CHECKING BUILDING LEAKAGE

Although adequate care has been taken by providing weatherproofing of roofs, leakage may occur with time due to lack of proper maintenance. Leakage of roof due to rain water may spoil the materials stored in the room, may damage the electrical circuits, may wet the walls, etc. Leakages may occur in different types and different parts of a roof which are discussed below.

Leakage in Sloping Roofs

All parts of sloping roof are to be checked for leakage. It is difficult to repair after construction, particularly tiled roofs. It is generally recommended to apply waterproofing coating at the construction stage itself. Tiled roofs leak during heavy rain due to lack of this precaution.

Other sloping roofs like folded plates, shells, etc., are made out of concrete. These roofs would not have been compacted properly due to sloping surface. During normal rains there is no problem of leakage. During heavy rains, water may seep through the concrete and tend to leak. A cement coating may fill the porous concrete followed by a waterproofing coating may stop the further leakage.

Leakage of Flat Roofs

Following preventive measures and repairs may be undertaken to prevent leakage.

1. During construction stage itself, flat concrete roofs are to be cured perfectly. Any leakage noticed at this stage can be rectified easily. All surfaces can be given a coat of hot blown asphalt after curing.
2. Adequate slope may be given to the drain pipe joints such that stagnation of water is prevented.
3. Wherever the horizontal surfaces meet the vertical or inclined faces, fillets are to be provided. The gap formed with time has to be closed periodically.
4. All the entry points of the rain water should be checked and should not be blocked by leaves, wastes, etc.
5. Weathering courses, like flat tiles, laid on the roof should not crack. If cracks are found they should be closed immediate by grouting or otherwise.
6. Very porous concrete slabs may have to be grouted.

Leakage Through Junction of Walls and Sunshades

This is very common place where the leakage occurs which are to be checked and rectified as discussed below.

1. At the construction stage itself, proper slope and drainage arrangements are to be checked. Any architectural features made over sunshade should not give room for stagnation of water. A throating at the bottom end of sunshades shall make the water to drip properly.
2. In long sunshades there is a possibility of cracking at the ends. Such cracks make room to flow of water on the walls. These cracks should be filled with bituminous or elastomeric compounds. Top of sunshade should be kept clean always, particularly before the onset of monsoon.

Leakage Through Wall Cracks

All the external cracks found on walls should be deepened to 5 mm and filled with paintable sealant. In order to keep the external walls crack-free, waterproof cement or external paint may be used. Walls containing air-conditioning or other electrical connections may be painted with silicon paint to prevent wetting of walls during rains.