METHODOLOGY - WATER PROOFING OF TOILET

Procedures for Waterproofing of Toilets:

Pre Waterproofing Procedures:

1) It shall be ensured that toilet plumbing lines are installed in masonry and chases are rendered with non- shrink grout prior to cleaning activity of sunk is undertaken.
2) Cleaning of sunk slab base and sides of beams shall be carried out as regards all those materials, mortar, oil, grease etc. thoroughly by wire brush and the area shall be washed clean and surface should be wet.
3) Injection grouting at all major honeycombed portions shall be carried out, if necessary, after physical observation of the sunk.
4) Sunk slab shall be cured for at least 2 days by ponding, to test for leakages and to serve water hungry concrete surface.
5) In case of major leakage, gravity grouting or pressure grouting shall be resorted to, to stop leakages.
6) Holes for PVC and other outlet pipes shall be marked clearly for size and locations. Outer surface of PVC pipes shall be roughened for better bonding. Diameter of hole shall not exceed pipe diameter.
7) Levels of water-proofing shall be clearly marked on the toilet walls with slope towards outlet, as specified in drawing or minimum 1:100 otherwise.

During Waterproofing Procedures:

1) Application of chemical waterproofing coat (crystalline / elastometric / polymer) can be done, if required to entire sunk portion before base coat.

2) Base coat using cement mortar in proportion 1:4 or as specified by QA Department with approved water- proofing compound shall be applied over top of base slab of sunk. Maximum thickness of base coat shall be 25 mm at upper end of slope.

3) Proper slope shall be given to base coat as per drawing towards drain spout and drain spout to be fitted simultaneously with the base coat, as an additional precaution to take care of seepage, if any. Base coat shall also be applied to the sides of the toilet sunk up to one foot above the finished floor level (F.F.L) of the adjacent floor.

3) Drain spout shall be 20 mm / 25mm diameter GI / UPVC, fixed so as to project at least 4” beyond wall surface. Drain spout mouth shall be cut to the shape of half nozzle by cutting at 30º angle to facilitate water dropping in the form of a projectile. Holes for drain pipes should be done before starting any type of waterproofing.

4) Drain pipe mouth shall be fitted with PVC grating or filter media form inside and chicken mesh / wire mesh from outside.

5) Curing of base coat shall be done by ponding for 3 days and checked against leakage. Leakage, if observed, shall be rendered with reapplication of base coat to ensure no leakage.

6) Floor traps and other plumbing lines shall be installed in brick masonry after application of base coat.

7) Slope of 1:100 shall be provided for toilet piping and water proofing. Floor trap shall be fixed with respect to finished floor level (F.F.L) of the toilet.

8) Rendering of holes shall be done using compatible bonding agents; SBR based expansive grouts, waterproofing compounds and M15 grade concrete.

9) All internal drain lines shall be erected as per layout given on the drawing and shall be pressure tested.

10) Application of brick bat coba shall be started, once plumbing lines are satisfactory pressure tested.

11) Bricks selected for using as Brick Bat Coba shall be either full brick or 3/4th brick made out of one complete brick by breaking into required size, using mallets.

12) Brick bat shall not be stored in the form of a heap at one place and soaked thoroughly for about 15 minutes prior to their placing.

13) Use of plasticizer in mortars is recommended to increase workability. Mortar mixed shall be used within 1 Hour of preparation.

14) Presoaked brick-bats shall then be laid in straight / radial, by inserting brickbats to a depth of about 15mm by light tamping with the help of mallets. Thickness between adjacent layers of brickbats shall not exceed 25mm.

15) Application of brick-bats shall proceed from one corner and shall be laid in radial pattern / straight pattern to drain of any water which has seeped through. Thiyyas for the same shall be given by Site Engineer, considering into account adequate slope.

16) Edge roundings shall be done simultaneously at corners. (Junction of slab & wall)

17) The brickbat Layer shall then be cured for minimum 3 days by ponding

18) After curing is over, the surface shall be applied with a finishing coat of cement sand mortar in the proportion 1:3 with water-proofing compound till top of brick-bats.

19) Top coat shall be of neat cement slurry of adequate consistency and shall be monolithic with brick-bats.

20) Finished surface shall then be cured for at least 7 days by ponding and then tested for leakages, if any.

Post Waterproofing Procedures:

Date of finishing shall be marked on the surface for curing by ponding for about 7 days.

Important

1) Water-proofing once done, shall not be broken or pierced. If water proofing is to be punctured, due care shall be taken to limit the damage to the restricted area. The cracks due to hammering shall not spread over the large area.

2) Repairing of the punctured area shall be done by using bonding agent and expansive grouts.