Architectural Tray
ROOFING & WALL CLADDING
Tray roofing is typically summed up as a secret fix roofing system. The roof sheets are generally held in place by clips fixed to the substrate, with the panels hooked and locked over the clips. This gives a clean & timeless finish to the roof and eliminates the risks associated with numerous screws penetrating products such as long run roofing.
Tray roofing has been in existence for many hundreds of years and has been developed to cope with the harshest of environments. Many European roofs are clad with such products, typically with Lead & Copper in the UK and Raw Zinc in mainland Europe. Aluminums and other metals have been in use for many decades.
Tray roofing has been widely used on high end projects in New Zealand, selected by architects for the aesthetic of simple clean lines and adaptability to suit many roof shapes.
Roofers undergo extensive training and learn the art of traditional sheet metalwork and is a highly regarded skill. It should be considered a craft learnt over years and not a product to be dabbled in.
Solid substrates are typically required to support the flat trays. Our preference is for 17mm ply or greater. Underlays should be breathable and drainage mats are often selected to ensure any condensation to the underside of the tray is allowed to drain or evaporate. Designing adequate roof ventilation requires extra care with Tray products. Refer to NZBC
Using wide flat metal at less than 1mm thick tends to show distortion (known as canning) caused by the thermal expansion and contraction of the flat tray products. This is normal, however the matt finished metals such as Prefa and the raw materials such as VM Zinc tend to show less distortion as they reflect less than the highly reflective painted steel products.
Angle Seam
Double Standing Seam
Batten Cap
Batten Lock
Snaplock
Flatlock
Technical Downloads
Angle Seam
Single Standing Seam
The most flexible roofing product as the widths can be varied to suit any building design, offering sharp lines and with the widest option of metals. Ribs can be lined through with the walls below and varied to suit the positions of roof penetrations and windows below.
Metals used for the manufacture of Angle Seam:
Painted steel (Colorsteel, ColorCote) unpainted and painted Aluminium (Prefa, Alumiguard, Altimate), Raw copper, Raw and painted zinc (VM Zinc).
Double Standing Seam
Double Standing Seam offers most of the benefits and qualities of Angle Seam, however Double Standing Seam involves a double process for closing the seam, which works best with softer, more malleable, raw metals such as Copper and Zinc, as painted finishes can become stretched and microcrack the paint finishes. Prefa Aluminium is designed for Tray and will show the least microcracking of painted metals. New Zealand painted aluminium metals have higher tensile strengths and can show more paint stretching. It is not recommended that painted steel products are used with this design.
There are a number of roof mounting systems for access and services. For example Photovoltaics can be fixed to Double standing seam, or single seam roofs can be double seamed just where the clips are placed.
Metals used for the manufacture of Double Seam:
Unpainted and painted Aluminium (Prefa), Raw copper, Raw and painted zinc (VM Zinc). Some micro-cracking of paint finishes might occur.
Batten Cap/Batten Lock
Batten Cap is the traditional technique used in Europe, where the clip is fixed to the batten. The seam edges can be closed to form a watertight finish.
Batten Lock (batten snaplock) has been developed to omit the batten and replace it with a clip. The cap then snaps over the clip. Careful consideration should be given to detailing junctions such as valleys and roof penetrations. Solid substrates are required for these products
Metals used for the manufacture of Batten Cap/Batten Lock:
Painted steel (Colorsteel, ColorCote) unpainted and painted Aluminium (Prefa, Alumate), Raw copper, Raw and painted zinc (VM Zinc). Subject to detailing, complex details will require a batten Cap and the selection of softer more malleable metals will result in a better finish.
Snaplock
Snaplock products have been developed to reduce the need for solid substrates. They generally have swage on each side of the rib to stiffen the product and give room for heavier duty clips, which are screwed to purlins. Solid substrates are required for Extra High Wind Zones and SEDs. The omission of a solid substrate generally makes the snaplock a more cost effective solution over the total build cost.
Purlins should be fixed at 450mm centres.
Additional swages can be added to the pans to reduce the appearance of canning.
Metals used for the manufacture of Snaplock:
Painted steel (Colorsteel, ColorCote).
Technical Downloads
Coming soon…
