DETAILED NOTES ON DAMP PROOFING TREATMENT

1. BUILDINGS- ROOF, WALL,
SLABS, FLOORS
SUBMITTED BY,
THAMANNA JAHAN
ROLL NO: 39
BATCH: S3

2. WHAT IS DAMPNESS ???????
 Dampness is a state of diffused moisture in the air, on a surface, or in
a solid.
 Dampness in building or house may cause most of the damage to the
components of the building or house.
RESULTS..
 Dampness often leads to the growth of molds, mites and bacteria that
creates an unhealthy environment and causes health problems.
 Dampness gradually impairs the affected part of the building, so this
problem should be attended as soon as possible. There are many
methods or treatment used to protect the house from dampness.

3. DAMP PROOF COURSE (DPC)
An effective damp proofing material should have the following properties :-
 It should be impervious.
 It should be strong and durable, and should be capable of withstanding
both dead as well as live loads without damage.
 It should be dimensionally stable.
 It should be free from deliquescent salts like sulphates, chlorides and
nitrates.
The materials commonly used to check dampness can be divided into the
following three categories :-
 Flexible Materials: Materials like bitumen felts (which may be hessian
based or fibre/glass fibre based), plastic sheeting (polythene sheets)
etc.
 Semi-rigid Materials: Materials like mastic, asphalt, or combination of
materials or layers.
 Rigid Materials: Materials like first class bricks, stones, slate, cement
concrete etc.

4. DAMP PROOFING TREATMENT
IT CAN BE GROUPED INTO FOLLOWING CATEGORIES:-
1) TREATMENT OF FOUNDATION’S DAMPNESS FROM ADJACENT
GROUND
2) TREATMENT OF BASEMENT
3) TREATMENT OF FLOORS
4) TREATMENT OF WALLS
5) TREATMENT OF FLAT ROOFS, PARAPETS AND CANOPIES
6) TREATMENT OF PITCHED ROOFS

5. PLAN OF BUILDING SHOWING DPC

6. TREATMENT OF FOUNDATION’S DAMPNESS
FROM ADJACENT GROUND
THIS IS DONE BY PROVIDING AIR DRAINS AND DAMP PROOF COURSE OR
DPC ALONE.
SUB SOIL DRAINAGE MAY ALSO BE PROVIDED.
WHAT IS AN AIR DRAIN?
 IT IS A NARROW DRY SPACE ( 20-30 CM)
 IT IS ON THE OUTER FACE OF THE WALL BELOW THE GROUND LEVEL.
 IT IS FORMED BY THIN OUTER WALL RESTING ON THE BASE SLAB OF
FOUNDATION
 LITTLE ABOVE THE GROUND LEVEL(USUALLY 15 CM TO PREVENT
WATER ENTERING THE DRAIN)
 OPENINGS WITH GRATINGS ARE PROVIDED AT REGULAR SPACING FOR
PASSAGE OF AIR.
 TOP OF AIR DRAIN IS COVERED WITH R.C.C SLAB OR STONE SLAB.
 DPC IS DONE HORIZONTALLY AND VERTICALLY.

7. AIR DRAIN

8. TREATMENT OF BASEMENTS
 TO ENSURE THE DRYNESS, THE WHOLE OF THE STRUCTURE BELOW
GROUND LEVEL SHOULD BE PROVIDED WITH A CONTINUOUS
MEMBRANE OF ASPHALT (DPC):- MASTIC ASPHALT OR BITUMINOUS
FELT SUPPORTED ON THE INSIDE.
 IT IS DONE BY SPREADING A LAYER OF DPC OVER THE WHOLE AREA
OF THE FLOOR INCLUDING THE PROJECTION OF 15CM AND
CONTINUING THE SAME THROUGH EXTERNAL WALL.
 DPC FOR BASEMENT MUST BE PROVIDED IN DRY SEASON WHEN SUB
SOLI WATER IS AT ITS LOWEST LEVEL.
 AN ADEQUATE DEWATERING ARRANGEMENT FOR PUMPING OUT
SUBSOIL MUST BE PROVIDED.
 SHUTTERING MUST BE PROVIDED TO PREVENT THE EXCAVATION
FROM COLLAPSING.
 BRICK IS LAID FLAT ON CEMENT CONCRETE TO PROTECT DPC FROM
DAMAGE DURING FLOOR CONSTRUCTION.

9. DPC TREATMENT FOR BASEMENT IN DAMP SOIL

10. ASPHALT TANKING FOR BASEMENT

11. TREATMENT OF FLOORS
 FOR DRY LOCATIONS, A FILLING OF 7.5CM TO 15CM OF DRY COURSE
SAND UNDER THE FLOOR MASONRY IS DONE.
 A HARDCORE FILLING OF STONES WITH SMALLER STONES TO FILL
IN VOIDS IS ALSO QUITE SUITABLE.
 THE FILLING MUST BE WELL RAMMED
 A THIN LAYER OF COAL TAR AND CINDERS UNDER TILED FLOOR ACT
AS GOOD DPC
 WATER PROOFING MEMBRANE OF MASTIC ASPHALT OR FIBROUS
ASPHALT FELT, BEFORE A CONCRETE FLOOR IS LAID.
 GENERALLY, A PRIMING COAT OF HOT LIQUID ASPHALT IS FIRST
GIVEN AND THEN MASTIC ASPHALT IS APPLIED IN 2 COATS.
 CONCRETE FLOOR IS REINFORCED IF THERES IS CHANCE OF
EXCESSIVE UPLIFT PRESSURES DUE TO SOIL AND WATER TABLE

12. DPC FOR FLOORING

13. TREATMENT OF WALLS
 IN CASE OF BASEMENTS:-
 THE EXTERNAL FACE OF WALL IS WELL GROUTED WITH WATER PROOF
CEMENT PLASTER.
 THIS FORMS THE BASE WHICH IS CONTINUED FROM BASEMENT
FLOOR AND
EXTENDED VERTICALLY UP COVERING WHOLE AREA OF EXTERNAL
WALL
FACE.
 A THIN SKIN OF WALL OR PROTECTIVE WALL IS PROVIDED ABOVE DPC
LAYER.
 IN INTERNAL WALLS, :-
 DPC IS PROVIDED IN LEVEL WITH UPPER SURFACE OF CONCRETE
FLOOR.
 CONTINUITY OF DPC BETWEEN INTERNAL AND EXTERNAL WALL IS
ATTAINED
BY WAY OF CEMENT CONCRETE BLOCKS ON BITUMINISED BRICKS.
 IN CASE OF AN EXISTING WALLS:-
 A CUT ABOVE 15CM OR ABOVE THE GROUND IS MADE AT CORNER OF
WALL.
 LOOSE BRICKS ARE REMOVED.

14. DPC FOR INTERNAL WALL

15.  IN CAVITY WALLS:-
 A HORIZONTAL DPC IS LAID 15CM ABOVE
GROUND LEVEL.
 A LAYER OF LEAD SHEET , COPPER SHEET
OR ASPHALT FELT IS BROUGHT DOWN
FROM INNER WALL TO THE HEAD OF FLOOR
OR WINDOW TO PROTECT OPENINGS.
 GENERALLY, A POROUS EXTERNAL
TREATMENT OF PLASTER, HAVING
PROPORTIONS(1 CEMENT : 1 LIME : 6 SAND)
TO THE WALL IS RECOMMENDED

16. TREATMENT OF FLAT ROOFS, PARAPETS AND
COPINGS
 IN CASE OF FLAT ROOFS:-
1) LIME CONCRETE TERRACING
2) LIME CONCRETE TERRACING WITH FLAT TILES
3) MUD PUSHKA TERRACING WITH TILES
 LIME CONCRETE TERRACING:-
 RECOMMENDED FOR HOT AND HUMID REGIONS OF INDIA.
 LAYING LIME CONCRETE AT ADEQUATE SLOPES
 APPLICATION OF HOT PRIME COAT OF BITUMEN OVER DRIED LIME
CONCRETE
 LAYING SHEET OF BITUMEN OVER PRIMED SURFACE
 LIME CONCRETE TERRACING WITH FLAT TILES:-
 RECOMMENDED IN HOT AND HUMID REGIONS
 ROOF IS USED FOR SLEEPING
 ROOF STRENGTHENED BY COVERING LIME CONCRETE WITH 2
COURSES OF BRICK TILES LAID IN CEMENT MORTAR.

17.  THE PROCESS OF LAYING DPC IS DONE IN VARIOUS STEPS:-
a) LAYING DPC OF HOT BITUMEN AT 1.7KG/M.SQ OF ROOF SURFACE.
b) SPREADING OVER HOT BITUMEN
c) A LAYER OF COARSE SAND AT 0.6M.SQ OF SAND PER 100M.SQ OF
ROOF SURFACE
d) LAYING LIME CONCRETE AT PROPER SLOPE IN AVERAGE THICKNESS
OF 10CM
e) LAYING 2 COURSES OF FLAT TILES IN CEMENT MORTAR
f) JOINTS OF TOP TILE IS POINTED USING CEMENT MORTAR(1:3)

18.  MUD PHUSKA TERRACING WITH TILES:-
 RECOMMENDED FOR HOT AND ARID REGIONS
 LAYING DPC OF HOT BITUMEN AT 1.7KG/M.SQ OF ROOF SURFACE.
 SPREADING OVER HOT BITUMEN
 A LAYER OF COARSE SAND AT 0.6M.SQ OF SAND PER 100M.SQ OF
ROOF SURFACE
 LAYING A LAYER OF MUD PHUSKA PREPARED FROM PUDDLED OR CLAY
LIME CONCRETE
 COVERING THE MUD PHUSKA LAYER WITH MUD-GOBAR MORTAR(3 MUD
: 1 COWDUNG)
 FLAT TILES ARE LAID WITH CEMENT MORTAR (1 :3)
 JOINTS GROUTED

19. POINTS TO BE NOTED FOR WATER PROOFING
OF ROOFS
1) SHUTTERING SHOULD BE EITHER OF STEEL OR STRONG WOOD
2) JOINTS MADE WATER TIGHT
3) RCC SLABS MADE DENSE WITH VIBRATORS
4) TOP SURFACE OF RCC SLAB FINISHED WITH CEMENT MORTAR(1:3)
5) SURFACE OF SEALS IS CLEANED WITH RAG SOAKED IN KEROSENE
OIL AND TREATED WITH 2 COATS OF HOT BITUMEN.
6) BITUMEN PADS SHOULD BE USED BETWEEN SLABS AND JUNCTIONS
OF SLABS.
7) FINISHED SURFACE OF ROOF SHOULD HAVE A SLOPE OF 1 IN 50

20.  IN CASE OF PARAPETS AND CANOPINGS:-
 DPC (ASPHALT) COVERING ROOF EXTENDED UP THE JUNCTION
AGAINST PARAPET WALL ATLEAST UPTO 15CM HEIGHT
 DPC LAID IN FULL THICKNESS OF WALL INCLUDING ANY PLASTER
 DPC UNDER COPINGS ARE PROVIDED WHERE BRICKS USED ARE
POOR QUALITY
 A METAL FLASHING ON EXTERIOR SURFACE OF PARAPET WALL CAN
BE PROVIDED TO ATTAIN CONTINUITY IN DPC

21. TREATMENT OF PITCHED
ROOFS
 DESIGN AND CONSTRUCTION OF
ROOF TILES AND ROOFINGS SHEETS
MUST BE TAKEN CARE.
 ROOF SLOPES MUST BE SUFFICIENT
FOR A PARTICULAR BUILDING
 RAIN WATTER GUTTERS MUST BE OF
SUFFICIENT CAPACITY, WATER TIGHT
AND CAPABLE OF ACCOMODATING
VARIATIONS DUE TO TEMPERATURE
CHANGES WITHOUT LEAKAGES.
 TILES SHOULD BE PROJECTED
BEYOND EDGE OF GUTTER
 LEAD FLASHING(DPC) PROVIDED IN
GUTTER SHOULD BE EXTENDED UP
SURFACE OF PARAPET WALL AND
PARTLY INSIDE BODY OF WALL.
 PARAPET WALL MUST BE
PROTECTED BY COPINGS OF STONE
OR WELL BURNT BRICKS WITH DPC
UNDERNEATH.

22. REFERENCE
 WEBSITE:-
 http://constructionduniya.blogspot.in/2012/06/materials-used-for-damp-proofing.
html
 http://theconstructor.org/building/protection-of-buildings-against-dampness/
4577/
 http://www.gharexpert.com/articles/Dampness-2016/Damp-Proofing_0.aspx
 http://theconstructor.org/building/damp-proof-course-dpc/4590/
 BOOK:-
 BUILDING AND CONSTRUCTION-S.P.ARORA AND S.P.BINDRA