Cladding with Metal and Glass

Properties:
- Lightweight and strong.
- Self-protecting against corrosion.
- Fabricable into precise shapes.
- Accepts various surface finishes.
Production:
- Aluminum oxide extracted from bauxite ore.
- Smelting process removes oxygen to yield pure aluminum.
Alloys:
- Commonly used in construction.
- Alloy series, alloying elements, tempering, and common uses:
  - 3xxx: Manganese, cold working, sheet and plate.
  - 5xxx: Magnesium, cold working, anodized sheet and plate.
  - 6xxx: Silicon and Magnesium, heat treatment, extruded shapes.
Alloy Designation:
- Four-digit number followed by a temper designation.
- Indicates processes used to control strength, hardness, corrosion resistance, and mechanical properties.
- Example: 6063-T6 (Series 6 alloy, heat-treated for strength, corrosion resistance, and weldability, used in extruded shapes).

Heated aluminum is pushed through an extrusion die using a piston and cylinder.
Intricate aluminum sections used for:
- Curtain wall components.
- Door and window frames.
- Handrails and grillwork.
- Structural shapes (wide flanges, channels, angles).
High precision allows for close-tolerance details.
Extrusion Fastening:
- Parallel to the extrusion: Screw ports and shear blocks.
- Perpendicular to the extrusion: Screw slots.
- Snap-together parts for easy assembly.

Aluminum conducts heat rapidly (four times faster than ordinary steel).
$Btu/hr-°F-ft$ (W/m-K)
Aluminum framing systems use thermal breaks to reduce heat flow and improve thermal performance.
Types of Thermal Breaks:
- Pour and Debridge: Rigid polyurethane poured into a channel, then debridged.
- Polyamide Strip: Extruded plastic strips with insulation filler; more thermally efficient.

Anodizing:
- Creates a protective oxide layer.
- Prevents corrosion.
- Can be colored.
- Hard, with excellent resistance to weather and fading.
Organic Coatings (Paints):
- Fluoropolymer Coatings:
  - High-performance finish (PVDF and FEVE plastics).
  - Baked-on in the factory or applied in the field.
  - Longest lasting.
- Powder Coatings:
  - Thermosetting powders applied with electrostatic charge.
  - Low cost, durable.
- Baked Enamel Coatings:
  - Inexpensive, broad color choice.

Three Types:
- Storefront (low-rise).
- Curtain wall (high-rise).
- Window wall (hybrid).
Storefront:
- Least costly.
- Simple extrusion shapes.
- Spans between floors.
- Mostly used at ground floors, modest height limits.
Curtain Wall:
- Hangs off floor edges.
- Complex construction, resists higher wind pressures and water penetration.
- Suitable for buildings of any height.
Window Wall:
- Spans between floors (like storefront).
- Designed for higher wind pressures (like curtain wall).
- Can mimic curtain wall appearance at lower cost.

Stick System:
- Assembled from parts on the building.
- Requires exterior access during assembly.
- Advantages: Low shipping bulk, adjustable to site conditions.
- Disadvantages: Piece-by-piece assembly on-site.
Unit (Unitized) System:
- Assembled into units in the factory.
- Units shipped to the site and lifted into place.
- Installation from the interior.
- Advantages: Minimized on-site labor.
- Disadvantages: Requires more space and protection during shipping.
- Best suited to large buildings with regular configurations.
Assembly Types by System:
- Storefront: Stick-built.
- Curtain wall: Stick-built or unitized.
- Window wall: Mostly prefabricated (unitized).

Designed as drained systems.
Storefront and Window Wall:
- Water drains to the bottom of the framing and is captured by the subsill.
Curtain Wall:
- Water flows toward horizontal mullions.
- Sealed plugs prevent downward draining.
- Weeps in the face allow water to escape.
- Gasket behind pressure plate serves as a water seal and thermal break.
- Water is not drained to the bottom to avoid overwhelming the system.
- Continuous air barrier is important.

Account for differential movements between glass, aluminum framing, and building structure.
Curtain Wall:
- Vertical mullion splices allow movements due to thermal expansion/contraction and building deflection/creep.
- Internal aluminum spline.
Storefront and Window Wall:
- Vertical expansion/contraction is small, no special provisions needed.
- Head receptors allow for vertical movement between structure and framing.

Outside Glazed:
- Glass installed/replaced from scaffolding or staging outside the building.
- Simpler, less expensive shapes.
- Reserved for buildings up to three stories.
Inside Glazed:
- Glass installation from the inside.
- More convenient and economical for tall buildings.
- Requires a more elaborate set of extrusions.
Glazing Types by System:
- Storefront: Outside glazed.
- Curtain wall: Some outside, some inside, some either side.
- Window wall: Some outside, some inside.
Pressure plate and snap-on cover attached after glass installed from the exterior.
Steel or aluminum angle used to hang vertical mullions from building structure edges.
T-anchor at mullion bottom, tightened and cut off after positioning.
Maintains continuity of thermal, moisture, and air barrier control layers.

Two glass cladding systems separated by an airspace.
Reduces heat gains, increases daylighting, provides space for shading elements, permits natural ventilation.

Thin sheets require closely spaced joints to hold sheets flat.
Formed metal panels with deeper profiles are stiffer, installed with exposed fasteners.
Metal plate cladding made from stiffer, thicker panels, with concealed fastening.
Stiffer panels produce flat or curved surfaces with precise, uniform edges.
Example metal plate cladding attachment with:
- Extruded aluminum horizontal furring.
- Extruded aluminum panel clip.
- Metal plate reveal.
- Vertical Z-furring.
- Continuous insulation.
- Thermal break furring clips.
- Air and water-resistive barrier.
- Sheathing.