Determinations issued
Determination 2005/145
Refusal of a code compliance certificatefor a house with a 'monolithic' cladding system
The application arose from the territorial authority's refusal to issue a code compliance certificate for an 11-year-old house unless changes are made to its monolithic cladding system.
The two specific matters determined were whether:
- the external cladding as installed on this building complies with Clause E2 of the Building Code
- after considering the elapsed time since construction, certain building elements comply with Clause B2 of the Building Code.
The building
The building is a two-storey detached house, with a developed garage and lobby basement area.
The house shape is fairly complex, with pitched roofs at varying levels and numerous hip, valley and wall-to-roof junctions. Generally the eaves have 450 mm wide projections, but there are minor locations without projections.
The external walls are constructed from borate-treated light timber frame on concrete block foundation and retaining walls, or timber-framed floors. The walls are sheathed with monolithic cladding.
The cladding system is what is described as monolithic cladding, and is a 7.5 mm thick 'Harditex' system fixed directly to the framing over a building wrap, and finished with an applied textured system.
The building is located on an excavated sloping site, in an undetermined wind zone.
Issue 1: The cladding
The Department engaged an independent expert to undertake an inspection and report.
The expert stated that the finish of the textured surface was regular and consistent and that the paint film was uniform and in reasonable condition. However, there was evidence of some locally touched-up areas.
The expert investigated the jambs and sills at three randomly selected windows and found that these were sealed but not flashed.
Generally, the cladding appeared to be installed according to reasonable trade practice, but some junctions, edges and penetrations were not well constructed. These areas were the:
- wall of the building that is of a height to require a horizontal control joint
- minor cracking adjacent to the window frames and in the face of the cladding at some locations
- inadequate clearance to the base of the cladding adjacent to the paving at some locations
- head flashing over the French doors to the main bedroom being cut flush with the window jamb
- lack of jamb or sill flashings to the exterior joinery units
- poorly finished cladding at the junction with the head flashings of the exterior joinery units at some locations
- fascia/gutter above the garage door being embedded in the cladding and the lack of an end 'kick out' to the apron flashing at this location.
The expert accepted that the details exposed by these inspections are representative of other similar locations throughout the building.
The compensating factors to assist the performance of the cladding were that the:
- cladding appeared to have been installed according to reasonable trade practice
- house has 450 mm wide eaves that provide some protection to the cladding areas below them
- house has external wall framing that is treated to a level that would help prevent decay if it absorbs and retains moisture.
Issue 2: The additional durability considerations
The territorial authority had concerns about the durability of certain elements of the building, and hence compliance with the Building Code, with consideration that the building was completed in 1994.
Those elements were the:
- cladding, including flashings, excluding items of rectification noted in the determination
- pressed metal roofing
- deck membranes
- wet area membranes
- particle board flooring in wet areas
- external gutters and downpipes
- shower linings.
Decision
The monolithic cladding allowed water penetration into the building in at least one location. Consequently, the cladding system as installed failed to comply with Clause E2 External Moisture of the Building Code.
In addition, the building must comply with the durability requirements of Clause B2. The faults in the installed cladding system had allowed water ingress, and will allow moisture ingress in the future. Accordingly, it did not comply with the durability requirements of Clause B2 of the Building Code.
The determination ruled that the territorial authority must amend the original building consent to incorporate a waiver of Clause B2 of the Building Code. The waiver must be of the effect that the required durability periods for certain elements are measured from the date of the substantial completion of the building and not from the date of the issue of a code compliance certificate.
For the purposes of this determination, substantial completion was defined as being when the building was completed and ready for occupation.
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