Changes to The National Construction Code – Window Flashings




At Southern Star Group we take great pride in providing our customers with relevant industry information so that they can be aware of legislative changes relating to the construction of dwellings.


The National Construction Code (NCC) of 2019 was published earlier this year (February 1st) and, subject to state and territory transitional processes, this was adopted in May 2019. There are many things that have changed in relation to the industry as a whole, but in regard to the window industry specifically, there are new provisions regarding  weatherproofing of openings and, in particular, flashings to windows and doors. Two new Acceptable Construction Practices (ACP’s) provide guidance for masonry veneer, and light-weight (clad) construction.





The requirements for masonry veneer construction detailed in Clause stipulate flashings must be fitted to the top and bottom (head and sill) of an opening and;


(i)        installed so that the flashing extends a minimum of 150 mm on each side of the opening,

(ii)       located no more than one course below the sill brick course; and 300 mm above the opening,

(iii)      turned up in the cavity not less than 150 mm above the opening,

(iv)       embedded at least 30 mm into the masonry veneer, and

(v)        attached to the window or wall framing.




Clause requires that flashing must be provided to the tops, sides and bottoms (head, jamb and sill) of an opening and;

(i)        extend at least 110 mm on each side of the opening,

(ii)       be attached to the window and wall framing, and

(iii)      drain to the outside face of the wall or cladding at the top and bottom of the opening, and

(iv)       be securely fixed at least 25 mm under the cladding and extend over the ends and edges of the framing of the opening.


Joins in the flashing must


(i)        overlap by not less than 75 mm in the direction of flow,

(ii)       be securely fastened at intervals of not more than 40 mm,

(iii)      have sealant installed between laps.



In both construction types, head flashing may be omitted where the top of the opening is protected by an eave or roof that extends more than 3 times the distance from the top of the opening to the underside of the eave, or where W is no less than 3 x H in the below image


Images courtesy of The Australian Glass and Window Association (AGWA).

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