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Choosing the Right Façade and Fenestration Products
Ar. Behzad Kharas,
The advent of globalization has helped introduce new window and cladding systems, and cladding materials into the Indian market, which were not available earlier. This advent has introduced multiple choices to the designers and hence a designers need to carefully understand and select the systems that will suit the design best.
The basis of design needs to be broadly done on the following parameters:
1. Climatic context: The choice of material for façade systems in context to local climate
2. Surrounding or micro context: The location of the building in context to its immediate surrounding
3. Design context: The choice of system, material, and color in the context of the intended design
Analyzing these three contexts helps a designer choose the right material for the design being proposed. I’m elaborating on these three contexts to give one a brief idea of what each context means in relation to design.
It is important to analyze the climatic context in which the project is being built. For example, in colder regions, more glazing area happens in the south while in tropical regions and Asian regions it happens more to the north. Many a time we just replicate a design that we like visually as a reference, not realizing whether it would suit that context. I have seen people use big glass panes along the south and east façades resulting in major heat gain into the structure. Even if the design intent has to be such, the choice of glass makes a lot of difference. From low lead content to low E glass helps in reducing the heat transmission through glass. For cladding, I have seen people using normal wood which is not treated in heavy rain zones. Due to heavy rains, the wear and tear of the wood lead to high maintenance. Materials like Shera planks, detached wood, metal composite materials (MCM), Wood-plastic composites (WPC), High-Pressure Laminates (HPL) are alternate choices one has to make in such geographical /climatic conditions.
When it comes to the choice of windows, I have seen many mistakes where a normal window section is put in a high rain or high wind pressure zone causing leakages and rattling of the sections. There are multiple choices one can choose from ALU K has a high-velocity drain section designed frame so that water doesn’t flood the mainframe channel and also has a flap that acts as a non-return valve, further helping to reduce flooding of the window during heavy rain and heavy wind pressure situations.
Many people choose UPVC windows in hot and arid climates not realizing that plastic chips have a reduced life under high UV exposure leading to decolorization and cracking of the section. Many clients opt for the cheapest solutions, not realizing the quality of plastic chips used to extrude the section. Some are cheap solutions that use plastics that are of not a certain grade leading to a lesser life cycle of the window. Essentially this means climate plays a major role in the choice and selection of systems.
The next analysis one does is the context of the surrounding. For example, if the building is near the main road or is the room designed for a high sound level – like a home theatre – making acoustical privacy a concern in design. To reduce traffic noise and noise insulation from inside to outside, and vice versa, one can use triple laminated glass instead of double-glazed systems. It is a common notion that double glaze reduces the noise but that is not so true or efficient. Double glass is meant more to reduce heat gain than acoustical insulation.
The position of the built form becomes a point of consideration if situated in shadow zones due to surrounding trees or structures. Areas that are in a shadow zone or covered by existing trees don’t need Double glazed glass for heat reduction but maybe a window on the east may require a double-glazed system to avoid heat gain into the room. security is also a very important concern while designing window systems. In a high-end residence if the client wishes to avoid grills, which means one has to go for a more secure glass system. high-security risk zones like the windows on the ground floor or roof skylight canopies are where one should opt for sentry laminated glass. If the cost of this is not within one’s budget, then concealing rolling shutters within the façade from the exterior side or within the curtain pelmet from the interiors is a cost-effective option.
Invisible-looking wire or high-tension ropes are more for safety from falling rather than security from outside intrusion. We also now have third-party technology that can be embedded into window systems that detect an intrusion or if a window is left open by mistake and triggers an alarm on the client’s mobile device. The cost-effective alternative is to have glass break-in sensors installed and armed at night to detect any sort of intrusion. Locking systems are also a concern and in general, a multipoint or vertical locking system has a better life cycle and resistance to intrusion than a typical horizontal single locking point system.
The next analysis is the nature of the building. For example, in a residential building, the glazing would have vertical and horizontal fins to give a residential look rather than a simple glazed system where the subframes are hidden behind the glass which makes the built form look commercial in styling. While using glazing systems along a staircase block, especially on the last mid-landing of the home, it becomes difficult at times to access the glazing panels and open them manually. In such cases, one can look at having a motorized glass opening accentuates which motorize the opening of the glazed windows.
These can also be programmed into a mobile device. Choice of material is another analysis one needs to do. Depending upon the design intent of the façade, a designer chooses to clad certain walls in finishes like stone and wood.
Earlier natural stone was the only option designers would look at. From wet cladding of stones, the system graduated to dry cladding. Now from stone, the material choices have graduated to tiles and further on to slim tiles to reduce the weight added to a structure. Besides this, you have products like MCM that replicate the feel of stone and wood at reasonable costs and which are much lighter and easier, and faster to install. Wooden cladding earlier used to be expensive using detached wood. This difficulty was overcome with the advent of WPC or composite wood systems. Then came ACP and HPL which looked like wood but didn’t give the natural feel. Things like wooden cladding from MCM help replicate the same feel at a much cheaper cost.
In choosing windows, most designers today opt for a slim-looking section ensuring better visibility and a more seamless view with better sealing from the exterior climate. Also, most designers opt for taller windows or larger widths of windows. This leads to a higher weight of glass and may lead to difficulty in the opening if the right section and system are not chosen. Such heavy glass sizes and weights require sections with heavy stainless steel bearers which aid in the movement of a window.
The next critical aspect of the design is protection from insects. Mosquito meshes inbuilt into a window system often remain visually obtrusive. Also, these meshes are flimsy and require a horizontal transform mullion to ensure the mesh doesn’t sag. The alternate solution is vertical or horizontal retractable meshes that help to secure the occupants from insects and also have a better visual opening by not seeing the mesh all the time even when windows are closed.
The conclusion is that the choices one has are plenty in the market but making an informed decision based on this analysis of context makes the project better suited for the context and reason it’s built for. Getting carried away by fancy products is a trap most designers fall for not realizing that at a later date the system doesn’t work, support, and solve the intent it was chosen for.
The Cubist Villa for a Maharashtrian joint family is situated in an urban context with an adjoining public garden. The client wanted maximum privacy from the road and massing to build upon the south edge as per Vaastu. The form was derived out of skewed hexagonal boxes stacked one above the other to create visual appeal in the massing. The pergola formations on the northern edge were also created using these hexagonal geometric formations.
A swimming pool in the setback space along the northern edge is screened by a pergola to have visual privacy. Major bedrooms face the public garden to visually borrow the landscape and the theatre, spa was kept on the north façade where the adjoining building is situated.
The souls residing in the villa get connected to nature with the large openings given by the architect, wherein the Cladding, windows, and sliding doors are nicely positioned with a perfect equilibrium maintained for the nomenclature of the panel sizes given. The system used is ALU K SC95 non-thermal break with high-performance glasses specifications as per the functionality and utility of the client, wherein for the hall and dining area the glass used is sentry laminated with soft coated ET135 from Saint-Gobain wherein the security concern was addressed with the glass and with multiple locking system provided in the sliding door.
The other areas like the home theatre are with acoustic laminated for sound resistance and for the gym the focus was to address the heat, so a double glass unit is used. However, to maintain the aesthetic, the shade of the glass is kept the same for the overall villa, and specifications with regards to DGU and sentry and acoustic were used as per the requirement and need. GGS Designers and Fabricators Pvt. Ltd, a well-known aluminium fabricator in north Maharashtra who has executed several villa projects in Nashik and Pan India, which has an excellent set-up in Nashik with all German machinery has nicely fabricated the windows and installed the same.
Materials used for façade & fenestration: ALU K Windows, cladding/ Exterior texture paint by Asian Paints
Commencement date: June 2018
Completion date: June 2020
This project Urban Oasis had a heavy functional requirement in proportion to the plot size. Also, the plot is linear meant that it was difficult for one to visualize the villa from all sides. The main roadside traffic meant that the upper-level living areas had to be pushed back by putting horizontal terraces and projections to create visual privacy. The lower level houses the office of the owner followed by the semi-public areas like the living room, dining kitchen, and guest room. The topmost level houses the family bedrooms and a lounge.
This helps the private areas to get a clear uninterrupted view of the surrounding public garden. The existing trees on site were kept intact to bring in the landscape hence the need for using a reflective glass or high-performance glass was not a necessity. However, considering the aesthetic required and the safety concern, the glass used is brown tinted for the façade with PVB lamination, ensuring safety and to a considerable extent sound and heat resistance.
The fabricator from Nashik, M/S GGs Designers and Fabricators Pvt Ltd has used ALU K System for all the sliding doors and windows with multiple locking. For the dining area and home theatre, lift sliding doors have been used as the opening size is large, wherein each panel weight is around 370 Kgs.
The façade system used as an element feature for the double-height comprises of Aluminium RT of 150 X 50 as vertical members and 200 X 50 as horizontal members within which the fixed glazing is used wherein the Cladding system used has a proper drainage provision.
Materials used for façade & fenestration: Calibrated Granite /MCM wood cladding/ALU K window
Commencement Date & Completion Date: June 2019, under construction
Ar. Behzad Kharas,
Chairman & Managing Director, The BNK Group
Behzad Kharas was a great high-ranking student of architecture winning numerous awards as a student. Graduating in 2002 from Rizvi College of Architecture, he worked with Architects Hafeez Contractor and Pronith Nath. Behzad Kharas started his practice from his hometown Nashik and then later shifted base in 2007 to Mumbai. The journey was never easy with too many failures and struggles, but that never led him to give up. Today he is considered as a peer to many, an influencer in the design industry, and a man with a strong ethos. With his vision and philosophy to be “humane, honest & humble”, he has led the group to where it is at present.