Singapore's window and glass panel waterproofing specialist.

Windows and glass panels are the most exposed waterproofing detail in any Singapore building. They sit at the intersection of three substrates — aluminium frame, structural opening and glazing — and every joint between them is asked to hold back tropical rain, UV, thermal movement and decades of cyclical loading. When any one of those joints fails, water finds its way in. The right fix is rarely a cosmetic re-paint of the reveal. It is a properly diagnosed sealant replacement, executed to manufacturer specification, with the warranty written down.

The most common call we get: a window leak repair that someone else already tried. A handyman applied a bead of silicone, the leak stopped for two storms, then came back somewhere else along the head. Window leak repair done properly means stripping the failed joint, preparing the substrate, sizing the backing rod and applying a manufacturer-certified sealant with the correct primer — not a cosmetic wipe over the old bead.

Why windows leak in Singapore — and why a wipe of new silicone won't hold.

Singapore is one of the most aggressive environments in the world for window and curtain-wall sealants. Daily UV intensity is high, ambient humidity rarely drops below 65 per cent and wind-driven rain regularly exceeds 30 metres per second at upper-floor elevations. A perimeter sealant designed for a temperate climate, or specified to the wrong manufacturer grade, often begins to chalk, shrink and split within five to seven years. That is fast enough that most landed homes, condominiums and MCST developments are now on their second or third sealant generation — and many have never had a proper specialist sealant survey in between.

The most common call we get is an aluminium window leak that someone else already tried to fix with a bead of general-purpose silicone. The classic Singapore window leak follows a predictable pattern. The first sign is usually a hairline dark stain along the inside of the window reveal, most visible after a north-east monsoon downpour. The owner repaints the reveal. The stain returns. A handyman is called, who applies a bead of general-purpose silicone over the outside perimeter. For one or two storms the leak is masked. Then water finds the next weakest point and the stain migrates a few centimetres along the head. The cycle repeats until the timber sub-frame is rotten, the plaster is delaminating or the parquet below the sliding door has lifted.

The reason a wipe of silicone rarely holds is that the joint it covers is not a smooth surface. It is a complex three-dimensional gap between an aluminium frame, a concrete or brick opening, and — in newer buildings — a curtain-wall transom or mullion. Without proper joint preparation, backing rod sizing and sealant selection, the new bead bonds to dust, old sealant residue or paint flakes. It looks tidy on day one and fails on the first wet-and-dry cycle.

Six failure types we diagnose.

Not every "window leak" has the same cause. Treating them all the same way is the single most common reason rectification work fails to hold. Our survey starts with a structured failure classification:

1. Perimeter sealant failure. The most common defect. The joint between the aluminium frame and the structural opening has chalked, split or pulled away from one substrate. Driven by UV degradation, wrong primer, undersized backing rod or simple end-of-life.
2. Internal frame joint failure. Mitred or butt joints inside the aluminium frame itself have opened up. Water entering at the head tracks horizontally through the frame, exits at the jamb and stains the wall below — making diagnosis confusing because the water exit is not above the entry point.
3. Sliding-door track and threshold leakage. Track screws, weep holes and stop-end caps allow water to bypass the drainage path. The threshold sealant is often masked under timber flooring and only discovered when the parquet starts to lift.
4. Structural silicone failure on curtain walls. On structurally-glazed curtain walls, the silicone is doing more than waterproofing — it is also bonding the glass to the frame. Failure here is both a leakage and a safety concern, and is treated under a separate specialist scope.
5. Glazing gasket and EPDM failure. The wet-glaze gasket between the glass edge and the frame has hardened, lost compression set or migrated. Common in older aluminium windows on landed homes.
6. Capillary leakage at louvres and openable vents. Aluminium top-hung and casement vents allow capillary action to draw water along closed-position gaskets. Often misdiagnosed as a sealant problem when it is in fact an ironmongery problem.

We classify the leakage type, document it with photographs and a written diagnosis, and then specify the correct system. A window head failure and a track threshold failure are different jobs with different products. We have seen contractors quote the same scope for both — and the second leak always comes back.

Sealant systems we install.

There is no single "best" sealant for window waterproofing. The right system depends on substrate, joint width, anticipated movement and warranty period. We work with manufacturer-certified products only, and our installers apply them strictly to the technical data sheet — primer, joint preparation, backing rod sizing, tooling and cure conditions.

• Low-modulus neutral-cure silicone — the default specification for perimeter joints between aluminium frames and concrete or brick openings. High UV resistance, large movement accommodation, suitable for Singapore's thermal cycling. Standard expected life: 15–20 years when correctly installed.
• Medium-modulus structural silicone — used on structurally-glazed curtain walls where the silicone is also part of the load path. Specification, joint dimensioning and adhesion testing are mandatory; this is not a handyman scope.
• Polyurethane sealants — high-movement, paintable, used on certain timber and metal-to-concrete joints where the joint may need over-coating. Lower UV resistance than silicone, so generally limited to protected joints.
• MS polymer (modified silane) sealants — hybrid chemistry, paintable, low odour, good adhesion without primer on many substrates. Used in interior detailing and sensitive applications.
• Pre-formed EPDM gaskets and tapes — used as a secondary barrier behind the primary sealant in curtain-wall and high-exposure detailing. The principle is two lines of defence with a drainage cavity between them.

Sealant alone is not a system. A correct window waterproofing detail uses backing rod sized to give the right joint depth, a primer where the substrate requires one, and a tooled bead that creates the correct hour-glass cross-section. Skip any of those and the sealant fails on a fraction of its rated life — even if the chemistry on the cartridge is the right one.

A full perimeter sealant replacement — what's actually involved.

For a typical landed-home or condominium window perimeter replacement, our specification reads as follows:

1. Survey and joint mapping. Every window opening is logged, joint widths are measured, failure modes are photographed. The output is a joint schedule that drives material quantities and the warranty register.
2. Internal protection. Furniture sheeted. Floor tracked. Where work is interior-side, additional dust containment with negative-pressure extraction.
3. Sealant removal. Existing failed sealant cut out cleanly with appropriate blades. We do not cap over old sealant — a sealant joint built on residue inherits the failure.
4. Substrate preparation. Joint faces cleaned, dust removed, contaminants wiped with the manufacturer-specified solvent. Friable substrate stabilised.
5. Backing rod installation. Closed-cell polyethylene backing rod sized to deliver a 1:2 depth-to-width ratio (with a minimum and maximum joint depth per the data sheet). The backing rod gives the bead its correct cross-section and prevents three-sided adhesion.
6. Primer application. Where the data sheet calls for a primer on aluminium, glass or porous substrate, primer is applied and given the specified flash-off time before sealant is gunned.
7. Masking. Painter's tape masked along both edges of every joint. Edges crisp; no smearing.
8. Sealant application and tooling. Cartridge or sausage applied in a continuous bead, then tooled with the correct spatula in a single pass. Tooling pressure compresses the sealant into the joint faces — this is the bond-development step.
9. De-masking. Tape removed while the sealant is still wet to leave a clean line.
10. Cure and adhesion check. The sealant is left to skin and cure. After full cure, sample joints are pull-tested. Any failure is rectified before sign-off.
11. Water test. A controlled spray test is run on representative joints — typically a hose simulating wind-driven rain. We do not hand over until tested joints stay dry on the interior face.
12. Handover. Photo log of every elevation, joint schedule, warranty certificate.

That sequence is the same whether we are sealing six windows on a landed home or 4,000 metres of perimeter joint on a condominium repaint. The discipline is identical; only the rope-access logistics and crew size change.

Rope access and high-rise glass panels.

Most window and curtain-wall waterproofing on Singapore high-rises is delivered from rope access rather than scaffold. Our IRATA-trained technicians are qualified to abseil from approved anchor points and work on joints at any elevation that scaffold cannot economically reach. Rope access changes the commercial picture entirely: a job that would have required a six-week scaffold programme, MCST approval for compound space and a five-figure scaffold fee can typically be completed in two to three weeks with no scaffold at all.

The technical work on rope is identical to ground-level work. Sealant removal, joint preparation, backing rod, primer, application and tooling all happen one joint at a time. The difference is operational — anchor planning, exclusion zones at ground level, weather windows and MOM-compliant work-at-height permits. We take that operational load off the MCST or building owner. The client sees a clean joint, a written warranty and a single point of contact.

Curtain-wall and structural-glazing work has additional governance. Where the silicone forms part of the structural bond, we engage the original system manufacturer or an equivalent specialist consultant for adhesion testing and specification sign-off. We do not improvise on structural silicone. The cost of a wrong call there is not a leak; it is a glass panel out of plane.

Warranty & what's covered.

Every Shieldguard window and glass-panel waterproofing job is delivered with a signed workmanship warranty certificate. Standard cover:

• Up to 10 years on full perimeter sealant replacement using high-grade neutral-cure silicone, correctly primed and tooled.
• Up to 7 years on partial elevation re-seals where adjoining joints remain in serviceable condition.
• Up to 5 years on threshold and sliding-door track re-sealing where ironmongery is sound and weep paths are clear.
• Up to 5 years on glazing gasket replacement in aluminium-framed residential windows.

The warranty is on Shieldguard letterhead, with a register of every joint location and the system applied. When something needs attention, the client calls one number and we attend. No manufacturer helpline, no buck-passing.

Window & glass panel waterproofing FAQs.

Related pages: External wall waterproofing · Rope-access painting · Building repair