Ferro-ce­ment is set to make a come­back given its struc­tural strength, re­silience, eco-friend­li­ness, and cost-ef­fec­tive­ness: Ar. Babika Goel

Ferro-ce­ment, a much tried and tested con­struc­tion ma­te­rial, is set to make a come­back given its many aʃributes of struc­tural strength, re­silience, eco-friend­li­ness, and cost-ef­fec­tive­ness, writes

MGS Architecture - - Front Page - Ar. Babika Goel

Re­in­forced ce­ment con­crete (RCC) struc­tures give the skele­tal frame­work for con­crete beams and col­umns, and the gaps are then filled in with bricks to make the walls. Brick is a prac­ti­cal and pop­u­lar con­struc­tion ma­te­rial; how­ever, it comes at a cost to the coun­try’s re­sources. Agri­cul­tural land in In­dia is slowly be­ing sac­ri­ficed to make quick money through the much in de­mand brick kilns. The clay for bricks comes from this land, de­plet­ing its top soil, and to achieve good qual­ity bricks th­ese kilns also use coal, a fast-de­plet­ing nat­u­ral re­source.

So why are we not us­ing tra­di­tional build­ing ma­te­ri­als such as ferro-ce­ment that have proved their worth over time? Ferro-ce­ment pro­vides bet­ter crack­ing re­sis­tance, higher ten­sile strength to-weight ra­tio, duc­til­ity and re­sis­tance to im­pact, fire, earth­quake, and cor­ro­sion as com­pared to wood, re­in­forced con­crete and ma­sonry.

The raw ma­te­rial that goes into ferro-ce­ment is wire mesh, small di­am­e­ter iron wires for the skele­ton, and sand and ce­ment for bind­ing. It is a bet­ter al­ter­na­tive to brick be­cause it not only re­duces cost by re­duc­ing the over­all RCC con­sumed in the struc­ture, but also makes the struc­ture earth­quake re­silient, ter­mite-proof, and even mono­lithic, if de­sired.

For ther­mal in­su­la­tion, two lay­ers of wire mesh and iron wires are erected and a ther­mo­col layer is in­serted in-be­tween the skele­ton. Mor­tar is then forced on both sides, ei­ther by hand, like plas­ter­ing, or by grunt­ing, if time is a con­straint. The sur­faces are then smoothened and painted. The thick­ness achieved will be much less than fin­ished brick ma­sonry, even with a ther­mal cav­ity.

What’s more, ferro-ce­ment does not re­quire ex­pen­sive man­u­fac­tur­ing plants, and the skills re­quired are only an ex­ten­sion of the tra­di­tional skills that our ma­sons are much used to. Given that we have a very large work­force with lim­ited em­ploy­ment av­enues for them, work­ing with ferro-ce­ment will open up more job op­por­tu­ni­ties.

Case Study

Ferro-ce­ment, as the name sug­gests, is ce­ment and steel mixed and ap­plied in a spe­cial way. Un­skilled labour can be eas­ily trained to use it. It al­lows ar­chi­tects to ex­per­i­ment with curves and un­usual sur­faces, and has the mag­i­cal abil­ity to take any de­sired shape. Many trop­i­cal coun­tries are us­ing ferro-ce­ment to build homes and other struc­tures.

One such ex­am­ple is the Boomerang House in Ti­la­ran, Costa Rica. This small 1000 sq.ft. struc­ture

takes in­spi­ra­tion from the Aus­tralian boomerang. Built to a struc­tural re­sis­tance of 8.0 on the Richter scale, its aes­thet­i­cally ap­peal­ing with warm, yel­low light ra­di­at­ing from its curved, glass en­trance, with a grass-cov­ered roof and walls, lend­ing a look of raw mod­ernism to the struc­ture. The house is the sus­tain­able cre­ation of in­no­va­tive de­signer Jean Paul Cazedessus

Case Study

Kut­tanad in Ala­paz­zhua, Ker­ala, lies be­low sea level; here, build­ing a house is a Her­culean task be­cause the land is highly wa­ter­logged. Though at­trac­tive for tourists with its paddy fields and en­chant­ing back­wa­ters, for most in­hab­i­tants, the only liveli­hood is agri­cul­ture and fish­ery. A pucca house on the clayey soil would be ex­pen­sive for them as it would re­quire a pile foun­da­tion and RCC as the con­ven­tional method for con­struc­tion,

To pro­vide an al­ter­na­tive, P. J. Vargh­ese, Ar­chi­tec­tural and Ferro-ce­ment Con­sul­tant from

In In­dia, there is an acute short­age of ‘pucca’ houses for the poor, houses that are solid, with ba­sic ameni­ties and ar­eas for bathing, cooking and sleep­ing. Gu­jarat and Ut­trak­hand which wit­nessed con­sid­er­able dev­as­ta­tion due to earth­quakes, land­slides, flash floods, and for­est fires, had re­sorted to tem­po­rary shel­ters built with fer­ro­ce­ment walls. Fer­rotech­nolo­gies Pvt. Ltd. in Changanacherry, Ker­ala, along with his team of Civil Con­sul­tant Biji John and Struc­tural Con­sul­tant Prof. G. Hari, used fer­ro­ce­ment tech­nol­ogy to build a house. It low­ered the cost dras­ti­cally and pro­vided more footage for the struc­ture. Had the owner gone by the con­ven­tional method of con­struc­tion, the to­tal plinth area would have been 2,148 sqft, but fer­rotech­nol­ogy saved him 358 sq.ft. of space, keep­ing the same room area. The added ad­van­tage is curved walls built with­out any ad­di­tional ex­pense and the en­hanced aes­thetic ap­peal.

Ac­cord­ing to the rec­om­men­da­tions of the Struc­tural Engi­neer based on the soil test re­port, pil­ing was es­sen­tial for the site for which the es­ti­mated cost was `8.75 lakh. How­ever, with ferro-ce­ment, pil­ing was not re­quired. An in­verted T- beam re­sisted sink­ing and set­tling was pro­vided, which alone trans­ferred the load of the struc­ture safely to the sub­soil. Cost of the foun­da­tion also stood re­duced as the to­tal weight of the ferro-ce­ment struc­ture was less com­pared to a con­ven­tional struc­ture. The con­struc­tion started from the ground level only af­ter sta­bi­liz­ing soil by com­paction.

Says Biji John, “Nor­mally, build­ings here are con­structed only with pile foun­da­tions, which in­creases the con­struc­tion cost. Ferro-ce­ment tech­nol­ogy is the most ap­pro­pri­ate con­struc­tion prac­tice in the area. In this project, pil­ing re­placed by in­verted T Beam, pro­vides more footage for the build­ing, which in turn re­sists sink­ing and set­tling. In this project no deep foun­da­tions are used, yet the struc­ture is very sta­ble and free of cracks even af­ter one year of com­ple­tion. Proud of the tech­nol­ogy.”

Case Study

Jairam Lal, a struc­tural engi­neer in Ker­ala, builds fer­ro­ce­ment struc­tures in two ways: pre­cast or in situ. In the pre­cast method, he found that plas­ter­ing the walls to the re­quired thick­ness and han­dling the pan­els added to the con­struc­tion cost. The pre­cast panel sur­face is too smooth to ap­ply the plas­ter on, so the op­tion for stucco plas­ter­ing would dra­mat­i­cally in­crease the labour cost. So, in his view, it’s al­ways bet­ter to do ferro-ce­ment work in the con­ven­tional way.

In his cur­rent work go­ing on in Kol­lam in Ker­ala, he is us­ing both the meth­ods. This 1,770 sqft house would have gone up by ap­prox­i­mately 300 sqft if brick con­struc­tion had been used due to in­creased thick­ness of the walls. The house does not have RCC col­umns or beams but a rec­tan­gu­lar hol­low steel sec­tion wrapped in brick ma­sonry, which adds to the aes­thet­ics.

Says Jairam Lal, “I fell in love with this won­der­ful tech­nol­ogy while study­ing Civil Engi­neer­ing. Since then, I started read­ing about this ma­te­rial and I re­al­ized how ef­fec­tively I can use it for low cost hous­ing. Next to water, steel is the most abun­dant ma­te­rial on earth, which can be re­cy­cled and used again. Ce­ment too is made mostly out of fly ash (a waste prod­uct from coal power plants). An­other great ad­van­tage of ferro-ce­ment is that it ex­erts only ¼ weight as com­pared to a nor­mal brick wall, so we can save a lot in the foun­da­tion work, plus it con­sumes only 6-8% of the wall area. It is also highly earth­quak­ere­sis­tant be­cause of the closely spaced re­in­force­ment.”

Ferro-ce­ment struc­tures need skilled labour to ap­ply the mor­tar over the mesh re­in­force­ment. On a sin­gle go, it should give a cover of 40-50 mm, then one can fin­ish the sec­ond coat of plas­ter with 15mm thick­ness on both sides of the wall, if one is look­ing for con­cealed wiring and plumb­ing, hence, on the fin­ish­ing stage, the to­tal wall thick­ness will be around 80 mm. Ut­most care should be taken in cur­ing be­cause if fer­ro­ce­ment is not prop­erly cured it will have hair­line cracks. Mostly, the cracks ap­pear over the door and win­dow frames be­cause of the shrink­age of wood, hence, while plas­ter­ing, one can ap­ply a small piece of glass fi­bre mesh on the cor­ners to pre­vent the cracks from run­ning.

In the early 1970’s, labour-in­ten­sive ferro-ce­ment con­struc­tion was viewed as par­tic­u­larly suit­able for ru­ral ap­pli­ca­tions in de­vel­op­ing and trop­i­cal coun­tries. In ur­ban en­vi­ron­ments like Sin­ga­pore and other de­vel­oped coun­tries, the ap­pli­ca­tion of ferro-ce­ment was viewed from a dif­fer­ent per­spec­tive due to the com­pet­i­tive­ness in the con­struc­tion in­dus­try, and the in­crease in labour cost cou­pled with short­age of skilled con­struc­tion work­ers. To al­le­vi­ate th­ese prob­lems, mech­a­nized pro­duc­tion and proper choice of re­in­force­ments are be­ing pur­sued to en­sure cost com­pet­i­tive­ness and speedy con­struc­tion. In In­dia, all we need now is to kick­start us­age of ferro-ce­ment by the ar­chi­tects.

Res­i­dence of Mr. Chachap­pan A G in Kavalam, Alap­puzha, Ker­ala. To­tal area - 1,790 sqft; foun­da­tion and base­ment - RCC in­verted T beam; walls, para­pet walls and weather shade – ferro-ce­ment; roof slabs – fer­ro­crete

Ferro-ce­ment work by Jairam Lal go­ing on in Kol­lam in Ker­ala us­ing both pre­cast and con­ven­tional meth­ods. This 1770 sqft home in ferro ce­ment can go up to 2100 sq.ft. in nor­mal brick con­struc­tion be­cause of the wall thick­ness. The to­tal es­ti­mated cost is `28 lakhs.

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