Repair Systems — 03
Window & Door Perimeter Failure
Technical product reference for epoxy timber repair, perimeter sealant systems, head flashings, storm angles, subsill drainage and balcony door hob systems for window and door perimeter water ingress in Class 2 strata buildings in Australia.
What are window and door perimeter repair systems?
Window and door perimeter water ingress is one of the most common defects in Class 2 strata facades in Australia. The interface between the window or door frame and the surrounding facade — whether rendered masonry, concrete or cladding — is a high-risk zone for water penetration. The four primary causes are: failed or missing perimeter sealant, missing or failed head flashings, absence of storm deflector angles on exposed facades, and failed or blocked subsill drainage. Each requires a different repair product and approach.
Perimeter sealant systems seal the joint between the window or door frame and the facade substrate, accommodating movement at this interface. Head flashings are installed above window and door heads to intercept and deflect water before it reaches the perimeter joint — they are a primary line of defence that sealant alone cannot replace. Storm deflector angles redirect driving rain and facade run-off away from perimeter joints on high-exposure or upper-level facades. Where the concrete or masonry sill or balcony door hob has deteriorated, the substrate must be reinstated with a polymer-modified repair mortar before new sealant can be applied.
AS 2047 establishes performance requirements for window installation and water penetration resistance. Correctly formed perimeter sealant joints must be installed over backer rod to control sealant depth and prevent three-sided adhesion. Before specifying any perimeter repair product, the actual failure mode must be diagnosed by inspection — just resealing the perimeter joint will not resolve water ingress caused by a missing head flashing or failed subsill drainage.
Do not confuse with:
- Full window replacement — perimeter repair systems address the frame-to-facade interface, not the window unit itself; a failed window unit requires replacement, not perimeter resealing
- Internal window reveals — plasterboard linings and internal reveal finishes are not part of the external waterproofing system
- Cavity wall flashings — flashings within the wall cavity at lintel level are a structural flashing, not a perimeter joint sealant; do not confuse cavity flashing repair with external perimeter sealant replacement
Product Reference
6 products — 5 brands — window and door perimeter repair systems — scroll to view all
System Description
Selleys Araldite Epoxy Putty is a two-part epoxy putty used for restoring and rebuilding deteriorated timber window sills, door frames and timber joinery on building facades. The two components are kneaded together by hand and applied to prepared timber surfaces, where it adheres firmly and cures to a hard, sandable and paintable mass that accepts all standard paint systems. In Class 2 strata remediation, epoxy putty repair is used where timber components show localised decay, checking or weathering damage that does not warrant full replacement — provided the surrounding timber retains structural integrity. The repaired area must be thoroughly primed and painted to prevent moisture re-entry. Confirm current Selleys product specification and suitability for exterior facade applications with Selleys technical before specifying.
Technical Properties
- Two-component epoxy chemistry — high bond strength to timber, masonry and most building substrates
- Hand-kneadable putty consistency — can be shaped and sculpted to replicate missing timber profiles before cure
- Sands and machines after cure — repaired area accepts standard primers and paint systems
Limitations
- Not a structural repair — epoxy putty restores profile and weather resistance only; underlying structural timber must be sound before application
- Two-component — working time is limited after mixing; large repairs require staged application
- Repaired area must be fully primed and painted — bare epoxy has limited UV resistance and will degrade if left exposed
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Description
Sikaflex-11 FC+ is a one-component moisture-curing polyurethane sealant widely used in Australian facade remediation for sealing window and door perimeter joints. Applied by cartridge gun directly into the prepared joint over backer rod or bond breaker tape, it accommodates movement at the interface between the window or door frame and the surrounding masonry, render or cladding substrate. In Class 2 strata remediation, Sikaflex-11 FC+ is specified for perimeter sealant replacement where existing failed or cracked sealant is allowing water ingress at window and door openings. Available in white, grey and standard colours. Paintable after full cure with compatible paint systems — confirm with Sika technical. Prime joint faces per current Sika TDS for best adhesion on porous or contaminated substrates.
Technical Properties
- One-component moisture-curing polyurethane — no site mixing required; reduces application error on facade perimeter joints
- Accommodates building movement at window and door frame perimeter joints — good elongation and recovery
- Paintable after full cure with compatible systems — confirm compatibility with Sika technical before applying paint coat
Limitations
- Backer rod or bond breaker tape required in all perimeter joints — prevents three-sided adhesion and maintains correct sealant depth ratio
- Do not apply to wet, damp or contaminated joint faces — adhesion failure at the substrate interface is the primary failure mode
- Not suitable for joints subject to continuous immersion without specific confirmation from Sika technical
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Lysaght Colorbond Head Flashing
Colorbond steel head flashing for windows and doors
System Description
Lysaght Colorbond head flashings are custom-profiled pre-painted steel flashings fabricated from Colorbond steel and installed above window and door heads to intercept and deflect water before it reaches the perimeter sealant joint. Head flashings are a primary line of defence against water ingress at window and door openings — particularly on rendered, masonry and concrete facade substrates exposed to driving rain. In Class 2 strata remediation, missing or failed head flashings are a common root cause of recurring water ingress at window and door heads that cannot be resolved by sealant replacement alone. The head flashing must be installed and correctly lapped into the facade system before the perimeter sealant joint is reformed. Confirm current Lysaght Colorbond product specification and colour range with Lysaght before fabricating.
Technical Properties
- Colorbond pre-painted steel — durable, corrosion-resistant and available in standard Colorbond colour range for facade integration
- Custom-profiled to suit window or door head and surrounding facade substrate — fabricated to project-specific dimensions
- Correctly installed head flashing protects the perimeter sealant joint from direct water loading — extends sealant service life
Limitations
- Custom fabrication required — confirm lead times and dimensions with Lysaght or local steel fabricator before specifying
- Correct installation critical — flashing must be lapped and bedded into the facade system to prevent water tracking behind the flashing
- Galvanic compatibility must be confirmed where flashing contacts aluminium frames or dissimilar metals — confirm with facade consultant
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Lysaght Aluminium Storm Angle
Aluminium storm deflector angle for window perimeters
System Description
Lysaght aluminium storm deflector angles are extruded aluminium profiles installed at window and door perimeters — typically at sill and jamb positions — to redirect driving rain and facade surface run-off away from the perimeter sealant joint and window frame interface. Storm angles are a secondary water management measure that reduces the volume and velocity of water reaching the perimeter joint. In Class 2 strata remediation, storm deflector angles are specified where facade geometry, wind exposure or building height creates high hydrostatic pressure on perimeter joints during storm events. Installation of a storm angle alone does not substitute for correct perimeter sealant and head flashing — it is part of a layered facade water management system. Confirm current Lysaght aluminium product specification and extrusion profile with Lysaght before specifying.
Technical Properties
- Extruded aluminium — lightweight, corrosion-resistant and compatible with most facade substrates without galvanic risk
- Deflects driving rain and facade run-off away from the window or door frame perimeter joint — reduces water loading on sealant
- Can be powder-coated to match window frame or facade colour — confirm coating compatibility with Lysaght
Limitations
- Storm angle reduces water loading on perimeter joints but does not substitute for correctly formed and sealed perimeter joints and head flashings
- Incorrect installation — insufficient lap over sealant joint or inadequate fixing — will allow water to track behind the angle
- Powder coat colour matching to window frames and facade finish must be confirmed before fabrication — custom colours may have lead times
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Sika Subsill Drainage
Subsill drainage system for window sill water management
System Description
Sika subsill drainage systems are proprietary drainage profiles installed below window frames to collect and redirect water that penetrates beneath the window sill, preventing it from entering the wall cavity or tracking down the internal facade surface. Subsill drainage is a component of a layered window water management system — intercepting water that bypasses the primary perimeter sealant and sill flashing. In Class 2 strata remediation, subsill drainage is specified where recurrent water ingress below window sills has been identified and where the window system geometry permits installation of a drainage profile. Confirm current Sika subsill drainage product specification, available profiles, and installation requirements with Sika Australia technical before specifying.
Technical Properties
- Intercepts water penetrating beneath the window frame and directs it to the face of the facade — prevents water entering wall cavity or internal substrate
- Proprietary drainage profile — designed to integrate with the window frame and surrounding facade system
- Durable polymer or aluminium construction — resistant to UV, moisture and facade cleaning chemicals
Limitations
- Subsill drainage is a supplementary measure — it does not substitute for correctly formed perimeter sealant joints and head flashings
- Installation requires access to the subsill area and may require partial removal of surrounding render or cladding — confirm scope with building consultant
- Confirm current Sika subsill drainage product range, available profiles and compatibility with window frame system before specifying
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
Renderoc HB40
Polymer-modified mortar for sill and hob repair
System Description
Renderoc HB40 is a polymer-modified cementitious repair mortar used for rebuilding and reinstating deteriorated concrete and masonry substrates including window sills, balcony door hobs and the masonry surrounds at window and door openings. Its polymer modification provides improved adhesion, flexibility and durability compared to standard site-mixed cementitious mortars. In Class 2 strata remediation, Renderoc HB40 is specified where window sill or door hob substrates have deteriorated through water ingress, carbonation or physical damage to the extent that the substrate cannot support a new sealant joint or flashing without reinstatement. The repaired substrate must be primed and sealed before applying perimeter sealant. Confirm current Parchem product specification and application requirements with Parchem technical before specifying.
Technical Properties
- Polymer-modified cementitious mortar — improved adhesion, flexibility and durability compared to standard cementitious mortars
- Suitable for rebuilding deteriorated window sills, balcony door hobs and masonry reveals at window and door openings
- Acceptable for vertical and overhead applications — thixotropic consistency reduces slump on vertical faces
Limitations
- Substrate preparation is critical — all loose, contaminated or deteriorated material must be removed before application; bond failure will occur if applied to a compromised substrate
- Reinforcing mesh or anti-fracture treatment may be required for large repair areas — confirm with Parchem technical
- Not a waterproofing membrane — repaired sill or hob must be waterproofed and sealed with compatible sealant and/or membrane after cure
PROCUREMENT SOURCES
Confirm suitability with the current manufacturer TDS before specifying or applying.
System Comparison
Side-by-side technical comparison of window and door perimeter repair products. Confirm current product specifications with manufacturer TDS.
| Product | Brand | Type | Material | Purpose | Install method | Primary use |
|---|---|---|---|---|---|---|
| Araldite Epoxy Putty | Selleys | Filler / repair compound | Two-part epoxy | Timber sill and frame reinstatement | Hand-knead and trowel apply | Restoring deteriorated timber window sills and door frames |
| Sikaflex-11 FC+ | Sika | Perimeter sealant | One-part PU | Seal window/door perimeter joints | Cartridge gun — over backer rod | Window and door frame perimeter joint sealing |
| Colorbond Head Flashing | Lysaght | Flashing | Colorbond steel | Deflect water at window/door head | Fixed mechanically — lapped into facade | Head water management at window and door openings |
| Aluminium Storm Angle | Lysaght | Water deflector | Extruded aluminium | Redirect driving rain from perimeter joints | Fixed mechanically to facade substrate | Perimeter water deflection at window and door sills/jambs |
| Sika Subsill Drainage | Sika | Drainage profile | Polymer / aluminium | Collect and redirect subsill water | Set into subsill — integrated with frame system | Below-frame water management at window sills |
| Renderoc HB40 | Parchem | Repair mortar | Polymer-modified cement | Reinstate deteriorated sills and hobs | Trowel apply to prepared substrate | Substrate reinstatement for window sills and balcony door hobs |
Brand Equivalents
Window and door perimeter repair system equivalents across brands active in Australian Class 2 strata remediation.
| System type | Sika | Lysaght | Selleys | Parchem |
|---|---|---|---|---|
| Perimeter sealant (window/door frame) | Sikaflex-11 FC+ | — | — | — |
| Head flashing (Colorbond) | — | Colorbond Head Flashing | — | — |
| Storm deflector angle (aluminium) | — | Aluminium Storm Angle | — | — |
| Timber frame repair | — | — | Araldite Epoxy Putty | — |
| Sill/hob repair mortar | — | — | — | Renderoc HB40 |
Diagnose before specifying
- Window water ingress has multiple causes — failed perimeter sealant, missing or failed head flashing, no storm deflector angle, failed subsill drainage, or membrane failure above the opening. Resealing the perimeter joint alone will not fix a missing head flashing.
- Engage a building consultant to diagnose the actual failure mode before specifying any repair product — incorrect specification wastes cost and leaves the defect unresolved.
- Head flashings are a primary line of defence — where head flashings are missing or failed, they must be installed before perimeter sealant is replaced. Sealant is not a substitute for flashing.
- Confirm window system compliance with AS 2047 as part of the investigation — a non-compliant window installation may require full replacement of the window unit, not perimeter repair.
Disclaimer
Information is general only. Window and door perimeter repair specifications must be confirmed against window type, frame material, substrate and the current manufacturer technical data sheet. Water ingress at windows may indicate failed flashing, failed sealant, or structural settlement — engage a building consultant to diagnose before specifying repair. Do not rely on this reference as a substitute for professional advice.