The Applicant proposes to apply Sealit multipurpose waterproofing compound to external brick walls in lieu of installing sill and head flashings to the as-built window openings.
In addition, the Applicant proposes to apply Crommelin Hybrid MS Polyurethane Sealant to fill gaps between window openings and external walls, in lieu of installing sill and head flashings to the as-built windows.
The Applicant maintains that the application of these two waterproofing products to external brick walls and around window openings, to the manufacturers' specifications, will provide a weatherproof barrier to prevent moisture ingress from around external window frames.
[2]
We are not persuaded that the Applicant's proposal addresses the performance requirements of cl 5.7.4(3) of the HPS 2022, which is designed to ensure proper water drainage and to prevent water ingress into the wall cavity.
What is provided in cl 5.7.4(3) ensures that water is directed away from openings to prevent moisture damage to the building by returning flashings into the wall cavity, fixing head flashings to window frames and embedding sill flashings into brickwork.
Approved head and sill flashings, installed correctly, are robust and designed to direct water away from the wall cavity and out of the building structure.
We find that the Applicant's proposal will not ensure proper water drainage but has the potential to seal moisture into cavity areas of the building, as water ingress may occur via areas other than from brick wall penetration or from gaps around window frames. Water ingress to the wall cavity may be from roof or gutter areas, for instance.
We are of the opinion that wall opening flashings as per the HPS 2022 are a robust and effective measure to prevent the retention of moisture within the fabric of a building, and their installation is a well-known mandatory requirement for best building practice.
Cases Cited (1)
�In the Matter of 68 Dargile Circuit, Epping [2025] VBAB 94; (14 July 2025)