Part 8:Panels for outdoor walls

HPL-Compact can be used to install a wide range of outdoor applications, such as façade panels, balcony dividing walls, roof soffits, carports, fences and outdoor furniture. The local building regulations have to be observed.

Planning façades and façade components
Façades have to be planned by a certified professional. Particular attention has to be given to correct arrangement, dimensions and type of the substructure, arrangement and type of the panel fastening as well as the climatic conditions during subsequent use. Climate-related expansion behaviour of the substructure and of the HPL-Compact will differ. For metal substructures, the temperature-related length change plays a greater role, while the moisture- related length change is more relevant for HPL-Compact. For HPL-Compact, the climate-related expansion behaviour in crosswise direction (width of available formats) is about twice the expansion in lengthwise direction (length of available formats). Joints between sheets should be at least 8-10 mm. Edge distances between drill holes (usually at least 20 mm) must be observed for structural reasons. The local requirements (e.g. wind loads, building height) have to be taken into account when selecting the spacing between fasteners.

Substructure
Substructures – usually metal-based – are available for façades with rear ventilation. Their properties as well as the necessary fastening points have   to be considered for façade planning. Substructures with rear ventilation can also be made out of wood with battens or using battens and counter battens. Elastic sealing strips have to be applied to ensure that the wooden structure behind is protected against moisture. Depending on the surface area, attaching balcony panels have to be clarified individually, as there are many different options such as U-profiles, L-profiles or glass holder systems.

Fasteners for HPL-Compact
Countersunk and oval-head screws are generally not suitable for installing HPL-Compact. For all fastening types, it has to be taken into account that temperature and humidity changes can cause the HPL surfaces to expand and contract and that swelling (< 0.3 mm) do not cause unusual tensions. Therefore, e. g. screws should be tightened finger-tight or rivets should be placed with a rivet setting gauge. The diameter of the drilled holes is generally 2 mm larger than the shaft diameter of the screws or rivets, except for fixing points. Various other fastening systems are available on the market. It has to be individually clarified whether a planned structure complies with all legal requirements and the state of the art. The manufacturer's specifications and the requirements of the approvals must be observed.

Stainless steel screws
The diameter of the screw heads has to be at least 4 mm larger than the drilled hole. They can be painted or colour-matched with cover caps. The shaft thickness of the screws has to be at least 5 mm and has to be adapted to the requirements.

Aluminium or stainless steel rivets
The diameter of the rivet heads has to be at least 6 mm larger than the drilled hole. They can be painted or colour-matched with cover caps. The shaft thickness of the rivets has to be at least 5 mm and has to be adapted to the requirements. The rivets have to be installed with a gauge to reduce the contact pressure and ensuring the expansion gap.

Glass holders
Depending on the requirements, glass holders can also be used for installing
HPL-Compact, e. g. clamping elements with locking pin.
 

Profiles (wood, metal or plastic systems)
Depending on the design and requirements, HPL-Compact can also be installed using window profiles, U-profiles or L-profiles. In addition to the strength requirements, it has to be taken into account that there is sufficient space for climate-related dimensional changes and loading / unloading openings. Seals on the HPL surface are ideally implemented with rubber seals.

Bonding systems
For bonded façade elements, the processing instructions from the adhesive and installation tape manufacturers must be observed. Sufficient space for climate-related dimensional changes has to be ensured for this system as well.

Concealed fasteners
Undercut anchors, threaded inserts (screwed inserts) or self-tapping screws and clamps can be used for concealed fastening of façade panels. The requirements for the elements (wind load, supporting strength, etc.) have to correlate to the strength properties (pull-out force) of the anchors or inserts and their spacing. The manufacturer’s instructions for use have to be observed.

Fastening points
Examples for fastenings points on 8 mm HPL-Compact. For thicker HPL sheets, b and c can be up to 15 % larger; and up to 25 % smaller for thinner sheets. For high wind loads above 1 kN/m2, b and c have to be reduced:

 

Sheet joints for façade panels
Sheet joints have to have 8-10 mm wide gaps to absorb climate-related length changes. Expansions of about 2.5 mm/m are expected. As HPL-Compact can easily be processed with wood tools, sheet joints can also be created with different profiles, e. g. grooves or rabbets. A sufficiently wide expansion joint and sufficiently thick edges must be ensured for these joints. This also applies to the use of profiles, usually made of aluminium, which allow additional options for designing sheet joints. Stored moisture must be avoided in any case.
 

1 “Rain-protected” horizontal joint for timber substructure with PVc or aluminium joint profile. caution: note required space for movement!
2 “Rain-proof” horizontal joint with non-overlapping aluminium joint profile
3 Horizontal sheet end – e. g. underneath window sills – with rain deflection profile on wooden substructure
4 Joint backed with aluminium joint tape, reinforced with a bead