Cladding Systems

Manufactured Aluminum and Steel Cladding.

What is Cladding?

Cladding is a vertical building enclosure which supports no load other than its own weight and the environmental forces,

Cladding is not intended to assist in maintaining the structure of a building.

The Purpose of Cladding:

The major purpose of cladding is to separate the indoor environment of a building from the outdoors.

Cladding must prevent the entry of water, e.g. rain, snow and ice into a building.

It must retard the passage of water vapour. causing problems of staining, lost insulating value and corrosion.

The cladding must control the passage of light, especially sunlight. Reducing the effect of glare.

It must resist to the required degree of the conduction of heat into and out of the building.

It should isolate the interior of a building from noise outside, or vice versa.

Resisting Fire - According to the building regulations.

1. Composite Steel panels:

Composite panels have as sandwich construction:

two steel sheets bonded either sides of an insulating core of foam, mineral fiber or similar material.

The bonded panel produces good stiffness.

Panels may be fixed using a variety of techniques including self drilling, self tapping screws and secret fixing brackets located within the panel joints.

1.1 Manufacturing of Steel Cladding:

Coils weighing around 7 tons are loaded onto the line and the liner or inside sheet is fed into the roll forming machines and profiled to a given specification.

Side sealing tape is applied to contain the foam. Both top and bottom sheets are pre heated to between 33 and 35 degree centigrade. And the blended foam is applied via the oscillating foam support.

Both sheets are then brought together whilst the foam is expanding to control the chemical reaction. At the same time polypropylene blocks are used to form the joint detail and panel thickness. It allows for faster onsite construction.

Now, composite strip passes through a curing chamber before being cut to length. It is then inspected, automatically packed and shipped to a holding warehouse before being transported to site.

1.2 Fixing Steel Cladding: Stick cladding systems consist of a

series of vertical members (Malians) and horizontal members (transoms) that form a grid.

This grid is used to restrain solid panels and is normally fixed to the floor edges by especially designed brackets, which provide wind resistance.

The self weight of the curtain wall is normally taken to the ground through the Malians. Malian spacings are normally in the range 1.2 to 2 meters. Although, wider spacings are possible. Transom spacings are normally determined by panel requirements and the architectural treatment of the façade.

1.2 Fixing Steel Cladding: Strong-back cladding systems

have a sub-frame that supports thin cladding panels. Units are normally storey height and 6 – 9 meters wide. They are fixed either to the edge of the floor slab, or to the floor edge beams, or to the columns.

The supporting frame is usually constructed from either hot rod or cold formed steel sections or from stainless steel.

Cladding materials include coated steel and stainless steel; since panels are relatively large it is possible to clad buildings rapidly using storey high units.

2. Aluminum Cladding:

Aluminum framing is used for the vast majority of curtain walling applications, primarily for its excellent strength to weight ratio and its ability to be extrude in complex shapes. At 2.7g/cm2, aluminum is 66% lighter than steel. It is also far less susceptible to brittle fractures.

2.1 Processing:

1. Folding; 2. Routing; 3. Riveting; 4. Mechanical

Fixing; 5. Coating & Spray

Finishing.

2.2 Processing:Folding:

To fold the panel, by machine or manually, cut a V groove on the reverse side using a panel saw with a milling attachment or a hand-milling cutter. The product can then be easily folded. The recommended temperature for folding is over 10ºC.

2.3 Processing:Routing:

The panel can easily be folded by hand if a “V” shaped groove is milled on the rear of the panel.

This can be done using a conventional router. For an accurate and precise by hand folding of the composite panels, giving a good finish, we route the rear side of the panels and extract the aluminum sheet and a part of polyethylene core. Normally 25mm from the edge is grooved and folded. A minimum thickness of 0.3mm of the polyethylene must be left on the bottom / back of the decorative face.

2.4 Processing:Riveting:

Panels can be fastened together or joined to other materials with rivets common to aluminum constructions. For outdoor use and for use in areas of high humidity, aluminum blind rivets with stainless steel mandrils should be used to prevent ugly corrosive edges.

2.5 Processing:Mechanical Fixing:

Can be mechanically secured in place by the use of threaded / screw fixings or rivets. Rivets and screws must be a minimum of 15-20mm from the edge of the panels when fixing. Care should be taken to make sure that the hole diameter allows for expansion and the fixings are not over tightened as this will cause de-formation of the surface.

2.6 Fixing:

2.7 Joints Wind always causes

uneven pressure on a wall. Pressure variations in the plane of the wall can cause lively wind movement behind the cladding as shown in figure 215. Air movement through the cladding can move water into the wall. It is important to seal the air space at the corners of the building as shown in figure 215 c, d and e.

2.7 Joints Much water can

run into the wall if the joints have an inward slant such as figure 217. If the climate isn't too exact one can use horizontal joints with an outward slant.

2.8 Processing:

Coating and Spray Finishing:

The use of air-drying acrylate or two component polyurethane varnishes is necessary. If the panel has been over lacquered it should be bent or folded at a later date.

3 Installation at Site:

4. Comparing between Steel and Aluminum Cladding:

Comparison

Stainless Steel

Aluminum

Weight Heavier Lightweight

Ease of installation

EasyEasier

Cost Average High

4.1 Continued Comparing:

Maintenance Low Low

Colour Silver Large variety

Insulation Good Excellent

flexibility in forming odd

shapes

Very GoodExcellent

corrosion-resistance Low High

5 Conclusion In terms of assembly the cladding

system is very straightforward. The grid is prepared and controlled easily, accepting any alterations required during the job in the local work space assuring the leverage of any heat expansions causing possible movements, and any alteration regarding the fitting and positioning.

The quality of the work could most probably be secured regardless of the constructor's experience, due to the possibility of corrective interventions and adjustments at the site. The work respecting the insertion of the final covering and finishing is extremely tight and completely controlled, thus insuring the cladding acts as a high-quality insulator.

5.1 Conclusion The cladding method is one of many

advantages performing as a high-end solution, each material having of course its disadvantages i.e. Steel has a relatively poor strength to weight ratio, rusts if untreated and turns brittle under stress. Whereas aluminum has a relatively high initial energy cost, however due to the fact that aluminum offers a high manufacturing capability and flexibility, low cost-in-use and also wide ranges of color. It's predictable that aluminum will be more widely used in construction.

Cladding is a very premium process; and is now being turned to for more modernized construction and wide-ranged flexibility in work. Gevahir Mall,

Istanbul, Turkey. 2007

6. Examples of Steel Cladding Worldwide:

London Met. University. London, Uk. By Daniel Rosbottom.

6.1 Examples of Steel Cladding:

The Walt Disney Concert Hall in downtown Los Angeles, California. By Frank Gehry October 23, 2003 and features his trademark steel cladding.

6.2 Examples of Steel Cladding:

Steel cladding façade, Egypt, Zamalek 2007

7 Examples of Aluminum Cladding Worldwide:

Cladding Covered Dome. Millennium Doha, Qatar 2007

7.1 Examples of Aluminum Cladding

Canon building, Amman 2005

7.2 Examples of Aluminum Cladding

Egypt Post, Egypt, Cairo. Modification 2006

8. Interiors:

Airport, sharm el sheikh, Egypt. 2007

8.1 Interiors:

Airport, Sharm el sheikh, Egypt. 2007

9 Exteriors:

Airport, Sharm el sheikh, Egypt. 2007

9.1 Exteriors:

Airport, Sharm el Sheikh, Egypt. 2007