CONSTRUCTION DEFECTSAND

THEIR REMEDIES

By :-

APARAJITA GOYAL

DEFECTS AND CRACKS

• There are various defects in a building which may be caused due to dampness , applied forces and change in size

• Cracks may develop if the building material used is of low quality

• Cracks can be divided into 2 categories 1 . Structural cracks 2 . Non – Structural cracks• Cracks due to moisture changes • Cracks due to temperature variation• Cracks due to elastic deformation and creep• Cracks due to effect of chemical reaction• Cracks due to movement of ground• Cracks due to vegetation

CRACKS DUE TO DAMPNESS

• 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 metre and it will often leave a characteristic horizontal 'tide mark'. The historic city hall in Bamberg stands in the river Regnitz and its bridge remains dry without any chemical , mechanical or electronical damp-proof course

• "Rising Damp" is most often caused by damp penetration which is then absorbed by the plaster which is highly absorbant and due to the chemical reactions taking place inside the wall

SYMPTOMS

• 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 uniformely spread

throughout

IDENTIFICATION OF DAMP PROBLEMS

• 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. • Solid, that is non-cavity walls• Condensation.

• Damp proof membrane or Damp Proof course been buried by later building activities

TREATMENT

• It is suspected that the problem is condensation, then a room should be sealed off with a left running for the recommended time and then further instrument tests made.

• If the dampness has disappeared, then condensation is very likely the problem.

• Insulation of cold surfaces and/or the elimination of water vapour at source are the answers.

• The cause of the dampness must first be eliminated, by providing better drainage or fixing leaking pipes. You 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

DEFECT DUE TO LEAKING PIPE

DEFECTS CAUSED DUE TO APPLIED FORCES