Do you remember when it was routine to spray for termites before pouring a slab? It was only 20 years ago- but how things have changed in the area of pre-construction termite treatments.
Probably the biggest change of all was the acceptance in the termite Standard that a concrete slab itself could form part of a termite barrier. At the same time, the long lasting ‘organo-chlorine’ chemicals being used were withdrawn and replaced with the safer termiticides that we have today- but these are registered with a service life of about 10 years only. This raised concerns about the lack of termite protection beyond 10 years in non-accessible building parts such as under slabs.
An additional concern has been the indication that the traditional system of “free-hand spraying” of termiticide had a poor track record of performance. Where was the evidence? In 2005 the CSIRO produced a termite risk map of Melbourne, based on a limited survey by Termite Action Victoria. The map and tables clearly showed that the council areas where pre-construction termite protection was mandatory, were also those that suffered the highest rates of termite infestation. In fact 25 pct of all termite infestations occurred within 4 council areas, all of which required pre-construction termite protection. Perhaps the protection helped- but it certainly did not bring home the bacon.
What was behind this poor performance is not clear, but most experienced termite specialists will tell you that the chemicals used are effective when applied fully and correctly. The blame is more likely to be the invisible nature of sprays, and the difficulty in inspecting and certifying that an application has been made to all stages of an often complex building. Parts of buildings were probably not treated. Furthermore, treated areas such as garden beds and pathways, were liable to be compromised by the subsequent landscaping and paving works that often follow the termiticide application.
We are fortunate that the dismal landscape painted above has been brightened by a new way of doing things. There is a growing range of termite protection products that can be seen, touched and inspected and the builder is spoilt for choice in picking a method that suits the building.
These products have some common features-
- They often integrate with part of the building structure such as a concrete slab, which together with the product, form a ‘termite management system’.
- These systems are ‘BUILT-IN’, and can at some stage be inspected, confirmed to be complete, signed off and certified. In an imperfect world, this is a big advantage over the invisible ‘spray’ method.
- A ‘BUILT-IN’ system is generally not as easily compromised when a new home-owner makes new garden beds or lays new paving around the home.
- They provide longer term protection, often with an expectation of 50 years of service.
- They typically come with a warranty which is subject to the building being inspected annually by a termite specialist. This is in-line with the termite Standard, and apart from inspecting for termites, it provides an excellent opportunity for home owners to be informed by the inspector about maintenance of things such as landscaping levels, ventilation and replenishment of chemical in reticulation systems. (where fitted)
Generally, ‘built-in’ products are applied so as to integrate with building parts to form a single termite barrier. It would be unusual in Victoria today to underlay a termite protection product under the entire building. Instead, the design of the building must be understood, building plans provided, and the qualities of structures such as a concrete slabs and sub-floor clearances must be specified prior to planning a termite protection system that will utilise the building components as part of the termite barrier.
- Must be designed and constructed so as not to have a 1mm crack through the slab. AS 2870 and AS 3600 are ‘deemed to satisfy’.
- Slabs with abutments to other structure, such as ‘in-fill slabs’, require protection at those margins.
- Potential holes / joins / and gaps in the slab should be independently protected.
- The external perimeter, typically at the edge rebate, should be independently protected.
- Must be 400mm clear of the ground to permit local barriers such as stump capping to comply.
- Concrete /steel stumps require no further protection. Masonry footings and timber stumps require protection, such as with capping / strip shielding.
EXAMPLES OF PRODUCTS TYPES
These were the first of the new wave of ‘built-in’ products after the old chemicals were withdrawn, and include the well established stainless steel mesh and graded stone methods. The companies providing these products did not just supply the material, but they established for the first time a comprehensive system behind the product, and trained their people to install it, inspect it and warranty it. They undertook extensive research and testing and developed a range of adhesives, sealants and fixing methods that became part of their ‘systems’ . They also had to coax the building industry away from treating termite protection as an afterthought and ‘quick spray’, and into a scheduled stage of the building process, and they provided industry training and seminars accordingly. These methods remain available today, and have the advantage of being well known throughout Victoria as well as being chemical free.
Termite reticulation systems are a convenient re-application or termiticide via an irrigation system similar to water irrigation. Some of these products were developed as the old chemicals were going and have become very well established. They are cost effective and simple to install and simple for the builder to schedule – in. They are an improvement on hand spraying chemical, and are particularly useful to enable re-application where concrete / tiled paths / patios surround a building. They require replenishment every few years, typically by the supplier, who may also provide an on-going warranty.
Treated termite membranes are typically plastic strips that have been loaded in some way with an insecticide. Brands vary in technology- some membranes sandwich a treated textile material between two thin plastic sheets, and another brand actually includes insecticide within the plastic itself during manufacture. The result is a range of products that are generally expected to last the lifetime of a building, can be readily inspected and can be installed into buildings in a range of convenient ways. They are cost effective to supply and once installed they tend to be left undisturbed to do their job for the long haul without any service requirements. Impregnated membranes are repellent to termites – which cannot contact or explore the membrane. This provides a feeling of confidence that if a membrane is inadvertently damaged during the building process, termites may not be able to find the breach. An additional security is the range of adhesives and sealants that come with most brands. These are mostly today ‘active’, meaning that they also contain insecticide, and increase the flexibility and security of these systems.
There are many other methods available, and their number is increasing continually.
SO WHAT SHOULD A BUILDER DO?
- Provide proper building plans including those for elevations and footings.
- Include termite work into the building schedule and give plenty of notice of your requirements.
- Respect the specialist’s work, and ensure that following trades do the same.
- Once the termite system is installed, ensure that the provider fixes a ‘durable notice’ in the SEC box (or sub-floor frame) and that you pass on the certificate of installation with your hand-over pack to your purchaser. This will allow the new owner to contact the termite company and register for annual inspections and warranty. Once this is done, you can sleep easy knowing that someone else’s phone will ring if termites rear their ugly heads over the long years ahead.