Cladtech InternationaI are specialists in the design, manufacture, and installation of aluminium curtain walling, windows and doors for every type of commercial and residential building.

CTI are equipped with a comprehensive range of modern technology in aluminium fabrication.

CTI‘s new factory is designed to take full advantage of modern mass-production techniques to ensure highest levels of accuracy combined with high outputs at optimum cost. All design-work is generated in-house and all installation-works are handled by CTI‘s Contracts Department including all labour and project management on site. This detailed integration of personnel and plant is a guarantee of CTI‘s capacity to deliver even the most complex orders in a timely and efficient manner, and to the standards specified by the Client.

Curtain walling techniques have been used to cover the structural skeletons of high-rise buildings for over a hundred years. Up to around 1960, steel (probably galvanized) was the most commonly used material prior to the arrival of mass-produced aluminium extrusions in the USA. The most famous pioneer of aluminium and glass curtain wall technology was the American Architect, Mies Van Der Rohe, who recognized the colossal advantages of creating a building envelope using these materials. Van Der Rohe described curtain walls as "LESS IS MORE". And today, at CT international we are committed to this philosophy that curtain walling is still the most cost-effective way to clad the exterior of a building structure and to maximise the rented floor space for the developer.

Curtain walling is a grid (sometimes quite massive) of thousands of metal components whose joints are formed mechanically, that-is-to-say they are not welded. This system of mechanical connection is designed to allow for all kinds of differential movement over the life of the curtain wall including thermal expansion and contraction, wind loads, building movements and seismic effects. Nevertheless, the curtain wall‘s main function is to protect the interior of the building from air and water penetration and so we can begin to appreciate the complexity of creating a cladding system which can move and yet maintain a high level of indoor comfort. How is this done?

Curtain wall is designed on the principle of allowing air and water to partially penetrate the system and then to get rid of it by means of pressure-equalised drained joints. Each curtain wall panel or frame-member is designed to interlock with it‘s adjacent components to create a grid of enormous strength when attached to the underlying building structure, while allowing independent movement.
These principles acknowledge the need to provide a building envelope which is, as far as possible, wind-proof, rain-proof but remains light and elegant, thereby enhancing the aesthetic appearance of the building. Frequently, the curtain wall is what we actually see (mainly) when we look at a typical modern structure.

CTI recognize that, in spite of every reasonable effort to prepare the joints in the facade, it is likely that water way penetrate at some location. This may be due to loss of adhesion in the sealants, or through gaskets which have become partially dislodged, possibly during installation, or subsequently. Since there will be (potentially) many linear meters of joints in the surface of a major curtain wall, CTI curtain walls are designed on the "Rain Screen" principle which allows for some random water-penetration through the external seals.

Following from this, CTI curtain wall systems incorporate "pressure equalisation" which is a technique to neutralize any localized build-up of air pressure which might force it‘s way (together with water) through the inner seals and, thus, into the building, Small openings, formed as notches, in the joint-cavities allow water to drain horizontally left and right to be carried down through the mullions and ultimately to the exterior. Thus, the interior seals are not compromised, and the rain screen system is able to perform it‘s function which is to protect the indoor environment.

As expected, the success of the system depends on accuracy of fabrication and installation which depends on the high level of professional attention to detail at CTI.

The design requirement for cutting and machining of extrusions are prepared using Cad/Cam software which is integrated with the factory equipment and directly programmed to carry out all cutting and machining operations. On loading any particular extrusion to the production line, the operation is substantially automated through to completion of the manufacturing sequence.

Drawing Office
Employs specialized computer-assisted drafting and design software for:

•    Curtain wall and window wall systems
•    Glass walls
•    Structural steel
•     Natural stone cladding
•    Precast concrete
•    Roofing
•    Water proofing
•    Metal stud systems
•    GFRC Systems
•    Mock-up drawings
•    Installation Diagrams

Structural Engineering
•    Complete structural analysis and design including windload engineering
•    Evaluation and testing of materials
•    Evaluation of structural integrity of     proposed design solutions
•    Buckling and stability analysis for façade designs
•    Finite element analysis
•    Large deflection and membrane stress analysis
•    Thermal stress analysis
•    Thermal transmission analysis of glazed aluminium façades.

New Systems Design
•    Purpose-made and standard curtain walls
•    Unitized
•    Panelized
•    Stick system
•    Bolted frameless glass facades with glass fins, stainless stell spider-connections, patch-fittings etc
•    Structural silicone glazing
•    Window designs
•    Sliding glass doors
•    Sloped glazing and sky lights
•    Cladding in a wide variety of materials
•    Roofing and water proofing

New Systems Design
•    Structural silicone testing
•    Splice designs
•    Expansion joints
•    Adhesive anchors
•    Mechanical anchors
•    Gasket designs
•    Blast resistance
•    Hurricane resistance
•    On-going development of Co. QA/QC procedures.

Cladtech International design engineers become involved with the project architect and work closely with him from the earliest concept stage of the project and through the many steps required to start the delivery process. We are able to develope practical and cost-effective design solutions which take full account of aesthetic and performance requirements. All of this detailed interaction between us and our Partners/Clients is based on solid design and engineering principles from our in-house resources.

In addition, CTI can produce value engineering experience to ensure that all engineering proposals and solutions are not over-designed and are kept within the project budget, but without compromise to safety and long-term performance. CTI are able to provide this strong advisory role across their entire product range.

Cladtech International has a strong belief in, and an equally strong commitment to the principles of sustainability in all our corporate activities. We thoroughly implement these principles both internally as well as in our total interaction with suppliers and clients at all levels. It is our clear objective to exercise caution at every stage of our processing, administration, manufacture and installation, in order to minimize human impact on the environment.

As specialists in the provision of materials and systems to form the building envelope we are concerned to achieve a deep understanding of the total performance of our work in the terms if energy efficiency, indoor comfort, daylight and views and avoidance of condensation.

These are the fundamentals of good sustainable design for  the 21st  century and we believe that our highly qualified teams have the experience and knowledge  to support sustainable design and product-quality at least equal to the best.

Facade Engineering Services
The building envelope is a key element in the creation of the built environment. The selected cladding system at the heart of the building fabric (Stick, Unitized, or Double Skin) must perform a number of critical tasks without fail, namely:
To – Filter light
To – Moderate heat
To – Block infiltration of air and water
To – Enhance life cycle cost-benefit to the client

CTI provide the following services to the achieve these goals:
–    Research, development and design
–    Engineering
–    Performance testing
–    Thermal analysis
–    Code and authority compliance.

Our main focus is on practical and buildable solutions  which can be efficiently realized by the State-of-the-Art equipment and technology and by our experienced design and production teams.

STRUCTURAL DESIGN

Structural design is an engineering process to determine all the "fail safe" aspects of a structure exposed to the most severe and dynamic forces of nature.

All buildings are subject to movement, and the façade engineer must predict and confirm the effect of complex building motion in relation to the equality complex motion of his materials which all have different coefficients of linear expansion and contraction.

Facade engineering is a specialized link between Civil Engineering and Architecture, and at Cladtech International, we bring this expertise to our industry as specialists at this critical interface, in all our project-work.

The structural design of the façade works at:

–    Wind load deflection calculations.
–    Glass strength and deflection calculations.
–    Fixing methods.
–    Sealant application and gasket design.
–    Ease and efficiency of installation.
–    Method statements.

In addition to the above, the structural design team must assess the overall thermal performance of the façade with regard to system U-values and glass performance.

Cladtech International undertake thermal modeling studies to ensure that their metal works conduct the minimum amount of heat to the structure and the room-interior even under the most severe solar exposure.

Cladtech International also bring their expertise in glass to produce high performance glazing products, in-house, to meet the requirements of the project specification and to minimize direct solar heat gain. In particular, our design team has to ensure the CTI glass has an SHGC (Solar Heat Gain Coefficient) to conform with the calculation by the Project Mechanical Engineer for the capacity of the air-conditioning equipment.

Finally, the structural design team must be aware of all the current Green Building rating systems and municipal building codes which are now in use throughout  the Gulf region. This is of particular importance for projects which require LEED or Estidama Certification which apply to our industry.

"LESS IS MORE"
The principle of attaching a glazed aluminum framework to a concrete or structural steel skeleton was perfectly demonstrated in 1958 by Mies Van Der Rohe and Phillip Johnson in the famous 38-storey Seagram Tower, New York, which is still in perfect condition today.

By means of highly durable bronze anodized extruded aluminum profiles attached to galvanized steel brackets, it was possible to create an elegant fully glazed building envelope which also allowed the owners to maximize the use of the floor space.

"STICK" SYSTEM CURTAINWALL
Essentially, the " Stick Curtainwall System" is constructed on site  using aluminum profiles to create a grid of transoms and mullions all mechanically connected. The majority of the work is ex-factory and the installation starts at the bottom of the façade and proceeds upwards.  Aluminum components are attached to galvanized steel brackets which have been accurately pre-fixed to the structure. Stainless steel screws and bolts are used in order to prevent anodic reaction between steel and aluminum. Stick System Technology is relatively  simple and competitive, although its competitiveness today is somewhat offset by relatively high labour cost and slow pace of installation. All glass has to be installed on site and extreme care must be exercised to ensure that all joints are perfectly  sealed with appropriate materials. In general, it is more difficult to incorporate "rainscreen" principles and pressure equalization into a typical stick system design. Furthermore, this type of curtainwall construction may require external scaffolding and this will, for practical purposes, limit the effective height of the façade. It is not an appropriate technology for "fast track" construction schedules and progress can also be negatively affected by adverse weather.

In terms of aesthetics, the stick system depends on pressure-plates to contain the vision glass and the spandrel panels. The pressure-plates, in mill-finish aluminum, have to be concealed by "snap-on" covers which project beyond the plane of the glazing and are a strong visual characteristic of the system.

A provision of weep-holes and drainage-slots is included to allow water to drain to the exterior.

STRUCTURAL SILICONE CURTAINWALL
In today‘s architecture, the main preference is for "flush glazing" in order to avoid the solid appearance of the standard stick-system grid. Thus, the stick system can be adapted to a modification where the same millions and transoms are bolted to the structure, but the glass and spandrels are factory-assembled into aluminum "carrier frames" which are clipped into place on site. The advantages are:

–    All panels can be flushed-glazed off site using structural silicone sealant.
–    Site work is reduced.
–     Installation programme accelerated.
–    Openable windows and insulated spandrelpanels can be accommodated.
–    Frameless appearance achieved.

TW0 (2) SIDE STRUCTURAL CURTAINWALL
This is a popular curtainwall solution which employs pressure plates and snap-on covers for the transome joints and structural silicone for the mullions, thus providing flush glazing whilst using the horizontal covers as a mainly decorative feature.

Overall, the stick system curtain walling, still has a useful position in contemporary architectural design, particularly for low-rise buildings, and is a mature engineering concept which has evolved over 50 years as a reliable and cost-effective building envelope.

UNITIZED (ON-LINE) CURTAINWALL
The astonishing progress in the design and construction of very high-rise buildings over the past 25 years has called for considerable innovation in the means of making and installing the building envelope. Today, and no doubt in the future, glass and aluminum will feature as the dominant materials of choice to satisfy this "love affair" with glazed facades.

The combination of taller buildings, faster construction schedules and rising labour costs have lead to the development of cladding systems which are substantially built off-site and which are designed to the accelerate installation productivity on site

The unitized system curtain walling is logical response to these demands and brings the benefits of mass-production into play.

Unitization also makes use of advanced labour practices in fabrication and supervision resulting in output of high quality, close tolerances and fast efficient delivery.

For buildings higher than 20 floors, unitized curtainwall panels can be attached by operatives working at the edge of the slab in conjunction with a skilled crane operator.

All seals and gaskets are pre-installed and the connection of one panel to its neighbour provides pressure-equalised self-draining properties according to the "rainscreen" principle to ensure no infiltration of air or water to the interior of a building, and that smoke / fire-stop materials are correctly and accurately positioned.

The system can accommodate open-able windows and spandrel panels with insulated back-pans.

DOORS AND WINDOWS
For virtually every type of building, CTI are able to offer a very broad range of hinged and sliding aluminum doors and windows. The use of robust hardware and well-designed extruded aluminum profiles gives the CTI range of doors and windows a combination of quality, serviceability and durability to perform at maximum efficiency in the most challenging environments. Door and Window glazing is mainly sourced from CTI glass division and includes tempered and laminated safety glass as well as insulated glass units.

BOLTED FRAMELESS GLASS FACADES
CTI are able to undertake full design, fabrication and installation of bolted glazing systems incorporating stainless steel patch-fittings, glass fins, spider connectors and a very large combination of tension-rod designs.

CTI bolted glazing can be single or double glazed with sourcing of structural tempered, tempered-laminated, and tempered-laminated insulated units from CTI‘s glass-processing division.

CTI are also able to undertake are all types of frameless tempered glass for shop-lifting and partitions including a wide range of frameless glass doors with standard or customed-designed metal hardware

HYBRID SYSTEM
Double Skin Façades
The principle of this technology is to provide a glazed façade in which two separate glazed aluminum walls are constructed with a large space between them. The inter-space contains an open-able blind system which can be remotely controlled by a photo electric switch reacting to ambient daylight / sunlight levels. Cooling of the inter-space is done mechanically using low-voltage extractor-fans located above the false ceiling, and, in some designs, return the air back to the bottom edge of the curtainwall via hollow-core concrete floor slabs.

Glazing in this type of system generally comprises a clear, or light reflective, single glazed outer skin and a clear IG unit with a low – E coating on surface # 2 as the inner skin. It is effectively a triple-glazed system in which solar control is achieved by the internal blinds.

There are no open-able windows in the system and all room and inter-space ventilation is done mechanically.
Although coming at a relatively higher cost, double skin façades claim to be cost-effective by providing high levels of daylight and insulation due to their sophisticated control mechanism.

THERMAL MODELING
Depending on various parameters, the solar radiation that strikes any glass surface is partly transmitted, partly absorbed and partly reflected. Basically, the major part that is used to define the thermal behavior of curtain wall is the thermal transmittance of surface or U-value.

Arithmetically, the U-value (the overall heat transfer coefficient) of material defines the rate of heat transfer through an element over a given area and under standardized conditions.

The significant part of the cooling load in a building is due to solar heat gains subject to the area of the façade cover. So the thermal constraint in designing the façade in hot regions is on how to minimize the solar heat gain. On the other extreme end of building envelope design, the heating load of a given space, in cold climate region, is highly influenced by the proposed envelope.

For the above major reason, thermal analysis of curtain wall is carried out analytically. The output of the analysis finally reflects the heat exchange phenomena between the two separated environments and measures the thermal efficiency of the system. As part and parcel of the structural verification CTI carries out the representative thermal analysis for all systems adopted in a project.

Sustainable Facade Design
It is an alarming fact that the UAE has one of the world‘s largest per capita carbon footprints, and is among the top three countries for GHG emissions.

Our cooling dominated environment, ultra-low rainfall and minimal cloud-cover result in an extremely high demand for air-conditioning and water. Over 70%  of the power generated in the UAE is for cooling.

Considering that the main source of heat gain is through the window, it can be seen that thermal efficiency and solar resistance are of paramount importance in the design and construction of modern façades.

In recognition of the urgent need to raise the standard of building design in our Region there is now a growing adherence by developers, government agencies and designers to the principles of the LEED Green Building Rating System. LEED (Leadership in Energy and Environment Design) is a guide to sustainable design and is, at the option of the client, a certification process at various levels of compliance which are:

1. Certified only
2. Silver grade
3. Gold grade
4. Platinum grade

Recently, the government of Abu Dhabi has established the Estidama Pearl Green Building Rating System which has been created with special attention to Gulf Environmental Conditions.

Estidama is a guide to sustainable design and, like LEED, is certifiable according to Pearl Awards at the following levels:

1. Pearl (least stringent)
2. Pearls
3. Pearls
4. Pearls
The government of Abu Dhabi has ordered that all new Government buildings must be designed at least up to 2 Pearl standard.

Both LEED and Estidama are strongly supported by the current American ASHRAE 90.1 Standard.

LEED and Esitidama place a high degree of importance on three critical aspects relating to the design of the building envelope, namely:

1.    Energy and atmosphere.
2.    Daylight and views including indoor air quality.
3.    Regional sourcing and recycling of materials.
5.    Pearls (most stringent)

Together, these three categories can potentially account for over 45% of the points required to achieve a LEED Platinum or a 5-Pearl Estidama sustainable design rating.

Cladtech International is well placed to enable it‘s clients to earn valuable points at every level of Green Building Certification as a result of:

–    Thermally efficient designs.
–    Locally-produced extrusions and gaskets.
–    Locally-produced float glass.
–    Locally-produced solar reflective and low – E glass.
–    In-house glass processing.
–    In-house anodizing and powder coating.
–    Recycling of metal waste.
–    Partial re-cycling of glass waste.

Furthermore, CTI engineers are well-qualified to work with architects and LEED AP‘s (Accredited Professionals) and Estidama AP‘s to assist in the achievement of competent sustainable façades which, potentially, can make a significant contribution of the UAE‘s progress in lowering GHG emissions and shrinking it‘s swollen national carbon footprint.