Unitized Glazing System

There is nothing close to a well-designed and correctly executed façade to enhance the looks of a building. From a squat single storied building to the highest of high-rises, if there is one thing which turns heads and makes people head towards a building, it is the latter’s looks which comes in the form of a well-executed façade.

India is undergoing a revolution of sorts on many fronts one of which is to do with construction. Everywhere you look what you get to see are newer and ever taller and larger buildings with the latest amenities and facilities.

One area which is getting increasing prominence with each passing day is that of a building’s façade. With looks taking over centre-stage from yesteryears thoughts of utility, a lot is getting done here though a lot also needs to be done.

Creation and installation of façades continue to be an exercise which is a mix of art, science and correct timing in execution. Even one element missing from this mix and what you get is much lesser than what you could possibly get. With the size and complexity in construction increasing with every passing day, creation and installation of façade too are getting increasingly complex.

Today we tell you all about some of the oft-encountered complexities in the world of façade creation for high-rises and some possible suggestions to overcome them.

Challenges encountered when designing and installing facades for tall buildings

Facades aren’t like a coat of paint which can be peeled and another layer painted in its place. Firstly, for the best effect and to make it long-lasting, facades need to be installed right at the stage of construction which means there ought to be perfect co-ordination between the architect, builder, façade executor, and the latter’s contractor. It is then left to the façade executor to create a plan of installation which is both feasible and timebound under which every element of building construction gets its share of façade basics in place. It also falls on the façade executor to keep the final user of the building in the loop with regard to looks and feel.

Getting all the above elements in place is anything but easy given that it involves different actors and their individual action. Flexibility within a timebound framework is of material importance here.

Difficulties a façade executor goes through with respect to the execution and installation of facades on high-rises.

With each floor being added to a building, the level of complexity as regards façade creation increases exponentially with some of the usual challenges being-

– Kind of material being used

Anything installed at arm’s length is never an issue as regards safety and maintenance. The same can’t be said of installations 300 feet off the ground. The level of planning, material quality as also the systems used to reach such points undergo a quantum change. It’s with experience that one understands the steps needs and the level of quality to be maintained. A façade Contractor’s job thus has to take into account planning projects while being very, very sure of material quality, including the quality of machines used in lifting men and material.

– Quantity of material being used and their storage

Unlike building construction itself where material is used in bulk, in façade installation, it’s every bit about the façade’s design which decides its success. Never-the-less, a façade too calls for its share of raw materials like steel for the installation and glass for the cladding. A proper plan is thus needed to avoid excess stocking or stock-outs which can hinder the speed of project execution besides blocking resources. Excess stocking more so in cramped sites & locations runs the risk of damage to both the installation parts as also the façade itself. It is thus the job of the façade contractor to know exactly what is needed and when, and then plan his next move. There could be a need for multiple vendors for material to avoid stock-outs.

– Material-related logistics and storage above ground

Facades come in all shapes and sizes. Lifts, cranes, gantries, masts, and winches, unfortunately, don’t. The latter sometimes have to be customized to pick and move materials of various shapes and sizes which can be a challenge. Staying clear of hindering construction, they run the risk of increasing project costs as things may have to be customized, sometimes to the extremes.

– Weather-related issues

Facades close to the ground while being installed (and in some cases later also) don’t run the risk of being affected by winds whose effect becomes very pronounced when one continues to rise above the ground. This may have to be tacked in multiple ways including the judicious use of gantries and winches loaded with façade material when functioning against winds of specified speeds. A careful observation of wind patterns needs to be done before execution so as to avoid problems during execution. In some cases, execution may have to be done either at a predetermined time(s) of the day or at predetermined times of the year when wind speeds are conducive to such installation. In doing so, there is always the chance of the project getting delayed and friction developing between the various parties to the project which can be avoided where the builder/ contractor explains these factors to the satisfaction of the party/ client well in time along with the likely implications where caution is not exercised.

– Last-minute changes

When it comes to looks, there is no saying when things and requirements might change. And when they do, irrespective of whether they add anything to the original plan or otherwise, they do add to costs. This is one aspect which needs to be put across to the client by the builder in simple terms. In addition to cost over-runs, last minute alternations/ changes add to time over-runs with the final product sometimes not conforming to the original thought(s).

– Maintenance

It is said that even the Taj Mahal had to undergo a special “mud-pack” to get its resplendent color back, what to talk of facades which resolutely face the weather gods throughout the year! Like everything else, their life too gets shortened with time and the effect of the elements- more so in the Indian context, given our often extreme weather patterns. The challenge here is to maintain them year after year which gets heightened with the dimensions of the building, especially its height. Special equipment and personnel have to be brought in which only add to their cost.

– Scaling up

India wants more. Of everything including buildings. A 15-storey building may need additional floors which means the façade may need to be extended or redone altogether. Depending upon the existing conditions and client’s needs, things may need to be worked out. Scaling up can sometimes be more difficult than new executions especially when a perfect match is asked for. In the absence of the same materials/ designs, the need could extend to a complete re-do.

Experience & efforts have helped bring forth a new technique to reduce façade costs, time and efforts while enhancing their looks and functionality. The “Unitised Structural Glazing system” of which the “Curtain Wall” is its main component, is one where the entire edifice of the façade takes care of its own weight in relation to external factors including wind without in any way affecting the structural unity of an existing structure. The “Curtain Wall” had two variants further, the “stick” system or the “unitized” system. We tell you something about the “unitized” system of curtain walling, its USP and its advantages.

– Unitization of façade!Like the pixels of a digital camera, the façade can be broken down to standard sized panels which makes production, handling, and QC much easier!

– Reduced on-site work !Just 30% of the work to install the façade is done on-site. The rest with respect to producing the façade itself takes place in the factory which means quality is maintained, production losses are reduced and the speed of execution remains high.

– Better quality control! With a majority of the work taking place in automated factories, quality of façade fronts both in terms of looks and material can be maintained – right up to 100%!

– A “Just-in-time” approach is possiblewhere the façade material is brought to the site at the same time that the building comes up. This reduces costs associated with storing material on-site as also losses in storage.

– Lesser dependence on scaffoldings, cranes, winches, and tackles with openings in the new construction being used to install façade- especially useful in high-rises where space can be an issue

– Lesser use of specializedtoolsand tackles which can be replaced with standard tools

– Customization of façade! With installation not being an issue, façade design and ideas can vary from ventilated facades to insulated, sun-protective, automated to even solar-power generation!

– Size of installations no more an issue. With unitization of the façade now being a possibility, the question is not “How to install it” but “Where to install it” with the “where” denoting the place where the building is coming up!

With prefabrication & unitization being the two main USPs of the Curtain Wall, endless possibilities exist to create facades which look good, serve multiple purposes and remain economically priced!

Notes on UNITIZED GLAZING INSTALLATION

• Glazing materials and methods to comply in all respects with the recommendations of the manufacturer of the panel to be glazed for the highest quality installation.
• It is essential that glazing methods allow for expansion and contraction of all components within the system.
• Glazing shall be performed by skilled workmen in accordance with the best trade practices, and without springing or applying force. All instructions from the glass and glazing materials manufacturer shall be followed.
• Tong marks shall be concealed within the stile rebate.
• All adjoining surfaces not to receive glazing materials shall be protected against staining or damage of any kind.
• Glazing rebates shall be clean, dry and free of any materials that might adversely affect the bond and seal of the glazing materials or the proper drainage of the rebate.
• All glass and glazing materials shall be suitably primed unless recommended otherwise in writing by the manufacturer and approved by the Employer.
• All sealants shall match the color of the aluminium framing or glass.
• Setting blocks shall be 90 durometer neoprene rubber of the full width of the rebate and not less than 10mm thick and placed at the glass quarter points. They shall be of a length recommended by the glass manufacturer and be placed in such a way as not to interfere with water drainage of the glazing rebate.
• Jamb blocks shall be used on each glass unit supported on four sides. The blocks shall be 90 durometer neoprene and shall be placed at the top and bottom of the rebate 3mm clear of the glass edge.
• Face spacers shall be 60 durometer neoprene rubber, continuously applied around the perimeter of each glazed opening on both inside and outside faces.
• Exposed sealants shall be installed so that top surfaces of the sealant beads are sloped to drain water away from the glass. All exposed sealant surfaces shall be tooled smooth.
• Sealant tapes or ribbons, where used, shall be mitered at each corner.
• Glass shall be centered in each opening to provide the recess and clearances recommended by the glass manufacturer and approved by the Employer.