Tips & Innovations

Cavity Batten for Vertical Shiplap Cedar

Vertical shiplap cedar cladding is a bold statement. Its verticality alone adds a dramatic aspect to any facade, while the natural variants of Cedar have long made this a popular choice for cladding. Limitations in the Building Code around its use have led to a rapid development of this cladding type as an Alternative Solution.

Within the Building Code there is no provision for use of a horizontal cavity batten because of the risk of moisture getting trapped behind the cladding and having no point of egress. Over the past 15 years, this restriction has led to the development and testing of cavity systems to overcome this limitation and meet the ever increasing demand for this cladding type. If you want to use a horizontal batten, you must have it tested and approved as part of a cladding system as an Alternative Solution.

Restrictions in the use of vertical cladding have all changed with development of ventilated cavity batten systems. Rosenfeld Kidson’s CodeMark certified 45mm cavity batten system is a further progression, improving performance and broadening the range of applications where it can be used, including the Extra High wind zone

Standard horizontal cavity battens are 20mm thick, which means that the weatherboards are face-nailed through the weatherboard, through the batten, through the building underlay and into the framing behind. Long nails are needed - either 75mm with a flexible underlay or 85mm with a rigid underlay and Silicon Bronze or Stainless Steel are used, which are relatively soft materials and can leave room for error in fixing, being easy to skew and miss the framing. This can create a pathway for moisture to travel from the cladding face to the underlay. 20mm battens also require additional framing for support, practically doubling the number of nogs/dwangs required.

With the 45mm system, the batten is tested and designed with radiused grooves to improve the strength of the section so the batten can span the studs. It therefore does not require any additional framing for support. You are then able to replace this additional wall mass of timber framing with insulation, adding to the walls R-value. It’s also more durable with a 50-year minimum lifespan compared to a 15-year durability requirement for 20mm battens.

The battens are fixed to the framing and then the weatherboards are fixed with shorter 60mm nails directly to the battens alone, with no need to puncture the building underlay with face fixings. This helps to maintain the integrity of the underlay so the cavity can remain pressure equalised, which is the best way to prevent moisture being drawn into the cavity. If moisture does enter the cavity, the batten is designed with a bevel to the top and has a drip edge to the bottom corner to direct water to the back of the weatherboards, away from the underlay and out of the base of the cavity.

These thicker battens have led to increased scope in other areas and Rosenfeld Kidson now offer a Recessed Window Flashing System. This allows the aluminium window joinery to be pulled back to the frame and flashing line. The opening is clad around and into, to create a minimum 65mm recess.

This new solution improves thermal and weather-tightness performance while achieving a clean and contemporary look.


Download RKV45-BATT Details



Download RKV45-FU-53 Details

Recessed Window System

Rosenfeld Kidson can now offer its INTERSET Recessed Window Flashing System for vertical timber cladding.? The system comprises of a set of aluminium flashings and thermoplastic stop-ends that interlink to form a picture-framed window recess…




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