Termite resistant design
Termites cause more damage to Australian houses than fire, floods and storms combined - damage that is not covered by household insurance.
How termites can move from a nest to a house
Here are ways that you can reduce the chance of termites causing major damage to your home: (from building commission website)
- Check your property and building regularly for termite activity to reduce the risk of damage
- Plumbing leaks, drainage problems and roof leaks should be addressed promptly, as termites are attracted by damp conditions
- Garden beds should not be built up against walls, as this allows termites an undetectable entry point to the building
- Do not block or cover sub-floor ventilation with garden beds or paving
- Do not stack materials against walls, as this can allow termites to enter without early detection
- Sub floor areas should be well ventilated and vents should not be obstructed
- Storage of cellulose products in the sub floor space should be avoided
- Use termite resistant timber for works around the property, including retaining walls
- Use metal stirrups for verandah and gateposts
- Clean and check timber decks regularly
- Do not build rainwater tanks up against walls, as this may allow termites an undetectable entry point to the building
Fragile termites exposed from under mud tube
The building permit notes that the Abdallah House is in an 'area designated as subject to termite infestation' and that protection is required from termites in accordance with Australian Standard 3660.1. Apparently, I must employ both physical and chemical techniques in order to comply with the standards - but in order to find out what the standards are I need to spend $142 to get an electronic copy of the book.
Concrete is an effective barrier to termites, unless it cracks. Cracking in a concrete slab is more likely to happen if it was not prepared properly, which is very common in the age of quick construction - hence underslab termite treatments are often used. Because we compacted the sand fill, vibrated the wet concrete and poured it during the coolest time of the year, we are less likely for the concrete slab to crack - and so fulfill the criterea for a physical barrier according to the Australian standards. If we didn't do that we may have had to drill holes throughout the slab and inject termite treatment - an expensive and messy job, with an unsightly finish. Areas have been left uncovered above the slab insulation for termite inspection.
Concrete stumps with ant caps are another deterrant that we employed. There are chemically treated ant caps that could have been used, had I know before we did the job. Good clearance (400mm) between the ground level and bearers and joists ensure that there is good access for regular inspections as well as allowing the possibility for good ventilation.
Around all areas with ground contact to the house I have dug out a small trench which we are looking at filling with sand mixed with a chemical that will adhere to termites that are in contact with it and infect a termite nest within 15-20m. The chemical is water based and does not smell - and is more expensive than standard treatment which is rather toxic and repels termites rather than infect their nest. Chemical treatments like this need to be replaced every 5 years or so.
Termite treated timber has been used for all framing, this is guaranteed for 25 years. When treated timber is cut and is left exposed it needs to be retreated with an areosol spray.
I was recently told that termite live in acidic conditions, which is why they are so prevalent in Australia. Apparently lime is a good deterant as it is alkaline, which could be a good alternative to harsh chemicals.