This document provides an overview of moisture and dampness in buildings. It defines dampness as excess moisture entering a building through floors, walls, or roofs. It identifies four main types of dampness based on moisture movement: rising damp, penetration damp, condensation damp, and outlines their causes. The effects of dampness include aesthetic issues, dry rot, corrosion, and health hazards. Remedial measures discussed include damp proof courses, waterproofing, and special techniques. Practical advice is given to reduce excessive moisture through proper ventilation and drainage, and timely repairs.

1. MOISTURE/ DAMPNESS
Prepared by: Rumi Tamakhu(700114)

2. CONTENTS
 Definition
 Sources of dampness
 Types of dampness
 Causes of dampness
 Effects of dampness
 Remedial measures
 Practical measures to avoid dampness

3. INTRODUCTION
Dampness
The excess entry or penetration of moisture inside a building
through its:
 Floors
 Walls and
 Roofs
is called Dampness.
 Dampness is dangerous both for
1. Inmates
2. Building
Dampness is the presence of unwanted moisture in the
structure of a building, either the result of intrusion from
outside or condensation from within the structure.

4. SOURCES OF MOISTURE IN BUILDINGS
SOURCE OF
MOISTURE
Liquid water
sources
leakages,
rain, fog,
snow, etc.
Water vapour
source
Pressure diffusion,
sweating, etc.
Soil
sources
Gravity,
capillarity,
absorption

5. TYPES OF DAMPNESS
Based on the movement of moisture the dampness
can be of the following four types
 RISING DAMP
 PENETRATION DAMP
 CONDENSATION DAMP

6. RISING DAMPNESS
 Capillary suction of moisture from the
ground into porous masonry building
materials such as stone, brick, blocks,
earth and mortar
 The moisture will continue to rise until it
reaches a height where, unless no
evaporation is possible, gravity takes
over and pulls it down again.
https://www.wisepropertycare.com/services/rising-damp/what-is-rising-damp/
Tied mark outside Staining inside
Tied mark inside

7. PENETRATION DAMPNESS
 The penetration of moisture through the fabric of buildings
over a period of time, usually characterized by localized
areas of damp or saturated wall/ceiling finished
 Also known as lateral dampness
 CAUSED by water penetrating through walls from the
exterior of a property due to problems within the building
structure such as:
• Absorbent bricks
• Cracks in plasterwork
• Brick jointing
• Inadequate cement & plaster mixes
• Various other situations such as internal plumbing works or
built up external ground levels
 Affect both interior and exterior wall surfaces

8. Evidence similar to that of
rising damp which
includes:
 Damp patches
 Salt efflorescence
 Mould
 Blistering of wall paint
 Deterioration of the
plasterwork.

10. CONDENSATION • Condensation is the formation
of liquid drops from water vapor
• Occurs where water in the air
inside a building condenses on
a cooler surface
• Excessive condensation in
most cases result in severe
mold growth which also creates
health hazards
• creates damp patches which
appear and disappear on
regular basis

12. Causes of dampness
Following are the main causes of dampness in a building
1. Rain penetration
2. Level of site
3. Drainability of the Soil
4. Climatic conditions
5. Defective Orientation
6. Entraped moisture in the building
7. Defective construction material
8. Defective construstion
9. Moisture originates in the building.

13. Causes of Dampness
1. Rain penetration
 It is the main source of dampness. Heavy rain of short
duration is less dangerous. rain water enters through
joints, cracks and porous bricks or stones.
2. Level of site
 Low laying building sites are effected by the depositing
surface water and underground water.
3. Drainability of the Soil
 Course grained soils like Sandy or gravely soils provides
good drainibility conditions and fine grained soils like
clay retain water and cause dampness.
4. Climatic conditions
 In cold climatic condition dampness causes due to
condensation of water vapors.

14. Causes of Dampness
4. Defective Orientation
 If building is exposed to direct rain showers and less
sun rays then it cause dampness.
5. Entrapped moisture in the building
Due Over soaked bricks and use of salty or alkaline water
results dampness in building.
7. Defective construction material
 Porous bricks, soft stones, alkaline water etc. cause
dampness of building.
8. Defective construction
 Through defective joints of parapet, copping and
masonry joints moisture can enter in the building.
9. Moisture originates in the building.
 It is due to the leakage through water supply or
sanitary system of building

15. EFFECTS OF DAMPNESS
Following are the harmful effects of
dampness in buildings.
 Building become aesthetically
poor.
 It cause dry Rot to the wooden
members provided in the
building.
 It cause corrosion of metals used
in building.
 Plaster peels off.
 Paint blistered and bleached and
the surface disfigured.
 Holes and pits are formed in
topping of floors.
 Efflorescence occurs and bricks
disintegrate and turn in to
powder.
 Un hygienic conditions in
building.

16. REMEDIAL MEASURES
 By Damp Proofing Courses (DPC)
 By surface treatment
 By water proofing construction
 By special devices/techniques

17. By Damp Proofing Courses (DPC)
 Continuous layer of impervious material between source of
dampness and building component
 Path of water up walls is blocked by builders incorporating
an impervious layer into the wall at low level ‘damp roof
courses’
 Have been made of various materials including things as
slates, engineering bricks and bitumen felt.
Classification of DPC
 Classification of Damp proofing material
 Qualities of a good Damp proofing Material
 Important places for Damp proofing materials.

18. Classification of Damp proofing material
 Flexible Materials
Material which do not crack and deform due to loadings.
 Bitumen Mastic (Mastic Asphalt)
 Bitumen felt
 Hot Bitumen
 Metal Sheets
 Rigid Materials
Materials that cannot resist transverse stresses.
 Rich Concrete
 Mortar
 Bricks
 Stone Slabs

19. Flexible Materials
 Bitumen Mastic (Mastic Asphalt)
 Hot Bitumen or Asphalt + Sand
 Applied in hot state in 1” to 2” (2 cm to 5 cm)
 Bitumen felt
 6 mm thick bitumen sheet available in roll form
 Hot Bitumen
 It is sprayed at @ 1.75 kg/m2
 Metal Sheets
Lead, copper, Aluminum sheets can be used
 Lead can react chemically with cement so should
be laid in lime mortar.
 Minimum thickness of copper sheets should be 3
mm .

20. Rigid Materials
 Rich Concrete
 1” to 2-1/2” thick layer of P.C.C (1:2:4) painted with
hot bitumen is applied
 Mortar
 Rich or fat cement mortar CS(1:3) is laid in ¾”
thickness (2 cm) as vertical DPC.
 Painted with bitumen
 Bricks
 Over burnt bricks are used in two layers in CS(1:3)
mortar
 Stone Slabs
 Two layers of stone slabs in lime cement and sand
mortar (1:1:6) is provided in areas where stone is
easily available.

21. Qualities of a good Damp proofing Material
 Impervious
 Durable
 Non disintegratable
 Stable under the loading
 Level finish
 Full coverage of wall thickness
 Availability
 Economical

24. Important places for Damp proofing materials
 At Plinth Level (in walls ) (external & Internal)
 Parapet walls
 Window sill
 Basements and Under ground Floors

25. DPC at different locations
1- At Plinth Level
2- At Parapet Walls
3- AtWindow Sills
4- Basements & Under Ground Floors

26. Fig: PLAN OF BUILDING SHOWING DPC
This is done by providing air drains and damp proof
course or dpc alone.
Sub soil drainage may also be provided.

27. AIR DRAIN
TREATMENT OF FOUNDATION’S DAMPNESS
FROMADJACENT GROUND
 This is done by providing air drains and damp proof course
or dpc alone.
 Sub soil drainage may also be provided.

28. AIR DRAIN  Narrow dry space ( 20-30 cm)
 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)
 Top of air drain is covered with
r.c.c slab or stone slab.
 dpc is done horizontally and
vertically.

29. 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.
 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.

30. DPC TREATMENT FOR BASEMENT IN DAMP SOIL

31. ASPHALT TANKING FOR BASEMENT

32. 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.
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 there is chance of excessive
uplift pressures due to soil and water table

33. DPC FOR FLOORING

34. DPC FOR ROOFING
FIG: DPC FOR ROOF

35. DPC FOR PARAPETS
FIG: DPC FOR PARAPETS AND COPINGS TO THE PARAPET

36. WATER-PROOF CONSTRUCTION FOR PARAPET

37. WATER-PROOF CONSTRUCTION FOR WATERTANK

38. SURFACE TREATMENT
 The surface treatment consists of
application of layer of water repellant
substances on the surface through which
moisture enters
 The use of water repellant metallic soaps
such as calcium and aluminium oletes
and stearates are effective against rain
water penetration
 Pointing and plastering of the exposed
surfaces must be done carefully using
water proofing agents like sodium or
potassium silicates, aluminium or zinc
sulphates, barrium hydroxide and
magnassium sulphate.
 Surface treatment is successful when
moisture is superficial

39. 3.WATER PROOFING CONSTRUCTION
 Water proofing is the method of creating a protective
layering around the building preventing the water from
seeping into the building.
 water proofing in basements is carried out so as to
prevent the intrusion of fluids or smells into the
basements.

40. Materials used for Water Proofing
Cement : Ordinary Portland cement is used for all
water-proofing works
Sand : Clean river sand should be used for
water- proofing work. If muddy, the sand should be
washed before use
Metal : Hard angular metal of sizes varying from
12mm to 20mm is used for water-proofing works
Brick bat: Brick bats should be well burnt pieces
of bricks having proper thickness

41. WATER-PROOFING CHEMICAL/POWDER
Some chemicals include
 tar/bitumen based compounds
 inorganic compounds with little percentage of chlorides
and sulphates.
 acrylic based compounds.
 epoxy resins.
 silicones.
 polysulphides and polyurethanes

42. BRIDGING OF CAVITY WALLS
 In cavity walls, water will penetrate if the cavity if
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.
4. SPECIAL TECHNIQUES/DEVICES

43. 7/19/2017Pepared by Engr Fazal-E-Jalal

44. Dampness in buildings is a risk
factor for health effects
Associations found with cough, asthma,
tiredness, airway infection
 Increased relative risk 1.4-2.2

45. Practical Advice for
Reducing Excessive Moisture*
 Fix roof and plumbing leaks right away
 Check for standing water (e.g., basement & refrig drip pan)
 Make sure rain drains away from house (& irrigation)
 Vent clothes dryer to the outside
 Ensure adequate ventilation (from outside) and
circulation (inside). Use fans that vent air to the outside
when bathing, showering, and cooking
 After flooding, remove any wet or damp material right
away and start drying (with fans). Pull up carpets.

46. THANKYOU
Prepared by: Rumi Tamakhu