Flashing and Weatherproofing Requirements for Windows and Doors

What This Requirement Covers

This requirement governs the design, selection, installation and verification of flashing and weatherproofing for windows, glazed doors and external doors to prevent water ingress that could cause unhealthy conditions, loss of amenity or deterioration of building elements. It brings together the National Construction Code (NCC) performance requirements for weatherproofing with the Deemed-to-Satisfy provisions and referenced Australian Standards that describe tested windows, installation detailing and membranes. The requirement applies to designers, builders, certifiers and homeowners responsible for specifying or installing window and door assemblies on external walls.

The purpose is to ensure external openings are constructed and terminated so that rainwater and driven wind-driven water do not penetrate the building envelope. Compliance is required where the NCC F3 (Volume One) or H2 (Volume Two for housing) weatherproofing provisions apply, and to glazed assemblies that must comply with AS 2047 (or other glazing provisions described in NCC Volume Two). It therefore applies to most Class 1-9 buildings except where the NCC expressly limits the application (for example some Class 7 or 8 situations and minor outbuildings where weatherproofing is not necessary).

Key Requirements

1. Performance requirement: External walls (including openings around windows and doors) must prevent water penetration that could cause unhealthy or dangerous conditions, loss of amenity or undue dampness or deterioration of building elements (NCC Volume One, Part F3 - F3P1; NCC Volume Two H2V1/H2P2 for Class 1/10 housing).
2. Tested windows and glazed assemblies: Windows, sliding and swinging glazed doors with a frame, adjustable louvres, shopfronts and window walls must comply with AS 2047 requirements for resistance to water penetration where the NCC requires it (NCC Volume One, F3D4; NCC Volume Two guidance referencing AS 2047).
3. Verification by prototype testing: Compliance with weatherproofing for an external wall may be demonstrated when a prototype passes the specified test procedure (including representative samples of openings, joints, wall junctions, window/door assemblies, control joints and terminations) and the wall meets the NCC risk and wind limitations (see NCC Volume One F3V1 and NCC Volume Two H2V1). The prototype test specimen must include features such as vertical and horizontal control joints, windows or doors, balcony drainage and header/footer termination systems (NCC Volume One F3V1(2)-(3); NCC Volume Two H2V1(2)-(3)).
4. Wind limits for the simplified verification: The prototype verification route for weatherproofing in F3V1 and H2V1 applies only where the external wall is not subjected to an ultimate limit state wind pressure greater than 2.5 kPa and the wall has a risk score of 20 or less determined from the relevant table (NCC Volume One F3V1(1)(b)(ii)-(i); NCC Volume Two H2V1(1)(b)(ii)-(i)).
5. Glazing and window design standards: Use windows that comply with AS 2047 for water penetration resistance and AS 1288 or Part 8.3/8.4 of the ABCB Housing Provisions where those clauses apply (NCC Volume Two explanatory information and clauses specifying which glazed assemblies must meet AS 2047 or AS 1288).
6. Sarking and membrane materials: Sarking-type materials used for weatherproofing of roofs and walls must comply with AS 4200.1 and AS 4200.2 (NCC Volume One F3D3). External waterproofing membranes for roofs must meet F3D2 requirements and the referenced Australian Standards (NCC Volume One F3D2).
7. Cavity wall and terminations: Test specimens for verification must include cavity details and require internal inspection provisions (e.g., transparent internal lining proportion and a 15 mm diameter hole in internal lining below a window for cavity walls in test specimens) to assess leakage paths (NCC Volume One F3V1(3)(b)(i)-(ii); NCC Volume Two H2V1(3)(b)(i)-(ii)).
8. Scope limits for glazed assemblies: Certain glazed assemblies are excluded from AS 2047 requirements where noted (e.g., glazing not in external walls, revolving doors, fixed louvres) and some building classes (Class 7 or 8 where not necessary) are exempted from F3P1 (NCC Volume One F3D4(2)-(3); F3P1 Limitations).
9. Referenced Australian Standards and guidance commonly used:
10. AS 2047 - Windows in buildings (design, testing and manufacturing requirements for water penetration resistance).
11. AS 1288 - Glass in buildings - Selection and installation (where glazing is at risk of human impact or other specific cases referenced in NCC Volume Two).
12. AS 4200.1 / AS 4200.2 - Sarking and building underlays: product and installation requirements for wall and roof underlays used for weatherproofing (NCC Volume One F3D3).
13. Other related standards often referenced by practitioners for detailing: AS 4285 (roofing and wall flashing guidance where applicable), AS 4654.2 (waterproofing membranes for external above-ground use) and the ABCB Housing Provisions (Part 8 series) for prescriptive glazing/installation methods.
14. Code references (examples to cite in documentation):
15. NCC Volume One, Part F3 - Roof and wall cladding (F3O1 Objective; F3P1 Weatherproofing; F3D3 Sarking; F3D4 Glazed assemblies; F3V1 Verification method).
16. NCC Volume Two, H2V1/H2P2 Weatherproofing for Class 1 and 10 buildings (prototype test procedure, AS 2047 references) and explanatory information referencing Part 8.3 of the ABCB Housing Provisions.

Residential vs Commercial

1. Residential (Class 1 and 10 - NCC Volume Two / ABCB Housing Provisions):
2. Glazing and windows in typical housing must comply with AS 2047 for water penetration resistance if they fall within the conditions described in NCC Volume Two (or comply with Part 8.3/8.4 of the ABCB Housing Provisions as the Deemed-to-Satisfy path). The prototype test verification and risk scoring method in H2V1 applies for external wall systems used in housing.
3. Prescriptive details in the ABCB Housing Provisions often provide specific installation methods for head, jamb and sill flashings for common window types in housing, and AS 4200 sarking is commonly prescribed.
4. Commercial (Class 2-9 - NCC Volume One):
5. The performance requirement F3P1 applies and the Deemed-to-Satisfy/verification methods in Volume One apply. Commercial glazing assemblies frequently require design-tested window systems complying with AS 2047; larger or bespoke shopfronts, curtain walls or window walls may require specialist tested systems, project-specific verification, and cannot rely on simple housing details.
6. Higher wind-load or exposure conditions, or complex building geometries, will typically fall outside the simplified prototype verification limits (e.g., wind pressures > 2.5 kPa) and will need specific engineering design, water penetration testing to project wind pressures, or other verification routes.

Exceptions and Exemptions

1. Class 7 or 8 buildings: F3P1 does not apply where there is no necessity for weatherproofing for that particular building (NCC Volume One F3P1 Limitations).
2. Certain glazed assemblies: Glazed elements not in an external wall, revolving doors and fixed louvres are excluded from the AS 2047 requirement described in F3D4(3).
3. Prototype test limitations: The simplified prototype verification in F3V1/H2V1 is limited to walls with a risk score of 20 or less and ultimate limit state wind pressure not greater than 2.5 kPa. Where these limits are exceeded an alternative verification method or full testing to project conditions is required.
4. Acceptable alternatives: Where prescriptive Deemed-to-Satisfy details are not practicable, compliance may be shown by performance-based design, specific testing to project pressures (often using AS/NZS test methods referenced in AS 2047) or using manufacturer-supplied tested systems and certificates showing compliance with AS 2047 for the intended conditions.

State and Territory Variations

1. The NCC is a national code but each state and territory may have schedules or amendments that modify national provisions or add requirements. Practitioners must check the relevant state schedules in NCC Volume One Schedules (Schedules 4-12) for modifications. Examples to consider:
2. Queensland: Schedule 7 of NCC Volume One may contain state-specific amendments affecting weatherproofing or glazing requirements in cyclonic or coastal zones - verify against the Queensland schedule.
3. New South Wales/Victoria/Tasmania/Australian Capital Territory/South Australia/Western Australia/Northern Territory: Each jurisdiction may adopt additional planning or construction requirements (for example, additional energy, heritage or bushfire measures) that affect window selection or installation. Always consult the state schedule in NCC Volume One and local authority requirements.
4. Note: Wind region, terrain and height limitations under AS 4055 and local planning controls will affect whether a window system tested to AS 2047 is suitable; different states may enforce additional testing or certification for coastal, cyclonic or high-wind regions.

Practical Compliance Tips

1. Use AS 2047-tested window systems for external windows and glazed doors where the NCC requires it, and keep manufacturer test certificates on file showing the product was tested to the project wind pressures and water penetration requirements.
2. Follow sarking and underlay standards: specify and install wall sarking and underlays that comply with AS 4200.1/AS 4200.2 and ensure laps, terminations and junctions are sealed as the product data sheet and NCC Deemed-to-Satisfy details require.
3. Detail head, jamb and sill flashings for each window and door: use purpose-made head flashings, sill flashings with effective outflow, and jamb flashing/adhesive membranes to create a continuous drainage plane from the frame to the outside; mirror the tested manufacturer details where possible to maintain tested performance.
4. Control joints and junctions matter: include representative junction details (control joints, wall penetrations, parapets and balustrade junctions) consistent with the tested system or Deemed-to-Satisfy details. Poorly detailed junctions are the most common source of leaks.
5. Don’t assume one-size-fits-all for wind loads: check the design wind pressure for the building location and height (AS 1170.2 / AS 4055 where applicable). If ultimate limit state wind pressure exceeds 2.5 kPa, do not rely on simplified prototype verification - use tested systems rated for the project wind pressure or project-specific testing.
6. Keep records and installation instructions: retain manufacturer installation guides, test reports and certificates showing compliance with AS 2047 (or other applicable standards) and ensure installers follow the tested installation details exactly.
7. Check local variations and council requirements early: review the relevant state schedule in NCC Volume One and local authority requirements before finalising window/door selections; coastal, cyclonic or heritage overlays commonly change acceptable products or installation details.

Citations (key NCC references used above)

1. NCC 2022 Volume One, Part F3 - Roof and wall cladding (F3O1 Objective; F3P1 Weatherproofing; F3D3 Sarking; F3D4 Glazed assemblies; F3V1 Verification method).
2. NCC 2022 Volume Two, H2V1/H2P2 - Weatherproofing and verification for Class 1 and 10 buildings (references to AS 2047 and prototype testing provisions).