
- Include sealant replacement in your reserve planning. Florida's structural integrity reserve study requirements cover waterproofing and windows for many condominium buildings. See our guide to Florida Milestone Inspections: What They Mean for Your Building's Exterior.
- Combine sealant work with painting or waterproofing to share access costs. See Commercial Waterproofing and Commercial Exterior Painting.
- Schedule the work in the drier months, roughly November through April, when rain delays are less likely.