By: Aamarpali Puri
Termites are also known as white ants. Termite proofing is the treatment given to a building, to control or prevent the termite growth in the building. The termites enter into buildings through cracks, walls, pipes and floor joints etc. Once termites developed in the building area, it is very difficult and costly to finish.
Termite control in buildings is very important as the damage likely to be caused by the termites is huge. Wood is one of the cellulosic materials which termites damage, cellulose forming their basic nutrient. They also damage materials of organic origin with a cellulosic base, household articles like furniture, furnishings, clothings, stationery, etc. Termites are also known to darnage non-cellulosic substances in their search for food. Rubber, leather, plastics, neoprene as well as lead coating used for covering of underground cables are damaged by termites. The widespread damage by termites, high constructional cost of buildings have necessitated evolving suitable measures for preventing access of termites to buildings.
On the basis of their habitat, termites are divided into two types, namely (a) Subterranean or ground nesting termites, and (b) Non-subterranean or wood nesting termites having no contact with soil. The subterranean termites are most destructive and are mainly responsible for the damage caused in buildings. Typically, they form nests or colonies underground in the soil, near ground level in a stump or in other suitable piece of timber, and some species may construct a conical or dome shaped mound. These colonies may persist for many years and, as they mature, contain a population running into millions.
(i) To prevent the growth of termites, it is essential to use superior quality of material and good workmanship.
(ii) The building site should be cleared off all old tree stumps and dead wood etc.
(iii) The wooden material like door frames etc. should properly be treated.
Methods of Termite Treatments:
- Pre-construction treatments
- Post-construction treatment
- Pre-construction treatment:
Site preparation: All the waste wood, grass, strumps, roots etc. lying buried or on the surface are to be removed.
Treatment of excavated foundation trenches:
The bottom and sides of trenches up to a height of about 300 mm should be treated by applying insecticide solution (i.e. 4 litres of water with .25% to .5% of aldrin by weight or 0.25% to .5% of Heptachlor by weight) at the rate 5 litres/m2 of the surface area.
Treatment of back-fill soil:
The back-fill used to fill the trenches after the masonry walls are constructed, should be treated with .5% of aldrin or .5% of Heptachlor by might. Solution should be applied on the vertical surface of the foundation masonry at the rate of 7.5% lit/m2. If the foundation is made of R.C.C., the treatment should be started at a depth about 0.5 m below ground level and the solution in the back fill at the rate of 7.5% lit/m2 of vertical surface to be given.
Treatment of filling at plinth level:
Prior to laying of sub-grade for ground floor, the top surface often consolidated earth filling should be sprinkled with .5% of Aldrin/ Heptachlor at the rate of 5 lit/m2.
Treatment of soil along the external periphery:
The solution of .5% Aldring/Heptachlor can be injected @ 2.25 lit per metre by 12 mm diameter of 300 mm deep holes at 150 mm c/c distances.
If there is apron all along the external wall, then the chemical solution laid on consolidated earth under the apron @ 5 lit/m2.
- Post construction Treatment:
Soil treatment of foundation: – For this dig a trench about .5 m deep all along the wall drives 15 mm diameter holes in the trench at 150 mm c/c. The holes are to be filled with chemical solution. (.5% of aldrin/.5% of Heptachlor) at the rate 7.5 lit/m2 of vertical surface of the wall.
Soil treatment under floor:
All the joints/cracks of floor with walls, can be treated by drilling 12 mm dia. Holes @ 300 mm c/c all along joints and filled with the chemical solution and then the face of the holes to be sealed.
Treatment of voids in masonry:
Drill 12 mm f holes at 300 mm c/c and fill with the solution.
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