A tenant on the eleventh floor of a St Kilda Road office building reports a brown tide mark creeping across a ceiling tile beside the window line after three days of southerly rain. The in-house maintenance contractor runs a bead of silicone around the inside of the window frame, the stain stops growing for a fortnight, and then the next front comes through and the tile collapses onto a workstation. The internal seal did nothing because the water was never entering from inside. It was tracking through a perimeter sealant joint on the external face of the building that had split, debonded and hardened after two decades of western sun, and it was running down inside the frame until it found the first weak point. That scenario plays out across Melbourne’s commercial building stock every winter, and it is almost always a problem that correct, planned facade resealing would have prevented.

Sealant is the least expensive component of a building envelope and one of the most consequential. It is also the component most likely to fail first, because it is expected to stretch, compress, resist UV and stay bonded to glass, aluminium, concrete and stone for years at a time without attention. For facilities managers, property managers and owners corporations, the challenge is rarely deciding whether sealant needs attention. The challenge is getting a qualified technician to the joint safely, doing the work to a standard that actually lasts, and documenting it in a way that stands up to warranty, insurance and compliance scrutiny.

This guide explains how facade resealing works on commercial and strata buildings, why rope access has become the preferred method for most Melbourne elevations, what the Victorian regulatory framework requires of you as a duty holder, and how to scope and procure the work so the result lasts well beyond the next wet season. It is written for the people who approve the scope, manage the contractor and field the call from tenants when a ceiling tile starts to stain.

What Facade Resealing Actually Involves

The term covers more than most building owners expect. Facade resealing is the removal of aged or failed sealant from the external joints of a building and its replacement with a new, correctly specified sealant system. On a typical commercial building, that includes window and door perimeter joints where the frame meets the structural opening, curtain wall stack and mullion joints, expansion and control joints in precast concrete or masonry, junctions between cladding panels, flashing and coping laps at parapets, and penetrations where services pass through the external wall.

Each joint type moves differently and fails differently, so the work is not a single product applied uniformly across the elevation. A perimeter joint on an aluminium window frame might see thermal movement of a few millimetres across a day in January. An expansion joint between precast panels on a twenty-storey tower is designed to absorb much larger structural and thermal movement, and it needs a sealant with a correspondingly higher movement capability. Getting the specification wrong at this level is one of the most common reasons a resealed facade starts leaking again within a few years.

Weatherseals Versus Structural Glazing

A critical distinction for any facilities manager is the difference between weatherseal joints and structural silicone glazing. Weatherseals keep water and air out. Structural silicone, used in some curtain wall and four-sided glazing systems, actually holds the glass to the frame and carries wind load. Structural joints are engineered components, and any work on them must follow the glazing system manufacturer’s requirements and, in most cases, involve an engineer and a specialist glazier. Routine facade resealing deals with weatherseals. A competent contractor will identify structural joints during the pre-work inspection and refuse to treat them as ordinary maintenance.

Why “Cap Sealing” Over Old Sealant Fails

One shortcut that appears regularly on Melbourne buildings is overcoating or capping failed sealant with a fresh bead rather than cutting it out. It looks acceptable from the ground and costs less on the day. It almost never works. New sealant bonds poorly to old, chalked or contaminated sealant, the joint geometry is wrong, and the original failure point remains in place underneath. Genuine facade resealing requires full removal of the existing material back to clean substrate, and any quote that does not state this explicitly should be questioned.

Why Sealants Fail on Melbourne Buildings

Melbourne is a harsh environment for building sealants, and it is harsh in several different ways depending on where the building sits. A glass tower in Docklands, an office building fronting Collins Street and a strata block in Brighton will each wear out their joints in different ways and at different rates.

Thermal Cycling and UV Exposure

Melbourne’s well-known ability to move between cool mornings and hot afternoons within a single day creates continuous thermal cycling across a facade. Aluminium framing expands and contracts significantly with temperature, and dark-coloured panels and frames on north and west elevations reach surface temperatures far above the ambient air. Every cycle stretches and compresses the sealant. Combined with high UV exposure over an Australian summer, this gradually hardens most sealants, reduces their elasticity, and eventually causes them to split or pull away from the substrate. The same building will often show markedly different sealant condition on its western face compared with its southern face, which is why elevation-by-elevation assessment matters.

Coastal Salt Air

Buildings in Port Melbourne, St Kilda, Elwood, Brighton, Sandringham, Williamstown and along the Mornington Peninsula face an additional challenge. Salt-laden air deposits chlorides on frames and joint surfaces, accelerates corrosion of aluminium and steel substrates, and compromises adhesion at the bond line. Once the substrate begins to corrode beneath the sealant, the joint fails even if the sealant itself is still flexible. Our guide to window cleaning for coastal areas of Melbourne covers how salt deposition affects glass and frames, and the same exposure conditions should shorten your facade resealing inspection interval on bayside properties.

Wind-Driven Rain on Exposed Towers

High-rise buildings in the CBD, Southbank and Docklands experience wind-driven rain that pushes water horizontally and even upward into joints that would stay dry on a low-rise building. Positive wind pressure on the windward face forces water into any gap, and a hairline separation at a sealant bond line that would be harmless at ground level becomes a significant leak at level twenty. Pressure differentials also explain why leaks often appear on one floor while the defect is several metres away, because water tracks through cavities, frame sections and slab edges before it becomes visible inside.

Building Movement and Poor Original Detailing

Newer buildings settle, shrink and creep in their first years, and some joints on recently completed buildings fail because the original design did not allow for the movement that actually occurred. Other failures trace back to construction: joints installed too shallow or too deep, missing backing rod, three-sided adhesion where the sealant has bonded to the back of the joint and cannot stretch, or sealant applied to damp or dusty surfaces during a rushed handover. When facade resealing is carried out on a building less than ten years old, it is worth establishing whether the defect is a maintenance issue or a latent construction defect, because the answer affects who pays.

Recognising Sealant Failure Before It Becomes a Leak

The most cost-effective facade resealing programmes are driven by condition, not by leaks. Facilities managers who wait for water to appear inside are paying for the reseal plus internal make-good, tenant disruption and, in some cases, mould remediation and insurance excess.

Sealant failure has recognisable stages. Chalking and surface crazing indicate UV degradation and hardening. Adhesive failure appears as the sealant peeling cleanly away from one side of the joint, leaving a gap. Cohesive failure shows as a split running down the centre of the bead, meaning the sealant itself has torn. Substrate failure, where the sealant pulls away a layer of paint, render or corroded metal with it, tells you the problem sits in the surface beneath rather than the product. Missing sections, bird damage, and sealant that has been painted over and cracked through the coating are also common findings.

Internal signs include staining at window heads and sills, swelling or delaminating plasterboard linings near the facade, efflorescence on internal masonry, corrosion of window hardware, and persistent condensation or dampness at the perimeter of floor plates. Occupants will often report draughts or whistling around windows before any water appears, because air leakage and water leakage share the same pathways.

The best early warning system is close-range observation, and this is where routine maintenance access delivers real value. This complements our detailed breakdown of building facade inspections during window cleaning, which explains how technicians working on the face of the building every quarter can log sealant condition elevation by elevation and flag deterioration long before it produces a leak.

Why Rope Access Suits Facade Resealing

Sealant work is slow, detailed and hands-on. A technician needs to cut out old material, clean and prime the substrate, install backing rod, apply the sealant and tool it, often across hundreds of linear metres of joint spread over every floor of a building. The access method has to put the technician in a stable position directly at the joint for extended periods, move efficiently across the elevation, and do so without closing streets or disrupting tenants for weeks.

Comparing Access Methods

Scaffolding provides an excellent working platform but is expensive to erect on a multi-storey building, often requires council permits and footpath occupation, restricts natural light to tenancies, and creates security concerns for the duration of the project. For a full facade recladding it can make sense. For facade resealing, where the work itself might take a small crew a few weeks, the scaffold cost can exceed the cost of the sealing.

Elevating work platforms suit low-rise buildings with good ground access, and an EWP with a boom length of 11 metres or more requires an operator holding the relevant high-risk work licence. On buildings above four or five storeys, on sloping sites, or where landscaping, awnings or basement slabs restrict machine placement, EWPs quickly become impractical.

Building maintenance units are designed for facade access and can be well suited to sealant work where the building has one, although BMU availability, certification status and the unit’s reach across setbacks and returns all determine whether it can cover every joint. Swing stages offer similar capability on buildings with suitable davits or parapet clamps, but they require rigging time and move slowly across complex facades.

Rope access, by contrast, can be rigged from certified roof anchors in hours, reaches setbacks, returns, soffits and awning-obstructed areas that platforms cannot, and moves laterally between drops quickly. The access equipment occupies a footprint no larger than a ground exclusion zone, and tenants often barely notice the work is underway. For most Melbourne commercial and strata buildings, rope access is the most efficient way to deliver facade resealing to a high standard. The photograph accompanying this article, showing a technician resealing a vertical glazing joint on a tiled and louvred facade, illustrates exactly the kind of elevation where louvres, sunscreens and a varied facade profile would make platform access slow and awkward.

How IRATA Rope Access Is Configured

Under the IRATA International system, every technician works on two independently anchored ropes: a working line fitted with a self-braking descender, and a separate safety line fitted with a back-up device that will arrest a fall if the working line or descender fails. Teams are structured by certification level, with a Level 3 technician supervising the work, managing the rescue plan and taking responsibility for rigging and anchor selection. Every anchor used must be certified and within its inspection period, and every rope, harness and device is subject to documented inspection before and during use. For a detailed explanation of how these systems operate on the face of a building, see our overview of how we safely perform abseiling and rope access window cleaning.

Sealant work adds considerations of its own. Sealant guns, knives, primers, masking tape and cleaning solvents all have to be carried on the rope, and every item must be tethered to the technician or held in a closed bag to prevent dropped objects. Solvent use at height has to be planned for ventilation and ignition sources near building intakes. Technicians also need a stable work position for accurate tooling, which is achieved through positioning lanyards, suction-based stabilisers on glazing, or rope configurations that hold the technician against the facade rather than swinging away from it.

The Facade Resealing Process, Step by Step

A properly executed facade resealing project follows a consistent sequence, and facilities managers should expect a contractor’s method statement to reflect each stage. Skipping any one of them is the usual explanation when a newly sealed joint fails within its first few years.

1. Condition Survey and Joint Schedule

Work should begin with a close-range survey that records joint types, dimensions, existing sealant type where it can be identified, failure modes and substrates on each elevation. The output is a joint schedule and photographic record that allows the specification to be set joint by joint rather than guessed. On buildings with known leaks, water testing in general accordance with AS 4284 methodology, or controlled spray testing of suspect areas, can confirm the ingress point before money is spent sealing joints that were never the cause.

2. Specification and Compatibility Testing

Sealant selection depends on joint movement, substrate, exposure and compatibility with adjacent materials. Neutral-cure silicones are widely used on glazing and aluminium perimeters because of their UV resistance and movement capability. Polyurethanes and modified silicone polymers are common on concrete and masonry joints and can be overpainted where colour matching matters. Some natural stone substrates require non-staining formulations to prevent oil migration and permanent marking. Manufacturers generally recommend field adhesion testing on the actual substrate before full-scale work begins, and many will only warrant the system when adhesion tests have been documented.

3. Removal of Existing Sealant

Old sealant is cut out completely using knives and oscillating tools, taking care not to damage anodised or powder-coated finishes, glass edges or gaskets. Residual sealant film is mechanically removed, because new sealant will not bond reliably to cured silicone residue. On buildings where original sealant may contain hazardous materials, including some older polysulfide sealants, testing and a specific control plan may be needed before removal begins.

4. Substrate Preparation

Surfaces are cleaned, typically using a two-cloth solvent method on non-porous substrates, and primed where the manufacturer’s data requires it. Substrates must be dry, sound and free of dust, oil, salt and release agents. This is where interaction with glass treatments matters: hydrophobic coatings applied to glass to repel water and reduce cleaning frequency also repel sealant, so any coating on the bond surface must be removed before sealing. Coordinating facade resealing with your window cleaning programme is sensible for exactly this reason, as a pure water clean of the glass and frames before sealing work removes surface contamination without leaving detergent residue, and TDS readings on the rinse water confirm the water is not depositing minerals on the bond surfaces.

5. Backing Rod, Bond Breaker and Joint Geometry

A closed-cell backing rod is installed to control sealant depth and create the correct hourglass profile, with a bond breaker used where the joint is too shallow for rod. The rod prevents three-sided adhesion, allowing the sealant to stretch between the two sides of the joint rather than tearing as it tries to move while bonded to the back. Joint width-to-depth ratios follow the sealant manufacturer’s guidance, and joints that are too narrow for the movement they experience may need to be widened or redesigned rather than simply refilled.

6. Application and Tooling

Sealant is applied in a continuous bead that fills the joint fully, then tooled to press it into contact with both sides and create a smooth, concave finish that sheds water. Masking tape is used for clean lines and removed before the sealant skins. Application is controlled by weather: most sealants have minimum and maximum substrate temperatures, and work should not proceed on wet surfaces, in rain, or when rain is forecast before the sealant has skinned. Melbourne’s variable weather means well-run facade resealing projects carry realistic weather allowances in the programme rather than pushing work through marginal conditions.

7. Quality Records and Handover

Each completed drop should be photographed and recorded against the joint schedule, with product batch numbers, primer use, adhesion test results and weather conditions logged. This record supports manufacturer warranties, gives your maintenance plan a baseline for future inspections, and provides evidence if a leak dispute arises. A contractor unwilling to provide this documentation is effectively asking you to take the quality of hidden work on trust.

Windows, Glazing and Seal Integrity

Window perimeters are where most facade leaks originate, and window glazing deserves specific attention within any facade resealing scope. A window perimeter concentrates several materials, several sealing layers and a drainage system into a small area, and a failure in any one of them can present inside the building as the same stain on the same ceiling tile.

Glazing systems rely on several sealing layers working together. The perimeter sealant keeps water out of the junction between the frame and the building. Glazing gaskets, usually EPDM, seal the glass into the frame, and they shrink with age, pulling back at corners and leaving gaps that admit water directly into the frame. Wet-sealed glazing uses a sealant bead in place of a gasket at the glass-to-frame interface. Within insulated glass units, the edge seal keeps moisture out of the cavity between panes, and when it fails the unit fogs internally, a condition that cannot be cleaned and signals that the unit needs replacing.

Frames themselves are designed to manage some water. Most commercial window and curtain wall systems include drainage paths and weep holes that let water that gets past the outer seal drain back to the exterior. One of the most damaging errors in poorly executed sealing work is sealing over weep holes and drainage slots, which traps water inside the frame and sends it into the building instead. Your contractor should understand the drainage design of the system being sealed and keep it open. Performance expectations for windows and external glazed doors are set out in AS 2047, and glass selection and replacement must comply with AS 1288, so any glazing replacement undertaken alongside the sealing work must meet these requirements.

Rope access allows gasket replacement, wet reglazing of smaller panels, and replacement of individual insulated glass units within handling limits to be completed in the same mobilisation as the facade resealing. Larger panels will usually need a BMU, crane or glazing robot, and the survey stage should identify these early so the access plan accounts for them. When sealant, gaskets and glass units are assessed together, the building manager gets a single picture of envelope condition rather than a series of disconnected repairs.

Your Obligations as a Duty Holder in Victoria

Facade resealing is construction work under Victorian law, and the access method means it is also work at height. That places obligations on the building owner and anyone with management or control of the workplace, not only on the contractor.

The OHS Act and Regulations

Under the Occupational Health and Safety Act 2004, persons with management or control of a workplace must ensure, so far as is reasonably practicable, that the workplace and the means of entering and leaving it are safe. Part 3.3 of the Occupational Health and Safety Regulations 2017 deals with the prevention of falls and requires fall risks to be controlled using the hierarchy of control. Where a fall of more than two metres is possible, the work is high risk construction work, and a Safe Work Method Statement must be prepared before it starts. The SWMS should address the specific access method, rescue arrangements, dropped object controls, solvent handling and public protection, and it must be reviewed if conditions change.

As a building manager, you should receive and review the contractor’s SWMS, confirm that roof anchors used for rope access are certified and in date, verify that the contractor’s insurances and technician certifications are current, and ensure information about building-specific hazards is shared, including roof plant, fragile roofing, energised equipment near parapets and areas where exhaust discharge could affect technicians. As covered in our guide to height safety compliance for Melbourne commercial buildings, the anchors and static lines on your roof are part of your own compliance obligations, and anchors must be inspected at intervals consistent with AS/NZS 1891.4 and the manufacturer’s requirements. Anchors that have lapsed certification cannot be used for sealant work or any other rope access work until they are re-inspected.

Public Protection and Permits

Dropped objects are one of the key risks on any facade project. Exclusion zones must be established beneath every drop, and where the work zone extends over a public footpath or roadway, permits from the relevant council will usually be required. In the CBD, the City of Melbourne’s requirements for footpath occupation, hoarding and traffic management can add lead time to a project, and CBD buildings with narrow frontages onto laneways often need gantries or timed closures. Facilities managers planning facade resealing on a city building should factor permit lead times into the programme, and our guide to CBD high-density window cleaning logistics sets out the pedestrian management and permit considerations that apply equally to sealant work.

Essential Safety Measures and Fire-Rated Joints

Most external weatherseal joints are not essential safety measures under the Building Regulations 2018. Some joints near the facade, however, are part of the building’s passive fire protection, including fire-rated sealants at slab edges, compartment boundaries and service penetrations. These must only be replaced with systems tested and approved for the required fire resistance level, and changes should be recorded as part of your ESM maintenance records. A contractor who treats a fire-rated joint as an ordinary weatherseal creates a compliance problem that may not surface until your next annual essential safety measures report. Where building permit questions arise, including changes to glazing configuration or fire-rated elements, the Building and Plumbing Commission Victoria, which replaced the Victorian Building Authority on 1 July 2025, is the relevant regulator.

Strata, Owners Corporations and Planning the Budget

For residential and mixed-use buildings, external sealant joints almost always form part of common property, which places responsibility for their maintenance with the owners corporation rather than individual lot owners. Where an owners corporation is required to maintain a maintenance plan under the Owners Corporations Act 2006, facade resealing should appear as a scheduled item with an estimated interval and cost, not as a reactive line that only surfaces when a resident reports a leak. Our explainer on owners corporation law and window cleaning responsibilities covers how common property obligations are divided, and the same principles apply to the building envelope.

Sealant lifespan varies widely with product, exposure and installation quality, and manufacturers’ own guidance is the best basis for planning. What is consistent is that joints on the hottest and most exposed elevations fail first. Many buildings benefit from staged facade resealing, treating the western and northern elevations before the sheltered faces, which spreads capital expenditure across financial years while addressing the highest-risk joints first.

Cost drivers for a sealant replacement project in Melbourne include the total linear metres of joint, joint width and depth, the number of separate drops required to cover the building, the complexity of removing existing material, the sealant system specified, the need for adhesion testing and water testing, permit and traffic management costs, and weather allowances. Quotes presented as a simple rate per linear metre in Australian dollars can be useful for comparison, but only if every contractor is pricing the same scope, including full removal, backing rod, priming and documentation. The cheapest price is often the one that quietly assumes capping over old sealant.

Coordinating Resealing With Other Facade Work

One of the most practical ways to control the cost of facade resealing is to combine it with other work that already puts technicians on the face of the building. Every rope access mobilisation carries fixed costs: site setup, anchor verification, exclusion zones, permits and rescue arrangements. Sharing those costs across several scopes of work reduces the cost of each.

The most natural pairing is commercial window cleaning. A sealing programme can be sequenced with a scheduled clean, with the glass and frames cleaned first to prepare bond surfaces, followed by sealing on the same drops. Technicians cleaning the building quarterly also provide ongoing condition monitoring of the new joints. Buildings with a high-rise window cleaning programme already have rope access or BMU arrangements in place, which shortens the planning cycle for sealant work considerably.

Other scopes that combine well with facade resealing include render and concrete repairs, cladding panel refixing, gutter and box gutter clearing, bird proofing, signage removal, and repainting of frames and facade elements. McPherson’s commercial facade repairs capability allows sealant replacement, crack repair and panel rectification to be delivered by the same IRATA-certified team in a single programme, which also simplifies accountability if a defect reappears.

Where water ingress has already occurred and the source is uncertain, diagnosis should precede sealing. Our commercial leak detection and repair service uses rope access close inspection, controlled water testing and moisture mapping to confirm the entry point, so resealing budgets are spent on the joints that are actually failing. After a severe weather event, a fast inspection can also distinguish between genuine sealant failure and storm-related damage, which matters for insurance claims, as discussed in our post on window cleaning after storms.

Choosing a Facade Resealing Contractor

The quality of sealant work is largely invisible once it is complete, which makes contractor selection more important than it is for most maintenance scopes. A joint that has been cut out, primed, backed and tooled correctly looks almost identical from the street to one that was capped over dust.

Facilities managers assessing contractors for facade resealing should look for current IRATA certification for every technician on the rope, with a Level 3 supervisor on site, alongside verifiable experience in sealant application rather than rope access alone. Ask for a sample method statement and SWMS, a sample joint schedule and photographic handover record from a previous project, and confirmation that the contractor will follow the sealant manufacturer’s installation requirements and complete adhesion testing where the manufacturer requires it. Check insurances, safety performance measures such as LTIFR, and the contractor’s approach to dropped object prevention and rescue planning. Ask how the contractor identifies structural glazing joints and fire-rated joints, and what they do when they find them.

It is also worth asking what happens after the work is finished. Contractors who also provide height safety services and routine building maintenance can maintain the anchors your future work depends on, monitor sealant condition during scheduled cleans, and address isolated defects before they spread. That continuity is often worth more than a marginal difference in the initial quote.

Planning Your Facade Resealing Programme

The buildings that avoid chronic leaks are not the ones with the most expensive sealant. They are the ones where someone has a clear picture of joint condition, a schedule for treating the most exposed elevations before they fail, and a contractor who does the unglamorous preparation work properly. Facade resealing managed this way becomes a predictable line in the maintenance plan rather than a series of emergency call-outs, internal make-good bills and tenant complaints.

If your building is showing early signs of sealant deterioration, if leaks are appearing at the window line after heavy rain, or if you simply do not know when the external joints were last replaced, a close-range condition survey is the logical first step. McPherson’s IRATA-certified rope access team delivers facade resealing, glazing assessment, height safety inspection and window cleaning across Melbourne’s CBD, bayside suburbs and metropolitan area, with full documentation at every stage. Call us today on 1300 30 15 40 to arrange an inspection and a scoped proposal for your building.