Termites can ‘attack’ any type of building, whether, RCC or masonry, old or new or basement. They make their way even through a small gap of 0.5mm by constructing mud-tubes to get into the building. Moisture in the building and wood that is in direct contact with soil are favourable factors for termite infestation.
Termites are silent destroyers and a big threat to most constructions, be it houses or office buildings. By the time the infestation is detected, extensive damage may have already occurred to the building and furniture. There are a few options available for the protection of buildings from the subterranean termite infestation. Physical barriers like termite shields, constructional measures, and inert barriers like sand or stainless steel mesh or chemically treated plastic sheets could be used. However, many of these systems are not popular in India as they are either expensive or cumbersome to use and cover all stages of constructions.
There are two types of treatment options – one is preventive treatment implemented during construction and two, curative treatment carried out for termite infestations post construction.
Chemical Barrier Method of termite control is widely used in India during the construction of the building at plinth level and hence this is called pre-construction anti termite treatment. This treatment creates a chemical barrier or a treated zone between the building and the soil from where termites are likely to enter. Be it, load bearing masonry building or RCC framed structure, the treatment is carried out in different stages of construction. However, the critical success factor would be whether the chemical barrier / treated zone created is complete, covers all areas and is continuous. Residual life of chemical in the soil also needs to be factored in.
Planning, co-ordination and proper implementation of termite management procedures can only be completed by the engineer. In addition to the treatment by professional pest control operator, following precautionary measures on site would help:
- Remove dead trees, stumps, logs or roots from the building site
- Remove debris, especially wooden members / pieces of scaffolding which are not in use
- Provide proper drainage, ventilation and lighting to the buildings and site
- Correct immediately any leaks of pipes thereby avoiding moisture and dampness. Remember that moisture or dampness is one of the favourable conditions for termite infestation in the building
- Avoid as far as possible keeping wood or wooden members in direct contact with the soil
- Avoid possible any soil filling above the treated chemical barrier
- Chemical barrier created should not be disturbed by removing treated soil from the site. If it happens, take step immediately to restore the disturbed barrier by contacting concerned pest control operator (PCO)
- Treatment should not be carried out when it is raining or when the soil is saturated with sub-soil water. The chemical should be applied when the soil is dry and is in absorbent stage. After the treatment, immediate steps showed be taken by the engineers to cover the treated layer by laying PCC or Tremix
Presently, chemicals approved by CIB & RC (Central Insecticide Board and Registration Committee of Govt of India) for termite control in Buildings are Chlorpyriphos, Imidacloprid, Bifenthrin & Ethion.
The chemical is chosen by taking in to account the safety of human beings on site, environment, toxicity and effectiveness. Preference is given to Imidacloprid due to its odourless nature and requirement in very low dosages. It is less toxic than others.
Creation of a chemical barrier at the foundation stage called as Pre-construction Anti-termite Soil Treatment consists of applying chemical in the form of an emulsion spray on the soil surface before laying PCC / concrete. Pressure pumps are used for the treatment.
Stages of Pre Construction Treatment
For load bearing masonry structures, the treatment starts from the trenches and for RCC Framed Structures, the treatment starts from the 50cm from ground level.
Pre-construction Anti Termite treatment is the only “effective as well as economical” tool available as on date. It is effective because the treatment allows creating a complete chemical barrier / zone between the soil below the ground and the super structure.
Precautions against termite
Anti-termite treatment is a continuous process and is essential to control the quality during the treatment, i.e. during application of the chemicals.
- Chemical used are mixed with water at recommended ratios only. Over dilution should not be allowed.
- PCO / Service provider should give basic knowledge about Termite Control, its stages and chemical dosages to engineers, so that they can control the quality.
- Professional PCOs should be appointed so that treatment can be carried out with correct dosages, at right stages. In case of any re-infestation during the warranty period, the PCO can provide required service on call.
- Any soil filling (for terrace garden / flower beds / mud fusca, etc.) above treated layer needs treatment or else termites can build a colony in such added soil and can cause infestation / damage.
Post construction treatment
Termite control measure in existing building involves drilling holes in the entire wall and floor junction and injecting it with termiticide. The chemicals injected in these holes are absorbed by the walls and retained to create a chemical barrier / zone. This treatment has its limitations in creating uniform and complete chemical barrier. Hence, is also called as a blind treatment. Many times construction material does not absorb and retain the chemicals which may result in leaving gaps within the barrier through which termites can re-enter. The drilled holes are sealed with cement once the treatment is done.
Termite detection and termite management has always been a challenge even for professionals. A thorough inspection of an infested building is very critical for understanding the root-cause and extent of the damage. Visual inspections would be limited in any modern building as large hollow spaces are inaccessible for inspections due to interior design features such as panelling and false flooring / ceiling.
This is where the latest technologies in termite detection come handy. Tools like, ‘Termatrac’ which is a micro-wave based termite detection tool are very useful for non-invasive detection of termites in structures. Such tools can help locate the source, extent and location of infestation.Shankar Ghuge Pest Control (India) Private Limited Mumbai