Building Defects Caused Due To Dampness

BUILDING DEFECTS-DAMPNESS

PRESENTED BY: DHRUV BASU K.V.ABHISHEK SHAHEEN NAZIF VATSALA SINHA B.ARCH.5TH YR.

Dampness Damp

is a problem in buildings. It can result in the growth of moulds and fungi, damage to the interior (and exterior) decor, wood rot, and ultimately damage to the structure of the building. Dampness occurs in properties for a number of reasons

1.Rising Dampness Caused by the absence or breakdown of a damp proof course or membrane.  It is characterized by wet patches to ground floors and walls with sometimes a white powdery 'tidemark' deposit.

POWDERY RESIDUE

2.Penetrating Dampness • Caused by such things as old brickwork that becomes porous, leaking roofs and gutters and rotted windows and doors. • Brickwork defects; Movement cracks can allow water in through the outer skin of the wall. • It is characterised by localised mould growth, discolouration to internal decoration, peeling wallpaper and sagging ceilings.

localized mould growth and discoloration.

Patches with well defined edges.

3.Condensation   Condensation is a particular problem on cold days when it causes water droplets to form on cold surfaces where there is little air movement to dry it such as in corners, behind furniture and inside wardrobes.  The lack of air movement combined with the dampness allows mould to grow on any absorbent surface such as wallpaper, plasterwork but also clothing and bedding.  How to avoid condensation? There are three basic ways to avoid or reduce condensation and its effects:

1.Produce less moisture Cover steaming pots and pans and do not leave kettles boiling . Avoid using portable gas heaters because they produce a lot of water vapor . Do not dry washing indoors except in a room with the window open.  Always vent tumble dyers to the outside air. 3.Ventilate to expel moist air Use mechanical extraction in the bathroom and kitchen and keep the doors to these rooms closed whilst in use and for a period afterwards . Keep windows slightly open to aid air movement . Leave wardrobe and cupboard doors ajar or cut breather holes to aid air movement. 

localized mould growth and discoloration.

Moisture patches

Dampness in Earth Walling As the moisture level increases at the base, the load bearing

capacity of the wall is reduced at the very position where the loading is greatest.   This can cause the wall to consolidate and spread, and the render at the base to crack and spall.   Failure to attend to the problem is likely to result in the wall eventually collapsing. 

1

5

2

3

6

7

1.Moisture can find its way into the walls if the roof covering are not adequately maintained, if the eaves overhang is insufficient, or if gutters and down pipes (where needed) are neglected.

2.Cracks in the external render will allow water ingress.  Do not repair cracks or replace rendering with strong cement based renders, but instead use a lime render matching the original as closely as possible.  Avoid using mesh, such as chicken wire or expanded metal, in renders as

2

1

distance from the corner on the adjoining elevation) may be due to lateral 5 thrust from the roof However, it may have started soon after construction as a result of drying shrinkage, and worsened subsequently 6 through weathering.  Having eliminated the causes of such cracking, the walls can be stitched across the can cracks using 6.Vegetation be damaging, with roots material closely matchingthe earth walling. penetrating and displacing the original.  Also, bees can cause severe pitting of the

the underpin course, 5 preferably at least 15Omm. In many cases, over the years the ground level has built up to an unacceptable level. Care must be taken when remedying this situation to ensure that the foundation remains adequately 7 8.If the ground around the building is covered. Each case needs excessively damp and this appears to be to be assessed on its own adversely affecting the Poor and walls, some merits. form of ground treatment may be appropriate.  This needs to be carefully designed to ensure that drainage trenches and possible shrinkage through drying of the ground do not threaten the

Effect of Dampness: Various effects (indirectly defects) , cause due to dampness in building , are mention below: •A damp building creates unhealthy living and working conditions for the occupants. •Presence of damp conditions causes efflorescence on building surfaces which ultimately results in disintegration of bricks , stones , tiles etc. and hence in the reduction of strength.

It cause bleaching and flaking of paint

which results in formation of colored patches on the wall surface. It result in corrosion of metals used in construction of building. Timber when in contact with damp conditions gets deteriorated due to the effect of warping , buckling and rolling of timber. All electrical fittings get deteriorated causing leakage of electric current with the danger of short circuit. Dampness promotes the growth of termites and hence creates unhygienic conditions in building.

Prevention of Dampness 1. Use of Damp-proofing Course: These are the layers or membranes of water repellent materials, such as Bituminous felts, Mastic asphalt, Plastic sheets, Cement Concrete, Mortar, Metal sheets, Slates, Stones, etc.

2. Waterproof (or Damp proof) surface treatment: • The surface treatment consists in filling up the pores of the material exposed to moisture by providing a thin film of water repellent material over the surface. • some of the material , as water proofing agent in surface treatment are: Sodium or Potassium silicates, Aluminium or Zinc Sulphates, Barium Hydroxide and magnesium sulphate.

3. Integral Damp Proofing treatment: • The integral treatment consists adding certain compounds to the concrete or mortar during the process of mixing, which act as barriers to the moisture penetration. • some of the compounds like chalk, talc, fuller’s earth, etc.

4. Cavity Walls (or Hollow Walls): Cavity wall consists of three main parts, namely.. 1. the outer wall or leaf(100mm) 2. the cavity or air space of 50mm to 80mm, and 3. the inner wall or leaf (min.100 mm in thickness) The provision of continuous cavity in the wall

efficiently prevents the transmission of dampness from outer wall to the inner wall…

Case studies: GDA Housing,Sector-23,Sanjay Nagar ,Ghaziabad Residence of Mr.Vinod Sharma,R-14/37,Raj Nagar,Ghaziabad. Apeejay School of Architecture and Planning, Management Block.