New to the Wet Tropics? Here are 5 Important Things to Consider
The Cairns Region is within the Wet Tropic zone, which means it has particular climatic conditions that make it quite different to places in drier and cooler environments. The main differences in Cairns compared to other regions, particularly through the “wet season”, are intensity and amount of rainfall, extremely high humidity levels and minimal daily temperature variation.
There’s no doubt North Queensland is a beautiful area – reef and rainforest abound, virtually right in our backyards, so it’s no wonder many southerners flock to the tropics to escape the cold winters of the southern states and gain a more laid-back lifestyle. But if you’ve decided to make that commitment and are considering purchasing a property in Far North Queensland, there are a few things to keep in mind before making an offer.
- Roof Drainage/Plumbing – In Cairns and the surrounding areas, rainfall can be intensive for days on end. It is not unusual for the Cairns region to experience the equivalent of a southern city annual rainfall in just a few days. Roof drainage and associated plumbing therefore needs to be capable of coping with these intense rainfall periods with gutters and downpipes needing to be somewhat oversized compared to other regions in Australia. If the drainage/plumbing is not able to cope with the rainfall, the house could experience internal flooding and damage to walls and the structure. Often gutters or downpipes are allowed to overflow onto surrounding ground, and if this is the case then specific attention should be paid to ground drainage (refer below).
Another factor to be conscious of is blockages in downpipes and drains. This could simply be as a result of organic matter collecting, particularly if trees are close to the dwelling. If the downpipes or drains are blocked this may be the cause of visible internal water staining in the ceiling or down the walls. While the solution is cheap and easy- to unblock the drains- the damage caused could be costly to fix. A good quality gutter guard can be a real advantage, so if it's already installed at a property you’re keen on, that’s a plus.
Ground drainage and tree roots
- Ground Drainage – similar to roof drainage, the grounds surrounding the dwelling need to be able to cope with intense prolonged rainfall periods. No installed underground drainage can quite simply mean that water will pool around the house, possibly seeping into the footings and walls. Poor water run-off can compound this problem (the surrounding ground slopes towards the building, rather than away from it).
Look for properties that already have in-ground drainage installed to assist in transporting the water away from the footings and walls, or factor installation into your budget when considering a home without it.
Cairns has many suburbs where the soils have a reasonable clay content and are not very free-draining, and the underground water table is quite high. If it’s a dry time when you’re looking at a property, the most reliable way to get information about how the grounds deal with our torrential rain is to talk to the neighbours and ask them if the property tends to flood – you’ll more than likely find they’ll be happy to have a chat!
- Vegetation – in the Tropics, with a combination of high rainfall, extreme humidity and warm temperatures, plants grow very quickly. With this in mind it is important that vegetation is trimmed back regularly and kept well maintained, especially if it is directly against a wall or eave. If not cut back the vegetation can readily become dense, hard up against the walls. If this is allowed, vegetation can encourage moisture and mould.
Also, any trees or plants with extensive root systems that are permitted to grow uncontrolled close to a structure can adversely affect its foundations. This can happen by either:
- The roots sucking the moisture from the ground during drier periods which then causes the founding soils to dry out with a potential to lead to settlement of the structural footings. This can then lead to cracking in walls and pavements; or
- Roots growing into the joints in the footings or walls. As they grow, they expand leading to cracking, impacting the structural integrity of the building.
- Corrosion (rust) – in humid tropical environments corrosion, or rust, can be a major concern. This mainly occurs in steelwork that is exposed to moisture. Generally, steelwork is protected by a coating such as paint or galvanising. When the integrity of the coating is affected this allows moisture to make direct contact with the steel which then will more than likely lead to corrosion. Once corrosion starts it causes expansion of the steel surface which then leads to further deterioration of the coating – and thus ultimately leading to a total breakdown of the protective coating. The resulting stain is usually the result of the brown iron-oxide that is produced through the corrosion process. This staining could be evident in such areas as the roof cladding or in steel structural elements such as balcony posts and balustrades.
If the corrosion is extensive the structural integrity may be compromised which may require significant work to repair. If detected early enough, even though there might be a lot of rust staining, the fix may simply be a clean back to sound steel material followed by re-coating (eg. painting).
Ventilation – in the Cairns region during summer the humidity can be uncomfortably high. To help both from an ease of living point of view and to minimize build-up of moisture, it’s important to have good ventilation throughout your home. There are two schools of thought when it comes to ventilation and keeping cool – to use air conditioning, or not to use air conditioning. If you choose not to use the air con 24/7, cross ventilation is the ideal manner to promote air flow which will then minimize the accumulation of moisture and reduce condensation. In order to achieve this, doors and windows should be openable across from one another facilitating the crossflow of air. It is important for these opening windows and doors to have mesh protection both from a security and insect perspective. Good quality ceiling fans are also a must.
Sub-floor ventilation can assist with both a cooling effect as well as assisting with prevention of the build-up moisture. This is why, in the absence of modern-day air conditioning it was common for houses to built on an elevated open frame allowing free flow of air underneath (the typical old “Queenslander”).