Damp proof courses of rich and
dense cement concrete (1:2:4 or richer) and cement concrete floors give good
protection against white ants. The following methods also offer protection.
- A solution of ½ kg of copper sulphate in 20 litres of water in the mortar. The solution also protects wood, takes two days of steeping per 25 mm of wood thickness.
- Yellow arsenic in mortars in the proportion of : concrete 6.5 kg, masonry and plaster 0.8 kg, per 10 cu.m.
- A layer of about 75 mm graded washed sand or sand and cinders over which a sodium arsenate solution is spread. (Arsenic being a poison should not be used on surface works)
Extermination of termites in
buildings
The whole area proposed to be
occupied by the building together with an extra width of 3 m all around shall
be excavated to a depth of 15 cm and soaked with water. Spreading wet straw
over the area brings the ants to the surface. If a white-ant’s nest exists on
site, it’s presence will become evident in a few days, whereupon the nest
should be completely dug out, the queen ant destroyed and the nest flooded with
boiling hot water containing a solution of arsenic.
Recourse should be taken to
inject oil/kerosene base solvents into termite channels in woodwork and masonry
followed by sealing openings and spraying the liquid.
Termites generally do not
penetrate masonry or concrete of first class construction in which there are no
voids. Masonry with lime mortar of mix leaner than 1:3 shall not be used to be
in contact with soils where a concrete floor has not been laid. If the floor
construction has vertical joints between the floor and the plinth masonry,
these joints should be filled with heavy grade coal tar pitch to minimize the
infilterate of termites through these joint.
