The document discusses common defects found in buildings such as cracks and dampness. It categorizes defects into pre-construction, during construction, and post-construction. Cracks can be structural or non-structural, and are caused by factors like drying shrinkage, thermal movement, elastic deformation, creep, chemical reactions, and foundation issues. Dampness is usually due to penetrating damp from gaps or rising damp without a proper damp proof course. Preventive measures include proper design, materials, construction practices, and addressing the root causes of defects.

1. SUBMITTED TO:- SUBMITTED BY:-
AR. MANOJ JAIN TOSHNIDHI GUPTA
MOHD. YUSUF
KAUSHAL TIWARI

2. In construction defects are mainly categorized into three
categories:-
 PRE CONSTRUCTION
 DURING CONSTRUCTION
 POST CONSTRUCTION (After construction)
The common defects in the buildings are:-
 CRACKS
 DAMPNESS

3.  Cracks in building are a common occurrence and it is important to
understand the causes and the measures to be taken for their prevention.
 Tensile stress are produced due to restraint to contraction movements.
 If these stresses exceed the tensile or shear strength of the material cracks
develop.
 In a tropical country like India, there is a large variation of atmospheric
temperature and humidity, hence it would necessary to avoid materials which
expand or contract considerably due to thermal and moisture movements.
 And design of the structure is so that to minimize restraint to contraction or
expansion of the material.

4.  STRUCTURAL CRACKS- These occur due to incorrect design,
faulty construction or overloading.
 NON-STRUCTURAL CRACKS- These are mostly due to internally
induced stresses in building materials.
Structural cracks
Non-structural cracks

5. Type Width
Thin
Medium
Wide
< 1 mm
1-2 mm
> 2 mm

6. Vertical
Horizontal
Diagonal
Straight
Toothed
Stepped
Map pattern
Random
Uniform
throughout
Narrow at one
end and gradually
widening at the
other

7.  Main causes of occurrence of cracks in buildings are as follows:
 DRYING SHRINKAGE
 THERMAL MOVEMENT
 ELASTIC DEFORMATION
 CREEP
 CHEMICAL REACTION
 FOUNDATION MOVEMENT AND SETTLEMENT OF SOIL.
 GROWTH OF VEGETATION.

8.  Drying shrinkage is defined as the contracting of a hardened concrete mixture
due to capillary water, this causes an increase in tensile stress which may lead
to cracking and warping.
 FACTOR CAUSING DRYING SHRINKAGE
 Cement and water content,
 Maximum size, grading and quality of aggregates,
 Presence of excessive fine in aggregates,
 Chemical composition of cement,
 Temperature of fresh concrete and relative humidity of surroundings.

10.  All materials more or less expand on heating and contract on cooling .
 The thermal movement depends on a number of factors such as temperature
variations, dimensions, coefficient of thermal expansion and some other
physical properties of materials..
 It is mainly the external walls especially thin walls exposed to direct solar
radiation.
 It can be avoided by introducing expansion joint, control joints and slip
joints.

12.  The temporary change in length, volume or shape produced in a elastic
substance by a stress
 Structural components of a building undergo elastic deformation due to dead
load and the live loads.
 When the walls are unevenly loaded with wide variations in stresses in
different parts, excessive shear stress is developed which causes cracking in
walls.

13.  Creep is the tendency of a solid material to move slowly or deform
permanently under the influence of mechanical stresses.
 It can occur as a result of long term exposure to high levels of stress that are
still below the yield strength of the material.
 Factor affecting creep:-
 Influence of aggregate.
 Relative humidity.
 Size of member.
 Applied stresses
 Effects of creep:-
 Increasing the deflection in larger span beams.
 Buckling of slander columns
 Buckling of cladding in tall buildings

14. Buckling of slander columns
Due to creep

15.  Certain chemical reactions in building materials results in appreciable
increase in volume of materials. The materials taking part in reaction also
become weak and lose strength .
 Common instances of chemical reaction are:-
 Sulphate attack on cement products.
 Carbonation of reinforcement and brickwork, and
 Alkali-aggregate reaction.

17. FOUNDATION MOVEMENT AND
SETTLEMENT OF SOIL
 Shear cracks in buildings occur when there is large diffferential settlement of
foundation due to one of the following causes:
 Unequal bearing pressure under different parts of the structure,
 Bearing pressure being in excess of bearing strength of the soil,
 Low factor of safety in the design of foundations,
 Local variations in the nature of supporting soil, which remained undetected and
could not be taken care of in the foundation design at the construction.

19. GROWTH OF VEGETATION
 Roots of a tree generally spread horizontally on all sides to the extent of
height of the tree above the ground and when trees are located in the vicinity
of a wall, these should be viewed with suspicion
 They can cause cracks in walls due to expansive action of roots growing
under the foundation.

21.  Do not let trees grow too close to buildings, compounds walls, etc. If any
saplings of trees start growing in fissures of walls etc. remove them at the
earliest opportunity.
 If some large trees exist close to a building and these are not causing any
problem, as far as possible, do not disturb these trees if soil under the
foundation happens to be shrinkable clay.
 If from any site intended for new construction, vegetation including trees
have been removed and the soil is shrinkable clay, do not commence
construction activity on that soil until it undergone expansion and stabilized
after absorbing moisture in at least one rainy season.

22. GENERAL MEASURES FOR PROTECTION OF CRACKS..
The measures for prevention of cracks could be broadly grouped under the following main sub
heads :-
a) Selection of materials:-
Good quality of building materials according to the specification if used that will minimize the
cracks in the building.
b)Specifications for mortar and concrete:-
The ratio of the mortar and concrete should be according to the prescribed design. Care should
be taken that the coarse aggregate, fine aggregate should be free from silt suspended impurities
and the mix should be homogeneous, well mixed and contain no excessive of water.
c) Drawing and Design of the building:-
While doing the construction work care should be taken that foundation of the building should
not be laid on loose /muddy soil. The mortar, M S steel reinforcement should be according to the
design.
d) Good Construction practices:-
It is necessary that work proceed uniformly in all part of building. The workmanship should be
according to the prescribed norms and best practice in the building construction.

23. e)Weather Effect:-
 The construction work should be avoided in very hot and dry weather, and
during very low temperature also.
 In general quality of water, sand ,Bajri , mixing of mortar ,quantity of water in
mix , socking of bricks and workmanship have great effect on construction
work. If possible the subsequent items of construction should be done after
the drying of work previously done

24.  Cracks in masonry walls- Cracks in walls generally get localized at weak
sections, such as door and window openings or staircase walls.
 In external walls of buildings, shrinkage cracks generally run downward from
window sill to plinth level an from window sill on an upper story to the lintel
of a lower story.
 Preventive measures- Shrinkage cracks in masonry could be minimized by
avoiding use of rich cement mortar in masonry and by delaying plaster work
till masonry has dried after proper curing and has undergone most of its
initial shrinkage.
 Masonry work done with composite cement-lime-sand mortar (1:1:6, 1:2:9 or
1:3:12), which are weak, will have lesser tendency to develop cracks because
shrinkage in individual masonry units gets accomodated to a great extent in
the mortar itself.

27.  Penetrating damp is the most common form of dampness in buildings.
Dampness occurs as a result of water ingressing horizontally through gaps in
the building structure.
 Rising damp describes the action of ground moisture rising up a masonry wall
by capillary action.
 It potentially occurs where there is no damp-proof course (DPC) or where the
DPC has been damaged or bridged. Theoretically, moisture can rise up the
wall to a height of a meter.
 "Rising Damp" is most often caused by damp penetration which is then
absorbed by the plaster which is highly absorbent and due to the chemical
reactions taking place inside the wall

28.  Dampness tends to cause secondary damage to a building.
 The unwanted moisture enables the growth of various fungi in wood, causing
rot.
 Plaster and paint deteriorate and wallpaper loosens.
 Stains, from the water, salts and from mold, mar surfaces.
 Externally, mortar may crumble and salt stains may appear on the walls.
 Steel & iron fasteners rust.
 It may also cause respiratory illness in occupants.
 In extreme cases, mortar or plaster may fall away from the affected wall.
 The cracks developed as even and uniformly spread throughout

29. DEFECT DUE TO LEAKING
PIPE

32.  Roof defects such as faulty flashing, cracked or missing slates or
tiles.
 Faults in the brickwork or masonry such as missing or cracked
pointing. Porous bricks or stones.
 Missing or defective mastic around windows and doors.
 Blocked weep holes.
 Missing or defective trays in cavity walls.
 Condensation.
 Damp proof membrane or Damp Proof course been buried by later
building activities

33.  The cause of the dampness must first be eliminated, by
providing better drainage or fixing leaking pipes. We can also
install a physical or chemical DPC.
 Then, any affected plaster or mortar must be removed, and the
wall treated, before replacing the plaster and repainting.
 Proper DPC must be provided and all the joints must be
properly sealed