How wide is termite infestation in Hornsby Heights?

okay !

Termites are everywhere especially if the area is surrounded by bushland which is the case in most of the areas in Sydney. Hence a periodic termite inspection is recommended to avoid any surprises. We have been living here for the last 20+ years without any issues and have had termite control system in place.

Yes, termites are around if you live near bushland. You just need to be vigilant. Many houses such as ours are protected by "granite guard" which is built-in to the construction and provides tiny granules of granite as a barrier which the termites do not like to cross. Not perfect I'm sure but has worked for us for 20+ years.

There are reported to be hundreds of species of termites and they are an important part of the eco system in the bush and help break down dead or decaying timber. Apparently only a few species are prone to access and damage homes and it’s all in the design, maintenance and regular inspections of the home and property.
At least a 12 monthly visual check from a pest profession is recommended on any home in the Hornsby Heights area and some more frequently. In my experience I would say about 20% of homes in the area have had some experience with termite activity, from a few fence posts to a full wall eaten out, mainly because the owners have not taken up this design, maintenance and inspections for termites recommendation.

The majority of homes in the area will have some kind of past termite activity, being so close to the bush this is a common thing. However, most home owners are quite pro-active when safe guarding against termites, they have regular checks and ensure that the damage doesn't effect the structure of the home.