How many lineal metres of termite barrier does your Officer home need?

Start at the front left corner and walk clockwise. Measure each straight run at the base of the wall, not at the eave and not along the fence, and write each figure straight into your phone as you go. An 8 metre tape and a second person is quicker than a laser outdoors, because the laser struggles in bright sun against a light rendered wall.

Record every step and return, including the ones that feel too small to matter. The garage that projects 1.4 metres past the front wall adds 2.8 metres. An alfresco that steps in 3.2 metres and back out again adds 6.4 metres. Those two features alone are why owners tell us 44 metres and the tape says 58.

If you cannot get all the way around, use the satellite measuring tool in a maps app and trace the roof. Then correct it. The roof outline includes the eaves, so it overstates the wall perimeter by roughly 8 times the overhang: about 4 metres on a standard 500 mm eave, and 5 metres on a 600 mm eave. Trace it, subtract that, then check two runs with a tape to confirm you are within half a metre.

Finally, add 10 per cent to whatever you finish with. Bay windows, meter box recesses, the step at the laundry door and the little dog-leg beside the hot water unit are all real metres, and they are the ones nobody counts.

Litres of diluted emulsion. As a planning figure a perimeter trench about 150 mm wide and 300 mm deep consumes around 5 litres of prepared emulsion per lineal metre once the returned backfill is treated as well as the trench face. So 58.8 metres is about 294 litres. The registered product label sets the actual rate in litres per square metre of treated soil, and the technician converts that to litres per lineal metre from the trench dimensions on your site. Never accept a certificate that leaves the litres blank.

Drill holes through concrete. Holes go in at 200 to 300 mm centres. At 250 mm centres, every metre of concrete is 4 holes, so 14 metres of path, porch and garage apron is 56 holes to drill, inject, plug and colour match.

Bait stations. In-ground stations sit at 2.5 to 3 metre spacing around the full structure. Divide your perimeter by 3 and round up: 58.8 metres gives 20 stations. Then add 3 or 4 at the conducive points a technician will find anyway, such as a stump left from the estate clearing, a timber retaining wall, or the line of an old paddock fence. A typical Officer install lands at 20 to 24 stations.

The mixing allowance. A technician mixes about 10 per cent more than the calculation, because running 15 litres short at the last 3 metres of trench means remixing a batch and re-cleaning the tank. Anything left over goes into the final section of treated trench, never into a drain, which matters here because Officer drains to the Cardinia Creek and Toomuc Creek catchments.

The costliest sizing error here is measuring the block instead of the building. A 512 square metre Officer lot has a boundary of roughly 92 metres and a house perimeter of 59. Quoting the boundary produces a number that looks like a rip-off; quoting a bare rectangle and ignoring the garage and alfresco produces a number that has to be revised on the day. Both destroy trust that the job itself never deserved to lose.

The second is sizing only what you can see. Where an extension, a re-stump or a slab addition has been built, the junction between old and new is a separate treatment detail and it adds metres. On acreage blocks toward Pakenham Upper and Nar Nar Goon, the treated zone usually has to include piers and stumps rather than a simple wall line, which is why the estimator adds a loading for a full subfloor.

The third is treating detached structures by reflex. A colorbond shed on its own slab, 8 metres from the house, with no timber in ground contact, usually does not need a barrier of its own. It needs to be inspected, and it needs the firewood moved off the ground. Adding 30 metres of barrier around it is roughly $1,300 to $2,300 of work with very little return.

The honest constraint: some Officer homes need zero new metres. If your house was completed in the last five to eight years, the durable notice in the meter box records a complete perimeter system, and the last annual inspection came back clear, the correct answer to how much barrier do I need is none. Book the annual inspection, fix the drainage and the garden bed height, and keep the money. If your build has a reticulation loop instead, the right question is whether it can be recharged rather than replaced, which is covered on our barrier recharge page.