Sealant around windows and façade joints is a small part of a building’s budget, but when it fails it causes a large share of water ingress complaints. Sydney’s UV, heat and coastal salt age sealant faster than many owners expect, and most of it sits where nobody looks closely: several storeys up on the outside of the building.
Here’s what failing sealant looks like and what to do about it.
Six signs the sealant has reached the end of its life
- Cracking or crazing. Fine surface cracks, or deeper splits across the bead.
- Hardening. Good sealant stays flexible. If it feels hard or brittle, it can no longer move with the building.
- Adhesion failure. The bead has pulled away from the frame or the wall on one side, leaving a gap.
- Shrinkage. The bead has thinned or sunk below the edges of the joint.
- Missing sections. Gaps where the sealant has fallen out or was never continuous.
- Staining, mould or water marks below windows or joints, inside or outside.
If residents are already reporting leaks around frames, the sealant is a likely suspect, but not the only one. Flashings, cracks and sill details can also be involved, which is why a proper leak investigation comes before a large resealing scope. We explain how that works in why buildings leak in wind-driven rain.
Why you can’t just run a new bead over the old one
Applying fresh sealant over failed sealant is a common shortcut, and it rarely lasts. New sealant needs a clean, sound surface to bond to. Laid over old material, it bonds to something that is already failing and will pull away with it.
A proper replacement involves:
- Cutting out and removing the old sealant completely.
- Cleaning and preparing the joint surfaces.
- Installing backing rod where the joint depth needs it.
- Priming where the substrate and product require it.
- Applying a commercial-grade sealant suited to the joint and substrate, then tooling it to the right profile.
How rope access makes resealing practical
On a multi-storey building, resealing every window from scaffolding is expensive and disruptive for residents. On rope access, technicians work drop by drop down the façade, can reach individual windows and joints directly, and can often combine resealing with other work on the same setup, such as crack repairs, façade painting or cleaning.
When to plan it
- Before repainting. Replacing failed sealant before a repaint protects the new paint and avoids repainting over a defect.
- After repeated leak reports on the same elevation or stack of units.
- As part of a maintenance plan. Sealant has a service life. Building it into the capital works or maintenance plan avoids emergency call-outs later.
Get your building’s sealant checked
Ace Abseiling replaces window and joint sealant on strata and commercial buildings across Sydney using rope access. See our caulking and sealing service or request an inspection.
