types and causes of dampness in a building and its preventions.

1. By Hrishabh
Sharma
Himanshu
Singh
Naved
shakoori
Piyush Pathak

2. THE ACCESS OR PENETRATION
OF MOISTURE CONTENTS INSIDE
A BUILDING THROUGH ITS
WALLS, FLOORS, ROOFS IS
CALLED DAMPNESS.

3. • RAIN PENETRATION.
• DRAIN ABLITY OF SOIL.
• MOST DAMP PROBLEMS ARISE THROUGH THE FAILURE OF
MATERIALS, THE BUILDING’S DETAILING OR INAPPROPRIATE
INTERVENTIONS WHERE WORK HAS BEEN CARRIED OUT WITH THE
WRONG MATERIAL.

4. 1. RISING DAMP
RISING DAMP IS THE RESULT OF WATER RISING THROUGH THE WALLS BY
MEANS OF CAPILLARY ACTION. MOISTURE MAY STEM FROM THE SOIL
AROUND THE OUTSIDE OF WALLS OR FROM MOISTURE RISING THROUGH
THE FLOOR CONSTRUCTION. AS A RESULT OF THE CAPILLARY ‘LIFT’
THROUGH THE FINE PORES IN BRICKWORK AND MASONRY, MOISTURE
REACHES A MAXIMUM HEIGHT UP THE WALL OF ABOUT 1 METRE.

6. 2. BRIDGING OF CAVITY WALLS
IN CAVITY WALLS, WATER WILL PENETRATE IF THE CAVITY IS IMPROPERLY
‘BRIDGED’ BY MORTAR DROPPINGS RESTING ON CAVITY TIES OR BY RUBBLE
DROPPED INTO THE BASE OF THE CAVITY DURING CONSTRUCTION. BOTH ARE
EXAMPLES OF ROUTES FOR EXTERNAL RAINWATER TO FIND A WAY TO SOAK
THE INTERNAL LEAF.

9. 3. HYGROSCOPIC SALTS
AN ADDITIONAL PROBLEM IS THAT THE WATER ABSORBED INTO WALLS
IN THIS WAY CONTAINS DISSOLVED SALTS IN THE FORM OF NITRATES,
SULPHATES AND CHLORIDES. THESE ARE LEFT ON THE WALL SURFACES
AS THE WATER EVAPORATES. THE PROBLEM IS THAT SOME OF THE
SALTS ATTRACT MOISTURE (WHAT IS KNOWN AS HYGROSCOPIC).

11. 4. PENETRATING DAMPNESS
PENETRATING DAMPNESS IS WHERE WATER GAINS ACCESS TO THE BUILDING
THROUGH ITS EXTERNAL FABRIC (WALL OR ROOF) AND IT IS NOT AS SIMPLE AS ITS
NAME FIRST IMPLIES. FOR EXAMPLE, WATER CAN PENETRATE A SOLID WALL DUE
TO A NUMBER OF FACTORS: THE HIGH POROSITY OR DEGRADATION OF THE
BRICKWORK, FOR EXAMPLE, OR FAILURE IN A PROTECTIVE RENDER (PERHAPS DUE
TO CRACKS OR POOR APPLICATION), OR EVEN DUE TO THE ORIENTATION OF THE
WALL (SOUTH WESTERLY ELEVATIONS OFTEN FACE THE FIERCEST MOISTURE-
LADEN WINDS). EACH POSSIBLE CAUSE NEEDS TO BE ASSESSED AND ELIMINATED
BEFORE AN EFFECTIVE REPAIR PROGRAMME CAN BE SPECIFIED.

13. 5. CONDENSATION
CONDENSATION IS A VERY COMMON SOURCE OF DAMPNESS IN BUILDINGS. THE
FACT IS THAT THE AIR AROUND US AND IN OUR HOMES HOLDS MOISTURE (WATER
VAPOUR). THE AMOUNT IT HOLDS INCREASES WITH HIGHER TEMPERATURES AND
WHEN THE TEMPERATURE IS COOLED AND IT HAS MORE WATER VAPOUR THAN IT
CAN BEAR, MOISTURE IS DROPPED ONTO THE SURFACES THAT HAVE COOLED THE
AIR CLOSE TO THEM IN THE FORM OF CONDENSATION.

15. • BY PROVIDING DPC ( DAMP PROOF COURSE ).
• BY SURFACE TREATMENT I.E. BY PROVIDING DAMP PROOF PAINT.
• BY INTEGRAL WATER PROOFING METHOD.
• BY SPECIAL DEVICES I.E. BY PROVIDING CHAJJAS & BY PROVIDING CAVITY
WALLS ETC.