Techny Chemy : Water­proof­ing Meth­ods

NBM&CW - - CONTENTS - Er R. Mad­husu­dan Raj, Man­ager Projects, Techny Chemy

Water­proof­ing is the process of mak­ing a struc­ture wa­ter­proof or water re­sis­tant so that it stays un­af­fected to the exposure of water, wet en­vi­ron­ment and other sim­i­lar con­di­tions. There is a wide dif­fer­ence be­tween wa­ter­proof and damp proof. Water proof is the re­sis­tance to the pen­e­tra­tion of water in liq­uid state whereas damp proof is the re­sis­tance to mois­ture, hu­mid­ity or damp­ness.

One of the main re­quire­ments of a build­ing is that it should be dry. Water proof­ing can be de­fined in a very sim­ple way. "It’s a process which does not al­lows ex­ter­nal water to pen­e­trate dry ar­eas of a build­ing and water to move out of wet ar­eas of the build­ing.” Water leak­age not only af­fects the life of the build­ing but also cre­ates un­hy­gienic con­di­tions in­side the build­ing.

Im­pli­ca­tions of Water Leak­age

• Peel­ing of plas­ter or paints and for­ma­tion of ef­flo­res­cence

• Cor­ro­sion of re­in­force­ment which leads to spalling of con­crete

• De­cay caused may lead to warp­ing, buck­ling and rot­ting of tim­ber in the build­ing

• De­te­ri­o­ra­tion of elec­tri­cal fit­tings

• Growth of ter­mites

Sources of Seep­age

• Cap­il­lary pores/dif­fer­en­tial shrink­age

• Con­struc­tion joints/hon­ey­combs

• Fail­ure of water bars

• Ex­pan­sion joints

• Form & Tie Rod holes

• In­ad­e­quate drainage

• Rise in water ta­ble

Cap­il­lar­ies / Dif­fer­en­tial Shrink­age

Cause:

• Time lag be­tween mix­ing and pour­ing, work stop­pages

• Ex­treme cli­matic con­di­tions – mi­cro­c­racks So­lu­tions:

• Con­tin­u­ous cap­il­lar­ies are dis­rupted by chem­i­cal ad­mix­ture – TEC MIX 150

• Sur­face ap­plied coat­ings to bridge hair­line cracks - TEC WAVE 2000

Con­struc­tion Joints / Hon­ey­combs

Cause:

• Ex­ces­sive water

• Poor shut­ter­ing

• Con­struc­tion prac­tice – walls / col­umns cast in lifts

So­lu­tion:

• Poly­mer mor­tar for V groove

• In­jec­tion grout­ing

• Al­lows 45 – 60 min­utes for plac­ing con­crete

Tech­niques and Re­quire­ments of Water Proof­ing

There is a mis­con­cep­tion that water proof­ing can be done with a sin­gle prod­uct. Fail­ure in water proof­ing jobs is caused be­cause of this mis­con­cep­tion. Water­proof­ing is a sys­tem that has var­i­ous re­quire­ments.

Study the Prob­lem

• In­spect the in­side of the struc­ture and pin­point the ex­act lo­ca­tion of in­te­rior leak­age

• Study the orig­i­nal plans and spec­i­fi­ca­tions

• De­ter­mine what type of water­proof­ing sys­tem was used in the orig­i­nal con­struc­tion

• Ex­ca­va­tion and in­spec­tion must be done in or­der to re­li­ably un­der­stand the na­ture of the prob­lem

Re­quire­ments of Water Proof­ing Treat­ment

• Im­per­me­abil­ity to pre­vent pas­sage of water

• Min­i­mize water ab­sorp­tion by sub­strate

• Good bond­ing with sub­strate

• Elas­tic­ity to re­sist crack­ing

• Easy to ap­ply

• Com­pat­i­bil­ity with sub­strate

• Re­sis­tance to UV at­tack

• Re­sis­tance to ser­vice tem­per­a­ture dif­fer­en­tials

• Re­sis­tance to water

• Long life and dura­bil­ity

• Econ­omy

Tech­niques of Water Proof­ing

• Gu­nit­ing

• Grout­ing

• Bi­tu­mi­nous sys­tem

• In­te­gral water proofers

• Sil­i­cone coat­ings

• Water based coat­ings

• Poly­mer mod­i­fied ce­men­ti­tious coat­ings

• Epoxy coat­ings and mod­i­fied epoxy coat­ings

• Polyurethane coat­ings

• Poly­mer based spray ap­plied mem­brane

• Polyurea

Ar­eas of Ap­pli­ca­tion of Water Proof­ing

Pos­i­tive Side Water Proof­ing:

• Pos­i­tive side is same side of the struc­ture as the source of the water

• De­signed to stop water be­fore it has a chance to en­ter the struc­ture and cause struc­tural dam­age

• Typ­i­cally, the most ef­fec­tive so­lu­tion

Neg­a­tive Side Water Proof­ing:

• Neg­a­tive side is op­po­site the water pres­sure side of the struc­ture

Water­proof­ing So­lu­tions

Sur­face Prepa­ra­tion: For a suc­cess­ful water proof­ing job ex­e­cu­tion, prepa­ra­tion of the sur­face plays a vi­tal role.

• Sur­face must be struc­turally sound

• Treat cracks and move­ment joints

• Clean and free from any con­tam­i­nant ma­te­ri­als

• Re­pair any holes/voids in the sub­strate

• Re­move any pro­tru­sions and sharp edges

• Con­crete should be aged for 28 days and screeds should be aged for 7 days

• Ce­men­ti­tious sur­faces can de­velop plas­tic shrink­age cracks dur­ing ini­tial cur­ing, which must be to­tally formed be­fore the mem­brane is ap­plied.

• En­sure sub­strate is dry (5% mois­ture or less)

• High sub­strate mois­ture con­tent will form blis­ters in the mem­brane dur­ing cur­ing.

Range of Prod­ucts

Build­ing friendly and user-friendly coat­ing sys­tems that are tai­lor­made for spe­cific ar­eas of ap­pli­ca­tion.

• Water­proof­ing mem­brane coat­ing

• High flex­i­bil­ity mem­brane

• Crys­tal­liza­tion type coat­ing

• Sol­vent-free food grade epoxy coat­ings

• Water thinnable epoxy coat­ing

• Mod­i­fied bi­tu­men based coat­ing

Spec­i­fi­ca­tions for Water Proof­ing Sunken Por­tions:

In a build­ing the main prob­lem­atic area is the sunken por­tions. Spec­i­fi­ca­tions for solv­ing leak­age prob­lem aris­ing in sunken por­tions are given below.

• Water should be stag­nated in the sunken por­tion for a min­i­mum pe­riod of 72 hours to iden­tify seep­age points.

• Pock­ets should be drilled at these points, weak con­crete junc­tions and hon­ey­combs and PVC noz­zles fixed us­ing in­stant plug- TECR STOP. • Dress­ing the con­crete joints and hon­ey­combs and patch­ing with mod­i­fied ce­ment mor­tar pre­pared us­ing TECR BOND SBR.

• Neat ce­ment slurry ad­mixed with TECR SWELL (@225 gms per bag of ce­ment) shall be grouted un­der pres­sure through the nip­ples pro­vided us­ing a hand op­er­ated grout­ing pump.

• The floor and wall sur­face should be cleaned and be free of dust and loose par­ti­cles.

• Over the walls and floor two coats of TECR WAVE 2000- flex­i­ble mem­brane water­proof­ing coat­ing is to be ap­plied strictly fol­low­ing mix and ap­pli­ca­tion in­struc­tions for the prod­uct.

• The con­crete sur­face should be wet­ted but free of water pud­dles prior to ap­pli­ca­tion of TECR WAVE 2000.

• While the sec­ond coat of TECR WAVE 2000 is still tacky, ce­ment plas­ter­ing in CM 1:4 ad­mixed with TECR MIX 100 liq­uid (@250ml per bag of ce­ment) should be car­ried out and fin­ished neatly.

• Pipe and trap joints should be sealed with an ap­pro­pri­ate seal­ing sys­tem de­pend­ing on site con­di­tions.

• The treated area should be cured ad­e­quately for a min­i­mum pe­riod of 7 days.

It is al­ways bet­ter to pre­vent than cure. Many peo­ple are ready to spend lakhs on in­te­ri­ors but ne­glect spend­ing a few thou­sands on water­proof­ing. It is bet­ter to un­der­take water proof­ing to pre­vent prob­lems in fu­ture.

For fur­ther de­tails, please contact:

Tel: +91 - 431 - 2458519

E-mail: [email protected]­ny­chemy.co.in

[email protected]­ny­chemy.co.in

Fail­ure of Water BarsCause:• Thrust dur­ing pour­ing• Dis­place­ment dur­ing ap­pli­ca­tion of nee­dle vi­bra­tor• Leak­ageSo­lu­tion:• Epoxy bond­ing agent (TEC BOND EPO) -Struc­tural bond­ing of old con­crete with new 2 – com­po­nent sys­tem – easy to ap­ply

Newspapers in English

Newspapers from India

© PressReader. All rights reserved.