Dampness in Buildings, causes, and remedies.ppt

Dampness in Buildings, causes, and remedies

1. Dampness in BuildingsDampness in Buildings
Causes of Dampness in Causes of Dampness in
BuildingsBuildings
Remedial measuresRemedial measures

2. TopicsTopics
•DefinitionsDefinitions
•Causes of DampnessCauses of Dampness
•Effects of Dampness
•Remedial measuresRemedial measures
•Classification of Damp proofing Classification of Damp proofing
materialmaterial

3. DefinitionsDefinitions
•DampnessDampness
–The excess entry or penetration of moisture inside a building The excess entry or penetration of moisture inside a building
through its through its
–FloorsFloors
–Walls andWalls and
–Roofs Roofs
is called Dampness.is called Dampness.
Dampness is dangerous both forDampness is dangerous both for
InmatesInmates
BuildingBuilding
•Due to dampness the building become unhygienic.Due to dampness the building become unhygienic.
•Dampness in buildings is a risk factor for health Dampness in buildings is a risk factor for health
effects.effects.

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

5. DefinitionsDefinitions
•Peeling offPeeling off
–This term is related to plaster and it means that the This term is related to plaster and it means that the
plaster surface gets disfigured.plaster surface gets disfigured.
•Blistered and Bleached
–These term are related to PaintingThese term are related to Painting
•DPC (Damp proof course) (Damp proof course)
–It is a continuous layer of impervious material It is a continuous layer of impervious material
between source of dampness and building between source of dampness and building
componentcomponent

6. Back

7. Causes of DampnessCauses of Dampness
•Following are the main causes of dampness Following are the main causes of dampness
in a buildingin a building
1.1.Rain penetrationRain penetration
2.2.Level of siteLevel of site
3.3.Drainability of the SoilDrainability of the Soil
4.4.Climatic conditionsClimatic conditions
5.5.Defective OrientationDefective Orientation
6.6.Entraped moisture in the buildingEntraped moisture in the building
7.7.Defective construction materialDefective construction material
8.8.Defective construstionDefective construstion

8. Causes of DampnessCauses of Dampness
1.1.Rain penetrationRain penetration
•It is the main source of dampness. Heavy rain of short It is the main source of dampness. Heavy rain of short
duration is less dangerous. rain water enters through duration is less dangerous. rain water enters through
joints, cracks and porous bricks or stones.joints, cracks and porous bricks or stones.
2.2.Level of siteLevel of site
•Low laying building sites are effected by the depositing Low laying building sites are effected by the depositing
surface water and underground water.surface water and underground water.
3.3.Drainability of the SoilDrainability of the Soil
•Course grained soils like Sandy or gravely soils provides Course grained soils like Sandy or gravely soils provides
good drainibility conditions and fine grained soils like good drainibility conditions and fine grained soils like
clay retain water and cause dampness.clay retain water and cause dampness.

9. Causes of DampnessCauses of Dampness
4.4.Climatic conditionsClimatic conditions
•In cold climatic condition dampness causes In cold climatic condition dampness causes
due to condensation of water vapors.due to condensation of water vapors.
5.5.Defective OrientationDefective Orientation
•If building is exposed to direct rain showers If building is exposed to direct rain showers
and less sun rays then it cause dampness. and less sun rays then it cause dampness.
6.6.Entrapped moisture in the buildingEntrapped moisture in the building
•Due to over soaked bricks and use of salty or Due to over soaked bricks and use of salty or
alkaline water results dampness in building. alkaline water results dampness in building.

10. Causes of DampnessCauses of Dampness
7.7.Defective construction materialDefective construction material
•Porous bricks, soft stones, alkaline water etc. Porous bricks, soft stones, alkaline water etc.
cause dampness of building.cause dampness of building.
8.8.Defective constructionDefective construction
•Through defective joints of parapet, copping Through defective joints of parapet, copping
and masonry joints moisture can enter in the and masonry joints moisture can enter in the
building.building.
9.9.Moisture originates in the building.Moisture originates in the building.
•It is due to the leakage through water supply It is due to the leakage through water supply
or sanitary system of building.or sanitary system of building.

11. Effects of DampnessEffects of Dampness
•Following are the harmful effects of dampness in Following are the harmful effects of dampness in
buildings.buildings.
–Building become esthetically poor.Building become esthetically poor.
–It causes It causes dry Rot to the wooden members provided in the to the wooden members provided in the
building.building.
–It cause corrosion of metals used in building.It cause corrosion of metals used in building.
–Plaster peels off.Plaster peels off.
–Paint blistered and bleached and the surface disfigured.Paint blistered and bleached and the surface disfigured.
–Holes and pits are formed in topping of floors.Holes and pits are formed in topping of floors.
–Efflorescence occurs and bricks disintegrate and turn in to Efflorescence occurs and bricks disintegrate and turn in to
powder.powder.
–Un hygienic conditions in building.Un hygienic conditions in building.

12. Remedial MeasuresRemedial Measures
•By Damp Proofing Courses (DPC)By Damp Proofing Courses (DPC)
•By surface treatmentBy surface treatment
•By water proofing constructionBy water proofing construction
•By special devices/techniquesBy special devices/techniques

13. ByBy
Damp Proofing Damp Proofing
CoursesCourses
DPCDPC

14. Classification of Damp proofing Classification of Damp proofing
materialmaterial
•Flexible MaterialsFlexible Materials
•Material which do not crack and deform Material which do not crack and deform
due to loadings.due to loadings.
–Bitumen Mastic (Mastic Asphalt)Bitumen Mastic (Mastic Asphalt)
–Bitumen feltBitumen felt
–Hot BitumenHot Bitumen
–Metal SheetsMetal Sheets
•Rigid MaterialsRigid Materials
•Materials that cannot resist transverse Materials that cannot resist transverse
stresses.stresses.
–Rich ConcreteRich Concrete
–MortarMortar
–BricksBricks
–Stone SlabsStone Slabs

15. Flexible MaterialsFlexible Materials
–Bitumen Mastic (Mastic Asphalt)Bitumen Mastic (Mastic Asphalt)
•Hot Bitumen or Asphalt + SandHot Bitumen or Asphalt + Sand
•Applied in hot state in 1” to 2” (2 cm to 5 cm)Applied in hot state in 1” to 2” (2 cm to 5 cm)
–Bitumen feltBitumen felt
•6 mm thick bitumen sheet available in roll form 6 mm thick bitumen sheet available in roll form
–Hot BitumenHot Bitumen
•It is sprayed at @ 1.75 kg/mIt is sprayed at @ 1.75 kg/m
22
–Metal SheetsMetal Sheets
–Lead, copper, Aluminum sheets can be usedLead, copper, Aluminum sheets can be used
•Lead can react chemically with cement so should be laid Lead can react chemically with cement so should be laid
in lime mortar.in lime mortar.
•Minimum thickness of copper sheets should be 3 mm .Minimum thickness of copper sheets should be 3 mm .

16. Rigid MaterialsRigid Materials
–Rich ConcreteRich Concrete
•1” to 2-1/2” thick layer of P.C.C (1:2:4) painted with hot 1” to 2-1/2” thick layer of P.C.C (1:2:4) painted with hot
bitumen is appliedbitumen is applied
–MortarMortar
•Rich cement mortar CS(1`:3) is laid in ¾” thickness (2 cm) Rich cement mortar CS(1`:3) is laid in ¾” thickness (2 cm)
as vertical DPC.as vertical DPC.
•Painted with bitumenPainted with bitumen
–BricksBricks
•Over burnt bricks are used in two layers in CS(1:3) mortarOver burnt bricks are used in two layers in CS(1:3) mortar
–Stone SlabsStone Slabs
•Two layers of stone slabs in lime, cement and sand mortar Two layers of stone slabs in lime, cement and sand mortar
(1:1:6) is provided in areas where stone is easily available.(1:1:6) is provided in areas where stone is easily available.

17. Qualities of a good Damp Qualities of a good Damp
proofing Materialproofing Material
1.1.ImperviousImpervious
2.2.DurableDurable
3.3.Non disintegratableNon disintegratable
4.4.Stable under the loadingStable under the loading
5.5.Level finishLevel finish
6.6.Full coverage of wall thicknessFull coverage of wall thickness
7.7.AvailabilityAvailability
8.8.EconomicalEconomical

18. Important places for Damp Important places for Damp
proofing materialsproofing materials
•At Plinth Level (in walls ) (external & At Plinth Level (in walls ) (external &
Internal)Internal)
•Parapet wallsParapet walls
•Window sillWindow sill
•Basements and Under ground FloorsBasements and Under ground Floors

19. Difference of Bitumen and Difference of Bitumen and
AsphaltAsphalt
•Bitumen can be found in Nature.Bitumen can be found in Nature.
•Asphalt is a manufactured product, Asphalt is a manufactured product,
produced by refining crude oil by produced by refining crude oil by
heating at 300 heating at 300
oo
C in a distillation C in a distillation
column.column.
•Naphthene base crude oils are suitable Naphthene base crude oils are suitable

20. Naphthene base crude oilsNaphthene base crude oils
•Crude oil containing asphaltic materials Crude oil containing asphaltic materials
but very little or no paraffin wax. This but very little or no paraffin wax. This
type of oil is suitable for making type of oil is suitable for making
gasoline, lubricating oil and asphalt. It is gasoline, lubricating oil and asphalt. It is
also called asphalt-base crude.also called asphalt-base crude.

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