It is necessary to inspect the existing roof terrace and assess the reason for the leakages.
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2.
What is the method of waterproofing a new RCC slab?
To waterproof a new RCC slab, it is best to provide the waterproofing layer directly on the structural slab. The insulation & finishing layers would then come on top. To obtain a sound waterproofing layer use the following procedure:
- Clean the surface of all loose particles, dust, cement laitance etc.
- In case the slab is uneven and undulated it is desirable to make it level and smooth using a thin cement mortar.
- Moisten the RCC slab (or the leveling mortar) with water.
- Apply slurry of Polyalk WP and cement in the ratio of 1: 1.5 (by weight). The slurry should be freshly prepared, uniform in consistency and suitable for brushing.
- After twenty four hours interval apply 2 more coats on the already applied coating.
- Allow it to set for 48 hours.
- Cure the coating with wet squeezed gunny bags.
- Finish the surface as per requirement.
Note: In case the roof is a sloping one, then the 'Polyalk WP'/cement slurry should be applied over the top of the slab.
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3. How is waterproofing of toilets and bathrooms done?
Follow the steps given below for a new construction.
- Clean the surface of the sunken slab of all loose particles, dust, cement laitance etc.
- Moisten the surface with water for half an hour before you are ready to carry out the next step.
- Prepare a slurry consisting of 1 part by weight of Polyalk WP and 1.25 to 1.50 part (by weight) of fresh white or grey ordinary portland cement. Ideally the mixing should be done using a low speed stirrer, but continuous hand-mixing to a lump-free consistency is also adequate. Apply the slurry by brush to the damp surface, taking care to prepare as much slurry as can be utilized within 30 minutes.
- Apply two more brush coats of similar slurry at intervals of 4 hours and allow to set for 48 hours.
- Cure the coating for 7 days by sprinkling water thrice a day on the vertical surface (external walls) and by moist gunny bags on the horizontal surface (terrace). (Please see sketch)
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4. How do you rectify leakages from wet areas like toilets and bathrooms in a building?
In case the leakages are nominal, then grouting at suitable locations with polymer-cement slurry would be likely to solve the problem. Otherwise, the entire bathroom or toilet would require to be renovated.
Remove the existing W.C.Pan, tiles, plumbing etc. from the toilet or bathrooms. Clean the RCC slab of cement laitance, loose material and dust, prepare a cementitious grout modified by 150 ml. Sunpolicrete (NGT) and 2.5 kgs. of Polyalk EP/both per 50 kgs. bag of cement. Restrict the quantity of water to minimum. Infuse this grout preferably under pressure of about 2 kg/cm2.
Prepare a lumpfree consistancy slurry of Polyalk WP and cement in proportion of 1: 1.5 (by weight) and apply this slurry to the area to be waterproofed. Care should be taken that no area remains uncoated. Apply one more coat of similar slurry keeping an interval of 24 hours between two successive coats. After 48 hours cure the coating by sprinkling water for 2-3 days. Provide a leveling course of 1:4 cement- mortar in thickness of 10-15mm if required. Finish the surface as per requirement.
Note:
1. Refix the pan, tiles, plumbing etc. Prepare as much quantity of slurry which can be used within 30-45 minutes.
2. See sketch for details
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5. How does one obtain a long lasting water proof external painting to an existing building?
In order to obtain a long lasting external painting to an existing building :
- Clean the surface thoroughly to remove all loose material, fungus, old paint etc. and moisten with water.
- Mix Polyalk WP in the water used for preparation of the cement paint. Mix thoroughly to a uniform consistency. For the first coat use 20% Polyalk WP by weight of (dry powder) cement paint for the second coat add only 5% Polyalk WP. Follow the usual steps taken in painting the wall using cement paints (powder form)
- Cure the paint after 24 hours.
- Follow the usual steps taken in painting using cement paints (powder form).
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6. How is waterproofing of a chajja (sun shade) carried out ?
- Clean the surface of all loose particles, dust, cement laitance etc. and moisten with water.
- Prepare a lumpfree consistency slurry of Polyalk WP and Cement in a proportion of 1:5 (by weight) and apply this slurry to the surface to be waterproofed, care should be taken that no area remains uncoated. Take 1'-0" above chajja on the wall and around drip mould.
- Apply one more coat of similar slurry keeping an interval of 24 hours between two successive coats.
- After 48 hours cure the coating by sprinkling water for 2-3 days.
- Provide a watta between the brick wall and the RCC Chajjas of larger radius filling the same with brick bat coba to drain the rainwater instantly.
- Provide a leveling course of 1:4 Cement Mortar in thickness of 10-15 mm as required.
Finish as per normal practice.
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7. What is the benefit of using integral waterproofers in concrete?
Integral waterproofer is a polymeric powder which reacts with the alkalinity of concrete/mortar and forms a water-repellant compound throughout the mass of the concrete. Since it does not remain unreacted in the mass of the concrete the strength does not get reduced and the entire capillary structures can get hydrophobic showing significant decrease in permeability.
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8. Which is the best way to repair a leaky water tank?
To repair water tanks, first expose the reinforcement in all damaged areas using steel wire brushes or by mechanical means. There should be at least 6mm gap behind reinforcement to facilitate cleaning, coating etc. Apply a rust removing solution of Rusticide by cotton waste swab or by brush. After 24 hours apply a passivating coat of Polyalk Fixoprime / cement slurry. (No water added to slurry).
Apply two more coats of similar slurry after an interval of 6 to 24 hours between two successive coats.
After interval of 4 hours :
- Apply a priming cum bonding coat of Polyalk EP/Cement slurry in 1:1 proportion (by weight) to damaged concrete surface.(No water added to slurry)
- Immediately place polymer modified mortar by hand mix.
- Replaster the surface by applying bonding of Polyalk EP/Cement slurry in 1:1 proportion (by weight) to the damaged concrete surface.
- Cure the plaster as usual.
- Inject the Polymer Cement Grout of Polyalk EP:Cement water in the proportion of 1:3:2 if required with a pressure of 2 kgs/cm2, seal the grouting nipple with polymer modified mortar.
- Clean the surface thoroughly and moisten with water.
- Apply a waterproofing coat of Polyalk EP:Cement slurry in proportion 1:5 (by weight) with brush to bottom and side of the tank.
- Apply two more coats of similar slurry after an interval of 24 hours between two successive coats.
- After 48 hours cure the coating by sprinkling water for 4-5 days
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9. How do you prevent dampness rising from foundations due to capillary actions from subsoil and destroying the superstructure ?
To prevent dampness rising from foundations due to capillary actions from subsoil and destroying the superstructure:
Drill holes below plinth level for grouting of "Poly Blok" A & B one after the another 15-20 mm dia spaced at 15 cms. Vertically and 20 cms. horizontally ( As shown in figure).
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Tell the mason that adding more water weakens the structure and it creates weak mortar or concrete. Excess water can also lead to draining or oozing out of cement & other fines from gaps and result in honey combs. Instead use of 'Sunpolicrete NGT' a workability improving agent will give them easily workable concrete or mortar.
