External Wall Cladding- Wet Sealant Joint
This installation method with sealing joints and tray type (rout and return) panels is one of the most common methods and it is used for a wide range of modern buildings and renovation projects. After fixing Aluminum Composite Panels on the substructure, applying a suitable seal material to the joints is needed to ensure water-tightness. Followings are two standards way of sealant jointing:
- ACPs must be folded to a tray-type panel.
- A continuous V-shaped routed groove is created along the entire panel perimeter at a distance of 25mm from the panel edge.
- After routing, only face skin and minimum thickness 0f 0.51mm of core material should be left.
- The edges are folded after removing the corners in order to create 25mm deep pan or cassette. The panel units are stiffened by riveting the corners with aluminum angels.
- Attach pre punch aluminum clip angles on the center to the returned pan edges at approximately 305mm. The clip angles help transfer the load caused by wind on the panel into the structural supports.
- Clips should be staggered from on panel to another in order to allow sequential installation.
- Rout and Return joints must be minimum 16mm wide to ensure smooth thermal movement.
- Aluminum clip angles must acquire slotted holes at fastener connection points for natural thermal movement.
- The Rout and Return joints are, at last, caulk sealed for better protection against moisture and air.
- Sealant should be hourglass-shaped and the width should be twice depth.
- Backer rod diameter should be 25% larger than the joint to be filled.
- Joint size should be four times larger than the expected amount of movement.
- Ideal joints are within a range of ¼ inches at minimum and ½ inches at maximum.
- Sealant is not caulk and should never be tooled with finger. Thus using the right tool is essential.
- Sublayers needs to be clean and properly prepared.
- For ACPs applying sealants under average temperature conditions is recommended since joints expand and contract with changes in temperature (hot weather causes substrates expand, compressing the joint and cold weather causes substrates to shrink, expanding the joint).
External Wall Cladding- Dry Gasket Joint
This method uses gaskets in joints instead of sealants. The durability of gaskets is comparable to that of the sealant, in addition, this kind joint reduces the amount of dirt or strain on ACM panels surfaces. Followings are steps for gasket installation:
- Before installing, inspect the gasket to ensure that it is free of defects and that it was cut cleanly with no rips or tears.
- Carefully insert the gasket between panels, making sure it is centered between them.
- Never apply release agents or joints compounds on the sealing surface of the gasket.
- For full face gaskets, inserting 2-3 bolts through both panels and gasket will help locate the gasket and keep it from moving while bringing the panels together, reducing damaging or pinching the gasket.
- Lubricate load bearing surfaces with lubricants considering factors such as temperature, particle type and size.
- Lubricants amount can be determined enough when you can see it applied on fasteners from less than five feet.
- Consult the gasket manufacturer for recommended torque values before tightening nuts.
- The best wat to tighten nuts is using legacy method or cross bolt pattern and by using multiple tightening rounds during installation.
- Tighten all nuts by hand but do not exceed 20 percent of the recommended torque.
- Torque each nut to approximately 30 percent of the recommended torque.
- Repeat step 10 by applying 30-40% torque every time until you approach 100% of the full torque.
- Apply at least one final full torque to all nuts in a clockwise position until all nuts are in a uniform torque.
Extra Bond (S-Z)
Extra Bond Horizontal (EBH) is a ventilated type façade based on cassettes mad of Aluminum Composite Panels arranged vertically. The load baring structure consists of an aluminum grid with vertical profiles of large resistance, shaped as letter Ω and L and with horizontal profiles joined with and overlap in the shape of letters S and Z. Cassettes are fixed with screws to vertical load bearing profiles, allowing for thermal expansion of cassettes. The longer horizontal edge of the cassettes is supported with the use of S-Z shaped profiles. The gird is mounted to the wall by L-shaped brackets. Extra bond Vertical (EBV) is same as EBH.
There are a few other methods for ACP installation but they are not as applicable as the methods above. Following are some the methods worth to be mentioned which you can apply to your project if necessary:
- Narrow Open Joint – It is suitable for stone and timber-patterned ACP panels in which narrow joint between the panels are aesthetically effective.
- Roof covering – It is used for roof covering in prestigious projects such as airports, stadiums. In roof cover method, water gutter and water proof sheets ACM panels should be installed so that leaked water can be drained outside.
- Sunshade or Cornice – ACP panels are sometimes used for sunshade or the cornice of building wall.
- Back Panel of Glass Curtain wall – Glass curtain walls sometimes need an opaque spandrel panel for aesthetic and energy-saving purpose. The spandrel back panels must be durable specially to UV waves, because it is hard to replace them after building construction is completed. ALPOLIC ACM panels are most suitable materials for such application
In part 3 of Aluminum Composite Panels Installing and Fabrication, methods of fabrication will be introduced.