Rainscreen cladding is generally defined as panels that are individually supported and restrained allowing construction to take place with open joints. Differential movement is accommodated in each joint, which negates the need for larger compression and expansion joints. Open jointed systems provide a ventilated cavity and require waterproof rainscreen insulation systems. Ventilated cavities assist in achieving the demands of the new European energy saving requirements.
CONCEPT
The essentials of a Rainscreen system are to allow the ingress of air at the base of the system and the egress of air at the top of the system. This ventilated cavity allows any water which penetrates the panel joints to be partly removed by the ‘stack effect’ and partly removed by running down the rear face of the panels and out of the base.
FACADE ENGINEERING
As part of a comprehensive technical support service, Hal Mann Vella can provide assistance for the safe and optimised setting out of the grid system through the preparation of ‘project specific’ static calculations. These calculations determine the engineering requirements of the façade, hrough the most practical and economical use of the system components. On most projects appearance, suitability, availability and cost are likely to be the etermining factors. Ideally the stone or engineered materials selected will be the most appropriate for the application, readily available, produced to the required tolerances and within budget. In all instances detailed research should be underken to establish the technical competency of the stone at an early stage.
PRINCIPLES
- A Rainscreen system consists of an outer panel, a ventilated cavity, and an inner leaf.
- In driving rain conditions moisture forms a membrane across the baffled vertical and horizontal joints.
- The majority of water is deflected off the outside face – any penetrating water is disposed of through drainage.
- Rainscreen systems differ from wall sealed construction as the beneficial effects to air movement are utilised.
- A Rainscreen system is a pressure equalised – the joints are open or lightly baffled, allowing pressure equalisation in driving rain conditions to be instantaneous. The pressure inside the cavity is equal to pressure outside – ie, precipitation has no inclination to be driven into cavity
- A continuous vertical-cavity – At least 30 mm deep
APPLICATIONS
- Wall cladding and facade finishes
- Fascias and soffits
- Column covers
- Balcony and canopy cladding
- Stairways and lifts
- Roof edgings and parapet wall copings
ADVANTAGES
- Installation is simple – allowing external cladding and internal works to proceed speedily, early and consecutively.
- Problems of deterioration are halted with minimal additional load being applied to the existing structure.
- Aesthetic colour, flexibility and shape of external facade may be dramatically altered.
- Energy saving – lower running costs due to greatly improved thermal insulation.
- Easily removed panels for monitoring of structure.
- Reduction of the risk of condensation due to the elimination of cold bridges
