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Sub-frame constructions for ventilated facades

The benefits of working with Rockpanel boards extends to the flexibility of creating a two leaf construction for the external wall. This allows the ventilated air space between the two leaves to create and maintain a comfortable indoor climate.

(Ventilated) Wooden sub-frame

To ensure the correct application and a long-lasting installation to a wooden sub-frame it should be compliant to the following requirements:

  • Wooden frame constructions and timber battens fixed to a brick or concrete wall should be constructed according to BS EN 1995-1-1 and preserved according to EN 335 and BS 8417.
  • The wooden construction should be adequately supported to prevent deformation.
  • When wooden frames or battens are treated with wood preservatives, ensure that they are conditioned well before the exterior cladding is fixed.
  • The dimensions of the timber battens should be at least 28 x 70mm at the joints and 28 x 45mm at intermediate supports.
Ventilated sub-frame constructions with Rockpanel exterior cladding boards

(Ventilated) Metal sub-frame

To ensure the correct application and a long-lasting installation to an aluminium sub-frame it should be compliant to the following requirements:

  • The minimum thickness of the aluminium profiles is 1.5 mm.
  • The aluminium alloy is AW-6060 according to BS EN 755-2:
    - Rm/Rp0.2 value is 170/140 for profile T6
    - Rm/Rp0.2 value is 195/150 for profile T66
Ventilated sub-frame constructions with Rockpanel exterior cladding boards

Options for a ventilated construction

Construction with open joints

With an open construction, the horizontal joints should have a joint of a minimum 5mm. The vertical joints, with a minimum of 5mm are automatically closed by the backing of the vertical substructure. To ensure the durability of the wood, the vertical battens must be well protected against rain water. This can be done with a UV and weather-resistant EPDM foam tape that is 15mm wider on both sides than the framework. It can also be done with a strip of Rockpanel material, which acts as a gasket to protect the battens.

In a wooden construction, the structure behind the vertical batten should be protected with a breathable, water repellent and UV resistant membrane. The cavity between the Rockpanel boards and the membrane should be at least 28mm. When fixed with Rockpanel Tack-S on a Rockpanel strip the cavity should be at least 36mm (28mm thickness of batten plus 8mm of Rockpanel strip, according ETA). In a fire-safe construction with A2, fixed on an aluminium sub-frame, the cavity should be a minimum of 20mm. With an aluminium construction and open joints Rockpanel recommends a cavity depth of 40 - 100 mm. Application of corner cavity barriers is advised with open joints construction.

Ventilated constructions with open & closed joints with Rockpanel exterior cladding boards

Construction with closed joints

In a closed construction the horizontal joints are closed with a profile, usually a chair (Profile A) or nose profile (Profile B, semi-closed). This means that most of the rainwater is drained off from the outside of the exterior cladding. This structure still requires an air cavity of at least 28mm for timber sub-construction and at least 20 mm for metal sub-construction and a continuous opening of at least 5mm at the top and the bottom of the construction. The vertical joints are automatically closed by the backing of the vertical substructure. To ensure the durability of the wood, the vertical battens must be well protected against rain water. This can be done with a UV and weather-resistant EPDM foam tape. With a closed joint, the tape does not need to protrude. It can also be done with a Rockpanel strip.

Ventilated constructions with open & closed joints with Rockpanel exterior cladding boards
Rustenhove VZW with Rockpanel Colours in Ledegem, Belgium

A healthy indoor climate

Rockpanel boards are increasingly specified by architects and building managers who require a product which offers thermal, aesthetic and waterproofing benefits to ensure a healthy indoor climate in which people can live and work.

We manufacture board material mostly used in ventilated constructions, for facade cladding, roof detailing, soffits and fascias.