Near coastal living has many benefits, however it does also provide for a near ocean house or shack a challenging environment with high maintenance issues. Structural hot dipped Galvanised steel products are the bare minimum that can survive within a high salt air environment within 500m of the coast and stainless steel is recommended if your property is situated on the sea front. These requirements are for structural, sheeting and fastening materials.
Colorbond Ultra is the only Colorbond steel wall sheeting product that can be used between 500m to 1km away from the waters edge, or if closer, stainless steel roofing and wall sheeting is your only choice. If your looking at buying standard Colorbond sheeting, you will need to be at least a kilometre away from the surf for the sheeting to survive. The same guide lines will apply to fencing products too.
Termites and Asbestos related problems are an expensive issue, that cannot be ignored when looking at a shack to purchase. Termites can make your shack unsaleable and the repair costs can be extreme. Your insurance company will generally classify termite damage as preventable and therefor a maintenance issue, hence no cover. Asbestos containing older houses and shacks built prior to 1984-1985 have the added issue of requiring specialised removal and dumping requirements if any maintenance or renovation work is done to the eaves or wet areas of the dwelling. Considering most houses are likely over time to renovate the bathrooms, this is another expense that needs to be thought of. 
If you require further information to the suitability of steel cladding and the environmental implications of near coastal living, I recommend you contact the manufacturers of these products prior to obtaining quotes for building work. The cheapest quote for work, probably does not include the correct recommended sheeting or fasteners.
My web page below has important warnings regarding handling asbestos areas.
 https://www.integrityhouseinspections.com/useful-links-and-asbestos-related-articles.html

As a pest inspector, I have the qualifications and experience to locate issues within the house that is being inspected.
My pest training was completed in 2018, consisting of the training courses CPPPMT3008 Inspect for and report on timber pest and CPPPMT3010 Control timber pests.
I have been trained and certified to operate my Termatrac radar unit, that is used to locate termite movement in walls. This is an expensive piece of equipment, that is carried to every house inspection.
This unit is calibrated yearly, to ensure its efficiency.
Pest inspections are best done while doing the building inspection, as every part of the house is accessed that can be. 
The photo above, is of a termite damaged wall that has already been replaced by a builder, however termites have returned and are still attacking the window and wall framing.
I am not Pest Management qualified, as I do not wish to spray or treat termites, my only interest is to advise a home purchaser of issues such as shown above.
If you choose to purchase the house after termites or termite damage has been found it is your choice, as is how the situation is to be managed. It can be baiting, spraying, trench soaking, foams or powder poison treatment.
I will often recommend in my reports that an invasive inspection be done, to the purchaser. This consists of further inspections done by removal of sections of the wall or ceiling, however the home owner must give permission.
This may be done by the Vendor at his cost, as he may want to show that the termite issue is minor for the sale to go ahead with you. Or you may simply pull out of the sale at this point during your cooling off period.
I do not perform invasive inspections, as termites should be treated immediately once discovered, if immediate treatment is not done, the termites may retreat back into the ground and move to a new location within the house.
The choice of paying and additional $150 for a pest inspection is money well spent.