IS 6313 (Part 2) treats the soil with a chemical emulsion while the foundation is open. In the 2001 edition the rate is 5 litres per sq m on trench bottoms and plinth fill and 7.5 litres per sq m on backfill and the outer perimeter, at a strength of 1 per cent. BIS has revised the standard since, so confirm the edition.
What does IS 6313 cover?
IS 6313 is the Bureau of Indian Standards code of practice for anti-termite measures in buildings. It has three parts:
- Part 1 covers constructional measures, which are design details that keep termites out.
- Part 2 covers pre-constructional chemical treatment, applied to the soil as the building goes up.
- Part 3 covers treatment of existing buildings.
The figures in this post are from the 2001 edition of Part 2 and Part 3 and the 1981 edition of Part 1, read in the public copies on law.resource.org. BIS lists later editions: secondary sources say the 2013 edition dropped lindane and added imidacloprid, and that a 2022 revision added bifenthrin. This post could not read those editions, and a 2024 Mazagon Dock tender repeats the same litre rates as the 2001 text. Ask your applicator which edition and chemical he follows, and read the current standard.
No West Bengal rule on termite treatment was found for this post. IS 6313 is the national standard, and your municipality or lender may name it in the sanction or the contract.
Which chemicals and what strength?
The 2001 edition names chlorpyrifos 20 EC (IS 8944) and lindane 20 EC (IS 632), each diluted to 1.0 per cent active ingredient by weight. A Gujarat Industries Power Company tender gives the mixing as one part of the 20 per cent concentrate to 19 parts of water for a 1 per cent emulsion. The standard warns against using the chemical where wells or other water supplies could become contaminated, so tell the applicator where your well or borehole is.
How much goes where?
The 2001 edition sets a rate for each surface:
| Surface | Rate |
|---|---|
| Bottom and sides of foundation trenches, to about 300 mm | 5 litres per sq m |
| Backfill against the foundation, vertical surface | 7.5 litres per sq m |
| Top surface of the plinth filling | 5 litres per sq m, with holes 50 to 75 mm deep at 150 mm centres |
| Apron soil | 5 litres per sq m |
| Perimeter soil | 7.5 litres per sq m |
| Expansion joints | 2 litres per metre of joint |
How is the treatment applied on site?
The standard sets a sequence, and the owner or supervisor can check each step:
- Start the treatment when the foundation trenches are ready for the mass concrete.
- Rod the earth at 150 mm centres so that the liquid soaks in.
- For RCC foundations, begin 500 mm below ground level.
- At the junction of wall and floor, cut a channel 30 x 30 mm and pour 7.5 litres per sq m of wall.
- Treat a 150 mm band around pipes, to a depth of 75 mm.
- Do not treat in rain or in wet soil, and do not disturb the treated barrier afterwards.
Ask the applicator for a signed record of each stage, with the date, the area and the volume used. The site supervision checklist shows where this check fits in a house build, and the guide to soil tests and foundation types covers the foundation stage that the treatment follows.
What does a termite protection plan cover?
Chemical treatment is one layer. Part 1 of IS 6313 says anti-termite constructional measures are effective only if both external and internal protection are adequate. It calls for a concrete apron around the building, a continuous sub-base under walls and coarse sand under the floor, so that termites find no easy path through a crack.
Timber is what termites reach once they are inside, in door frames, windows, furniture and roof members. Protect it with the plan the standard describes and with details that keep it dry. The guide to damp and seepage in Kolkata houses explains why moisture matters.
What if the building already exists?
Part 3 of the 2001 edition covers post-construction treatment with the same chemicals at 1.0 per cent. The chemical is pumped at 2.25 litres per linear metre through holes drilled about 300 mm apart near the plinth wall, and floor and wall junctions get at most 1 litre per hole. This is a repair and it is less certain than a treatment done at foundation stage.
Who guarantees the work?
IS 6313 gives no guarantee period in the parts read for this post. Tender practice is to ask for 10 years. A Mazagon Dock specification says the contractor has to furnish the guarantee for 10 years, and a BHEL tender asks for a 10-year service guarantee in writing. A homeowner can ask for the same, in writing, with the chemical, the strength and the areas treated. Keep the certificate with the building papers.
The cost of treatment per sq ft is not published in the sources read for this post, so ask two or three applicators for quotes on the same drawing.
What should an owner ask the applicator?
A short list covers the points where treatment usually goes wrong, and each item follows from the standard above:
- Which edition of IS 6313 and which chemical, with its strength as a percentage.
- The litres per sq m for each surface, and the total volume for your plot.
- A date for each stage, so that the foundation is not closed before treatment is done.
- The written guarantee period, and who honours it.
- Where the well, borehole or tank is, so that the chemical keeps clear of it.
What next?
Put the termite treatment in the specification, and have the supervisor check it before the foundation is closed. The studio’s site supervision service covers checks of this kind, and its architecture service covers the specification. To discuss a house, use the contact page.
