Façade Con­sul­tant Har­ish Gupta delves into the pos­si­ble causes of a façade's fail­ure

MGS Architecture - - News - Ar. Har­ish Gupta can be con­tacted for Fa­cade PMC at har­ishgupta@habi­tat-nskins.com

Façade de­signs are be­com­ing more and more in­no­va­tive, and there­fore chal­leng­ing, as ar­chi­tects strive to craft the most strik­ing iden­tity for their build­ing de­sign. But what hap­pens if the fa­cade de­sign and im­ple­men­ta­tion is wrong and it be­gins to fail over time? Façade Con­sul­tant Har­ish Gupta of Habi­tat n Skins delves into the pos­si­ble causes of a façade’s fail­ure and the need for a spe­cial­ist for project man­age­ment

The most strik­ing at­tribute of a mod­ern high-rise build­ing is its ap­pear­ance – the first vis­i­ble con­tact be­ing its façade. But what hap­pens if the façade is not im­ple­mented in a proper man­ner, or it be­comes dull and starts show­ing signs of degra­da­tion over the years? In such a sce­nario, the façade will stop per­form­ing its pri­mary func­tion of pro­tect­ing the build­ing from the out­side en­vi­ron­ment. Slowly, wa­ter and air will start to leak through it. Its el­e­ments will start to fall apart and the façade will be­come dif­fi­cult to main­tain.

Man­ag­ing a Façade Ex­pertly

The cor­rect ap­proach is to have on board an ex­pert project man­age­ment team that is a spe­cial­ist in façade as­sess­ment and im­ple­men­ta­tion, at the de­sign stage. This team will guide the se­lec­tion process and en­sure that the façade is im­ple­mented and man­aged in the cor­rect man­ner. For a very good façade, the façade el­e­ments have to be se­lected care­fully and de­signed with a proper in­ter­face with the main struc­ture. This as­pect is over­looked in nearly 75% of all mod­ern façade build­ings, so much so that the de­sign has to be rec­ti­fied and all in­ter­faces re-as­sessed. Most project man­age­ment teams do not have the req­ui­site ex­per­tise to un­der­stand the nu­ances of the en­gi­neer­ing and ar­chi­tec­tural in­ter­faces of a façade, nor the qual­i­fi­ca­tion. A PMC team, with its ex­per­tise in han­dling façades, will be able to en­sure that all pa­ram­e­ters have been con­sid­ered be­fore im­ple­men­ta­tion of the façade. It can be said with much

ac­cu­racy that al­most 90% of the ex­ist­ing site ex­e­cu­tion teams do not un­der­stand the in­tri­ca­cies of the mod­ern façade and end up mak­ing the im­ple­men­ta­tion in­cor­rect.

No Room for Er­ror

Even a 2 to 5 mm can fail a façade. Sur­pris­ing as it may sound, but that’s the tol­er­ance with which fa­cades are de­signed; while some are de­signed with vir­tu­ally neg­li­gi­ble tol­er­ance. When such a high level of ac­cu­racy is re­quired in de­sign, the same ac­cu­racy is ex­pected in its im­ple­men­ta­tion.

But it needs a dif­fer­ent mind­set to at­tain such ac­cu­racy at site. Most of the en­gi­neers at site han­dle con­crete where tol­er­ance is 25 to 50mm and some­times more is let go. The build­ing is not af­fected by such de­vi­a­tions. The other set of en­gi­neers are for fin­ishes and who deal with ma­te­ri­als that can be rec­ti­fied at site with­out much ef­fort as most are site pro­duced or eas­ily ad­justed. But fa­cades are pro­duced in work­shops or fac­to­ries, and they have to get it right at the first time. Alu­minium and glass are the most abun­dantly used ma­te­ri­als in façades and are cut and pro­cessed to a mil­lime­tre’s ac­cu­racy. If im­ple­men­ta­tion is not as ac­cu­rate, then it will fail. Hence, the role of an ex­pert façade PMC team to en­sure the req­ui­site ac­cu­racy.

Why a Façade PMC Team?

What are the key at­tributes that set a Façade PMC team apart from a reg­u­lar project man­age­ment team? A façade PMC team is es­sen­tially led by de­sign­ers cum en­gi­neers who un­der­stand the de­sign and im­ple­men­ta­tion com­plex­i­ties and can guide the teams func­tion­ing un­der them.

A build­ing façade, if not im­ple­mented cor­rectly, can be a very costly mis­take for fu­ture rec­ti­fi­ca­tion or re­place­ment; even a 2 to 5 mm er­ror can fail a façade

Key fail­ure el­e­ments need to be re­designed in the de­sign stage. Most façade de­sign­ers miss the prac­ti­cal­ity of the de­sign or the im­ple­men­ta­tion method­ol­ogy and end up with in­cor­rect or even im­prac­ti­cal man­u­fac­tur­ing. This leads to on­site ad­just­ments and even­tual fail­ure in the long run. The reg­u­lar PMC team does not have the eye for ac­cu­racy on a day to day ba­sis, un­like a façade PMC team, and therein lies the dif­fer­ence of con­struct­ing a good façade vis-a-vis a failed fa­cade.

Key Fail­ure and Im­prove­ment Zones by Fa­cade PMC

It’s im­per­a­tive that some key fail­ure or im­prove­ment zones are listed out so that costly mis­takes are not made, and clients do not get into rec­ti­fi­ca­tion mode soon af­ter the façade is fin­ished: • Façade de­sign re­view at de­sign stage will iron out de­sign er­rors that could lead to im­proper im­ple­men­ta­tion and also im­proper se­quenc­ing. • De­sign re­view of the façade clean­ing sys­tem is very es­sen­tial at an early stage as many fa­cades are im­prac­ti­cal to clean if the clean­ing sys­tem is not well thought out and in­te­grated in the de­sign. Most build­ings are found dirty and fail due to zero main­te­nance of the joints, which need ex­pert in­spec­tion ev­ery year or two. If a clean­ing sys­tem is ab­sent, then such in­spec­tions can­not be car­ried out. The faults go unchecked, some­times lead­ing to to­tal fail­ure of the façade or even a col­lapse, thereby, en­dan­ger­ing lives. Site in­spec­tion dur­ing construction from fa­cade integration per­spec­tive keeps a check on the ap­pro­pri­ate­ness of a civil struc­ture to re­ceive the façade. This is one of the most ne­glected and over­looked zones in the construction of a su­per struc­ture, and of­ten leads to de­sign ad­just­ment of the façade. Fac­tory checks dur­ing fab­ri­ca­tion and assem­bly of façade en­sure that the pro­duc­tion does not make er­rors, as most prob­lems arise from im­proper fab­ri­ca­tion at the joints, which then need to be site rec­ti­fied. Stack­ing, trans­port and lift­ing of façade is a very chal­leng­ing as­pect. Max­i­mum dam­age to façade hap­pens at these stages, if ill planned. Any dam­age to façade be­yond its tol­er­ance lev­els of ac­cu­racy will surely lead to fail­ure of the façade. Plan­ning ma­te­rial stack­ing near ver­ti­cal lo­gis­tics and ap­pro­pri­ate lo­ca­tion of ver­ti­cal lo­gis­tics with re­spect to place­ment at var­i­ous floors and high winds in a high-rise can make or break a construction sched­ule, if not done prop­erly. In­ter­face of façade with the civil struc­ture is the fi­nal rest­ing place of a façade. Noth­ing can be more im­por­tant than get­ting it right at this point. If ev­ery­thing dis­cussed above is not right, then the fi­nal plac­ing will go wrong and lead to a failed façade. For proper an­chor­ing of façade and seal­ing the gaps and joints, there can be no com­pro­mise in the qual­ity of ma­te­rial and work­man­ship. One needs to un­der­stand the fa­cades are not easy to rec­tify and some­times al­most im­pos­si­ble, as we are deal­ing with fac­tory pro­cessed ma­te­ri­als. Only a Façade PMC team can see the er­rors which are over­looked by a civil, ser­vices and fin­ish­ing based PMC. • Once im­ple­mented, the façade must be checked, cleaned and handed over. The chal­lenge here is to en­sure that other agen­cies are in sync with the sched­ule. If sched­ul­ing and se­quenc­ing is not proper, then the dam­age to the fa­cade by other agen­cies is ir­repara­ble and leads to patch­work.

The reg­u­lar PMC team does not have the eye for ac­cu­racy on a day to day ba­sis as a Façade PMC would have, and therein lies the dif­fer­ence be­tween a good façade and a failed fa­cade

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