DriSpace Vented Roof and Wall Pre-Cladding Systems

Understanding the science behind buildings and the use of the right pre-cladding products and systems will ensure a more energy-efficient building envelope and a dry building.

NZ has been focusing on heating, insulating, double glazing, roofing underlays and energy efficiency. Ventilation of non-habitable spaces has largely been ignored which has resulted in internal moisture and condensation issues. DriSpace vented roof and wall systems apply the basic principle of “If you heat and insulate, but don't ventilate, you will condensate.”

To get ventilation of metal roofs right, a minimum two out of three key factors below must be considered:

High vapour permeable underlay (preferably with drainage and ventilation above the underlay)
Adequate passive ventilation
Vapour tight ceilings

DriSpace Residential Literature provides solutions to different roofs, including longrun trussed roofs, longrun skillion roofs and tiled roofs. It is an easy-to-follow guidance for architects, designers and contractors and is available for free download on the DriSpace website.

Let’s have a look at one of the DriSpace systems for residential buildings: a trussed roof design with roof pitch less than 30°C.

Roof: Over fascia vents, G1200N or G2500N are installed at the eaves to introduce airflows into the roof cavity, and G502 Roll Rafter Tray is installed to ensure airpath is created and not blocked by the ceiling insulation. DriStud synthetic roof underlays with vapour resistance of less than 0.5MNs/g are installed to provide sufficient vapour permeability. 10mm vented battens are installed between the longrun roof and underlay to provide ventilation and drainage of moisture from dew point condensation.
Wall: DriStud Wall Wrap with high vapour permeability and water resistance is installed with the DriStud Cool Window Flashing Tape. Then vented battens, VB20, are used as non-structural cavity battens. There are a number of sealants independently tested with Cool Window Flashing Tape and the list is available on the DriSpace website and Masterspec.

There is a specification code for each system and design in the DriSpace Residential Literature. Just use the specification code and all the system components are automatically specified together. It is a simple and easy way to specify systems which eliminates any unnecessary mistakes of missing out some products.

DriSpace also offer system solutions to cold roof ventilation and walls for schools for both new builds and re-roofs in accordance with updated MOE design requirements. MOE design recommends warm roofs for schools and DriSpace supports the recommendations. In fact, they have been working with warm roof manufacturers, and there are a number of DriSpace products used, including DriStud Roof Underlays and Cool Window Flashing Tape.

For cold roofs, the MOE design requirements include a vapour control layer to make the ceiling vapour tight. Install Proctor SmartVap 100 above the ceiling plasterboard and DriStud FRU38 roof underlay draped over rafters and under a counter batten. Or alternatively you can install DriStud FRU38 on the purlins, then install 10mm vented battens VB10 between the steel longrun and underlay to provide ventilation and drainage above the underlay.

Please contact the DriSpace technical team to get system solutions on: [email protected]
Or contact Jinny Kim on 021 935 555 email: [email protected]

DriStud FRU38 — Fire Retardant Synthetic Self-Support Roof Underlay

DriSpace

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DriStud FRU38 is a white synthetic tri-laminate roofing underlay that is water resistant, vapour permeable and fire retardant.

DriStud FRU38 is intended for use on buildings designed in accordance with NZS 3604:2011 paragraph 1.1 and in wind zones up to and including 'Extra High'.
DriStud FRU38 is designed to be used as a replacement for standard kraft paper roof underlay.
It can be installed over both timber and steel framing to ensure a dry roof cavity.
DriStud FRU38 can be used under: masonry tiles, metal tiles, profiled metal roof claddings.

Where CodeMark is to be relied upon, then all conditions of that certificate must be met. These are:

Must be installed in accordance with the DriStud FRU38 Installation Guide Rev 1.
DriStud FRU 38 may be installed over timber and steel roof framing.
The certificate covers the use of DriStud FRU 38 under: masonry tiles, terracotta tiles, metal tiles, profiled metal claddings, slate and composite panels.
DriStud FRU38 can span up to 1200mm between adjacent supports. Where the span exceeds 1200mm a corrosion resistant mesh or alternative i.e. plastic strapping must be used.

When specified and installed in accordance with the requirements of the Installation Guide, DriStud FRU 36 roofing underlay will comply with the following provisions of the NZ Building Code:

Clause B1 Structure: B1.3.1, B1.3.2, B1.3.3 (a, h)
Clause B2 Durability: B2.3.1(a), B2.3.2(b) (15 years)
Clause C Protection from Fire: C3.4(c)
Clause F2 Hazardous Building Materials: F2.3.1

CodeMark

ProctorPassive SmartVap

DriSpace

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ProctorPassive SmartVap is a two layer AS/NZS 4200.1 compliant light duty air barrier and variable vapour diffusion resistance retarder.

Designed for effective management of air and vapour passage through wall, ceiling and floor assemblies
Can help protect the building fabric and insulation from condensation and related problems such as mould, timber rot, corrosion and loss of thermal resistance
When installed as a continuous layer, SmartVap will form an air tight layer, improving the efficacy of ventilation systems and thermal efficiency of the building enclosure

Two layer AS/NZS 4200.1 compliant

DriStud Wall Wrap

DriSpace

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DriStud Wall Wrap is engineered from resilient non-woven fabric and is a commercial grade building wrap.

DriStud Wall Wrap is intended for use on buildings designed in accordance with NZS 3604:2011 paragraph 1.1 and in Wind Zones up to and including ‘Very High’.
It may be installed over timber and steel framing.
Where DriStud Wall Wrap is to be installed over steel framing it is important to ensure an adequate thermal break has been installed.
DriStud Wall Wrap may also be used in conjunction with the following substrates:
- Oriented strand board
- Concrete
- Fibre cement
- Plywood
DriStud Wall Wrap may be used where the external cladding is direct fixed or over a nominal 18mm ventilated cavity as per table 3, E2/AS1.
The scope of the CodeMark certificate covers the use of DriStud Wall Wrap in buildings:
- up to 10m in height, and
- with a risk score less than 20, when evaluated against the E2/AS1 risk matrix, and
- up to and including very high wind zone as defined i in NZS 3604:2011, and
- in all corrosion zones as defined in NZS3604:2011.
The scope of the certificate covers the use of DriStud Wall Wrap with DriStud Cool Window Flashing Tape, DriStud Bozz Window Flashing Tape and rigid air barriers made from plywood, OSB or fibre cement.

Oriented strand board
Concrete
Fibre cement
Plywood

up to 10m in height, and
with a risk score less than 20, when evaluated against the E2/AS1 risk matrix, and
up to and including very high wind zone as defined i in NZS 3604:2011, and
in all corrosion zones as defined in NZS3604:2011.

When specified and installed in accordance with the requirements of the Codemark Certificate, DriStud Wall Wrap will comply with the following provisions of the NZ Building Code:

Clause B1 Structure: B1.3.1, B1.3.2, B1.3.3 (a, c, q), B1.3.4 (a, b, c, d, e)
Clause B2 Durability: B2.3.1 (b), B2.3.2 (a)
Clause C Protection from Fire: C3.4(c)
E2 External Moisture: E2.3.2, E2.3.7 (a, b, c)
Clause F2 Hazardous Building Materials: F2.3.1

CodeMark

DriStud Cool Window Flashing Tape

DriSpace

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DriStud Cool Window Flashing Tape is a window sealing system that can also be used for general sealing of wall penetrations.

DriStud Cool Window Flashing Tape is intended for use in new and existing buildings in conjunction with an underlay or rigid air barrier.
It is used around framed joinery openings and penetrations, providing a secondary weather resistant barrier.
It is designed to be used in conjunction with air seals and joinery flashing systems, but not as a substitute.
DriStud Cool Window Flashing Tape may also be used at joinery heads to seal flashing upstands to the building wrap.
Where a rigid underlay has been installed, DriStud Cool Window Flashing Tape may be used to seal all junctions and penetrations.
It is suitable for use with timber and steel framed buildings as well as masonry structures.
It may be used where the environmental temperature fluctuates between -25ºC and 80ºC.
Must be installed in accordance with the DriStud Cool Window Flashing Tape Installation Manual Rev 1, July 2015.
The scope of the CodeMark certificate covers the use of DriStud Cool Window Flashing Tape in buildings:
- up to 10m in height, and
- with a risk score less than 20, when evaluated against the E2/AS1 risk matrix, and
- in wind zones up to extra high as defined in NZS 3604:2011, and
- in all corrosion zones as defined in NZS3604:2011.

up to 10m in height, and
with a risk score less than 20, when evaluated against the E2/AS1 risk matrix, and
in wind zones up to extra high as defined in NZS 3604:2011, and
in all corrosion zones as defined in NZS3604:2011.

When specified and installed in accordance with the requirements of the CodeMark Certificate, DriStud Cool Window Flashing Tape will comply with the following provisions of the NZ Building Code:

Clause B1 Structure: B1.3.1, B1.3.2, B1.3.3 (a, c, q), B1.3.4 (a, b, c, d, e)
Clause B2 Durability:B2.3.1 (b), B2.3.2 (a)
Clause E2 External Moisture: E2.3.2, E2.3.7 (a, b, c)
Clause F2 Hazardous Building Materials: F2.3.1

CodeMark

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