VMZ Flat Lock panels, sometimes known as shingles, are installed on a continuous vented substrate on both renovation projects and new build alike. The system consists of panels with 180 degree hems approximately 25mm wide that interlock and are held on the substrate using cleats. The system allows a great deal of flexibility as flat lock panels can be made to many shapes and sizes. The panels can be square, diamond shaped and rectangular. The maximum recommended visible width for a panel is 600mm with the maximum length being 3000mm. The thickness of the zinc used will depend on panel dimensions with small panels using 0.7mm zinc whereas the larger panels will require 1mm thick zinc. Increased zinc thickness will offer a flatter panel, however increasing panel dimensions will have the opposite effect and may induce some unevenness.
The system is very lightweight as the panels weigh no more than 8 kg/m2 and can be fixed back to both soft wood open gap boarding and plywood. Both substrates require the use of continuous 18mm thick wood and a vented airspace should be left behind the timber of at least 38mm. VMZINC PLUS must be used on plywood substrates. For vertical surfaces VMZINC can be used on vented plywood with VMZ Membrane. When non-combustible substrates are required plywood can be substituted with 0.7mm galvanised steel deck.
The panels are installed in a sequential order from bottom up. The panels are held in place using cleats which can be stainless steel, zinc or galvanised steel. For larger panels galvanised steel cleats are recommended. The cleats should be fixed at a maximum of 330mm centres. For small diamond shaped panels the hems should be slightly notched thus allowing the cleat to sit securely. When installing large rectangular panels the short side should be fixed with a long fixing strip. It is recommended that screws be used to secure the cleats. The use of nails offers significantly less resistance, but in the event of using nails, contractors are advised to use ring shank nails. The panels should be installed with the protective film in place.