SNP: Water­proof­ing Chal­lenges in High-Rise and Sug­gested Re­me­dial Mea­sures

NBM&CW - - CONTENTS -

If you go around any hous­ing so­ci­ety – high-rise or low-rise - and take a look at the ex­ter­nal walls and pro­jec­tions, I am sure that in more than 90% of the build­ings you will find large patches of water seep­age on the walls. You will find wet patches in the in­te­rior walls of some of the apart­ments as well. And you will also find water drip­ping in many of the build­ing’s base­ments.

Why does this hap­pen? Don’t the builders, de­vel­op­ers, con­trac­tors, and own­ers take care of water­proof­ing? If they do, then what kind of water­proof­ing does the con­trac­tor use? Do they use a pro­fes­sional water-proofer, if at all?

In most of the cases, you will find that these stake­hold­ers do not en­gage a pro­fes­sional water-proofer to un­der­take the most cru­cial part of any con­struc­tion. In most of the projects, while the work for wood­work, me­tal fab­ri­ca­tion, fire­fight­ing, water treat­ment, waste water treat­ment, and elec­tri­cal, is awarded to spe­cial­ized agen­cies, you will be sur­prised that water­proof­ing is kept in the scope of the civil con­trac­tor who does not have enough ex­pe­ri­ence in han­dling this.

The spec­i­fi­ca­tions which are given in 90% of the ten­der doc­u­ments are a cut­copy-paste job based on spec­i­fi­ca­tions that are more than 30 years old, and the rates given in the ten­der for this cru­cial work is some­times less than the la­bor cost, as the con­trac­tors hire work­ers who do not know how to do water­proof­ing. So, all these things - the wrong spec­i­fi­ca­tions, low rates, and un­skilled work­ers, re­sult in a bad job of water­proof­ing and the sub­se­quent fail­ure to pro­tect the build­ing.

To a civil con­trac­tor, a project man­age­ment con­sul­tant and an ar­chi­tect, it could be just a water­proof­ing job. But to a pro­fes­sional water-proofer, it’s a pas­sion to per­form. That’s why, most of the water­proof­ing com­pa­nies have de­vel­oped their own pro­cesses to study, eval­u­ate and de­sign water­proof­ing sys­tems to cre­ate a build­ing pro­tec­tion sys­tem, which not only per­forms and lasts, but also re­duces the en­vi­ron­men­tal im­pact on the prop­erty. The so­lu­tions would be more ex­pen­sive than the ser­vices of a civil con­trac­tor, but the re­sult would be long last­ing, and there­fore, cost-ef­fec­tive in the long term.

Water Proof­ing Is­sues Bath­room Sunken Area:

Gen­er­ally, a water proof ad­mix­ture is used to mix with ce­ment and is brushed on the con­crete sur­face to pro­vide water proof­ing. In such cases, where the water proof­ing fail­ure has al­ready hap­pened, there is no other so­lu­tion ex­cept re­mov­ing the tiles and reach­ing up to the con­crete mother slab. The sur­face should be cleaned prop­erly us­ing a me­chan­i­cal grinder. Among the best prod­ucts to be used for water proof­ing for sunken ar­eas in both pre­ven­tive and re­me­dial treat­ment are PAREX K 11 Flex, Ardex En­dura WPM 004, SIKA Top Seal 107 and other sim­i­lar prod­ucts, which are es­sen­tially Two Com­po­nent Acrylic poly­mer mod­i­fied ce­men­ti­tious coat­ings.

The core cut holes around the pipes should be sealed with Poly­mer mod­i­fied mor­tar or ready to use re­pair mor­tars such as PAREX LANKO 731 or equiv­a­lent.

An­other good prac­tice would be to use Cor­ner Tapes on the wall and floor joints, be­cause these are the most vul­ner­a­ble places for seep­ages.

Roof & Ter­races: Most of the ter­races in a high rise build­ing have as water­proof­ing ap­pli­ca­tion a layer or two of Ce­ment Slurry mod­i­fied with In­te­gral Water Proof­ing com­pounds (con­crete and mor­tar ad­mix­ture in liq­uid form acts both as plas­ti­cizer and water­proof­ing com­pound con­firm­ing to IS 2645). These are cov­ered with Brick Bat Koba and the top layer plas­tered with Ce­ment Mor­tar mixed with In­te­gral Water Proof­ing Com­pound. Now, if a con­sul­tant goes into the spec­i­fi­ca­tions for so-called In­te­gral Water­proof­ing Com­pounds, he would find that these are used “To pro­duce dense struc­tural con­crete for water re­tain­ing struc­tures”. Even though no man­u­fac­turer refers to this as a water­proof­ing sys­tem, still con­sul­tants have been ad­vis­ing use of these for water­proof­ing.

There are many new-age chem­i­cals and poly­mers of all the lead­ing man­u­fac­tur­ers that give bet­ter re­sults and per­for­mance on roof and ter­race slabs. Acrylics, Epox­ies, Polyurethane, Poly Urea from all the man­u­fac­tur­ers have amaz­ing prop­er­ties such as elon­ga­tion, ten­sile strength, tear strength, etc.

For an ex­ist­ing build­ing, where water fail­ure has al­ready hap­pened, once again, the en­tire ap­pli­ca­tion of PCC, BBK or oth­ers should be re­moved to ex­pose the con­crete slab. The sur­face should be cleaned prop­erly and left to dry for a cou­ple of days so that the trapped mois­ture es­capes. The sur­face may have cracks and should be re­paired with Poly­mer Mod­i­fied Mor­tars or Ready-mix re­pair mor­tars such as LANKO 731, SIKA 122 HS or equiv­a­lent. Af­ter the sur­face is pre­pared, you can use Acrylic Coat­ings such as PAREX K10 So­vacryl (Liq­uid ap­plied flex­i­ble acrylic water­proof­ing and seal­ing mem­brane) or Polyurethane coat­ings such as PAREX K 10 Polyurethane Plus (Sin­gle Com­po­nent Liq­uid ap­plied Polyurethane mod­i­fied water­proof­ing and seal­ing mem­brane). The treat­ment should be cov­ered with pro­tec­tive plas­ter.

Base­ment Walls: An­other ma­jor area where water­proof­ing fail­ure is quite ram­pant are base­ment walls. The only and best way to re­pair them is Polyurethane In­jec­tion grout­ing from the neg­a­tive side, which is, from the in­side of the base­ment. Holes on an in­ter­val of 100mm x 100mm should be drilled in the con­crete wall; these should be cleaned, and Zinc Packers should be fixed. While there are many Polyurethane In­jec­tion Grout­ing brands avail­able in the mar­ket, I would put my bet on ConRe­pair CYH 500 or ConRe­pair CY 505 from ConRe­pair Com­pany Ltd., South Korea. Both these prod­ucts are very low vis­cos­ity Hy­dropho­bic polyurethanes that seal and stop water seep­age in­stan­ta­neously.

Base­ment Podi­ums: Podi­ums, gen­er­ally, are used for lay­ing gardens and green ar­eas. Lots of water is reg­u­larly used for the green ar­eas. In case the water­proof­ing has not been done prop­erly, the seep­age starts im­me­di­ately af­ter the gar­den is laid. It has been ob­served in many cases that the water da­m­ages the cars parked in the park­ing below the podium.

Ut­most care is re­quired while do­ing water­proof­ing. The best would be to re­move the gar­den and treat the sur­face from the pos­i­tive side us­ing PAREX K10 GRS 2000SF, a two com­po­nent Polyurethane Root Re­sis­tant Wa­ter­proof Mem­brane for Roof Gar­den & Plater Ar­eas. The prod­uct has high elon­ga­tion of 400% and gives pro­tec­tion against Root Pen­e­tra­tion. How­ever, where it is not pos­si­ble to re­move the gar­den and treat from the pos­i­tive side, it is rec­om­mended to use Polyurethane In­jec­tion grout­ing from the neg­a­tive side - in most of the cases only the af­fected area on a grid of 100mm x 100mm.

In con­clu­sion, I would like to say that all the stake­hold­ers in a project should not ask a water-proofer, “What is the cost of water­proof­ing?” rather, “What is the cost of NOT water­proof­ing?”

For fur­ther de­tails, please contact:

Tel: +91-124-4234567

E-mail: group­snpwa­[email protected]

Web­site: www.conre­pair.in

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