SUBMITTED BY,

THAMANNA JAHAN

ROLL NO: 39

BATCH: S3

BUILDINGS- ROOF, WALL, SLABS, FLOORS

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.

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.

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

PLAN OF BUILDING SHOWING DPC

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.

AIR DRAIN

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.

DPC TREATMENT FOR BASEMENT IN DAMP SOIL

ASPHALT TANKING FOR BASEMENT

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

DPC FOR FLOORING

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.

DPC FOR INTERNAL WALL

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

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.

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)

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

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

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

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.

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

REFERENCE