Dampness in Buildings, Cheat Sheet of Behavioral Economics

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DAMPNESS IN BUILDINGS

(Causes & Remedial measures)

Civil Engineering Materials

Civil Engineering Department

The University of Lahore

TOPICS

• Definitions
• Causes of Dampness
• Effects of Dampness
• Remedial measures
• Classification of Damp proofing material

DEFINITIONS

• PEELING OFF
  • This term is related to plaster and it means that

the plaster surface get disfigured.

• Blistered and Bleached
  • These term are related to Painting
• DPC (Damp proof course)
  • It is a continuous layer of impervious material

between source of dampness and building

component

CAUSES OF DAMPNESS

Following are the main causes of dampness in a

building:

1. Rain penetration
2. Level of site
3. Permeability of the Soil
4. Climatic conditions
5. Defective Orientation
6. Entrapped moisture in the building
7. Defective construction material
8. Defective construction
9. Moisture originates in the building

4. CLIMATIC CONDITIONS

In cold climatic condition dampness causes due to condensation

of water vapors.

5. DEFECTIVE ORIENTATION

If building is exposed to direct rain showers and less sun rays

then it cause dampness.

6. ENTRAPPED MOISTURE IN THE BUILDING

Due to Over soaked bricks and use of salty or alkaline water

results dampness in building.

CAUSES OF DAMPNESS

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.

CAUSES OF DAMPNESS

Remedial Measures

• By Damp Proofing Courses (DPC)
• By surface treatment
• By water proofing construction
• By special devices/techniques

By

Damp Proofing Courses

DPC

Classification of Damp proofing material

1. Flexible Materials

• Material which do not crack and deform due

to loadings.

• Bitumen Mastic (Mastic Asphalt)
• Bitumen felt
• Hot Bitumen
• Metal Sheets

2. Rigid Materials

• Materials that cannot resist transverse

stresses.

• Rich Concrete
• Mortar
• Bricks
• Stone Slabs (^13)

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/m^2
• 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.

Qualities of a good Damp proofing

Material

1. Impervious

2. Durable

3. Non disintegratable

4. Stable under the loading

5. Level finish

6. Full coverage of wall thickness

7. Availability

8. Economical

Important places for Damp proofing

materials

• At Plinth Level (in walls ) (external & Internal)
• Parapet walls
• Window sill
• Basements and Under ground Floors

Dampness in buildings is a risk

factor for health effects

Associations found with cough, asthma,

tiredness, airway infection

• Increased relative risk 1.4 - 2.