In tropical climates there are particular factors that must be taken into account when deciding on the type of driveway to build compared to those in countries with a temperate or cold climate. That’s because for much of the year driveways in tropical climates will be exposed higher temperatures – and in most countries a lot more rain and higher humidity – than in cooler climates.
Aesthetics and budget are other factors that have to be taken into account when choosing the type of driveway to install.
In terms of durability, nothing beats a poured concrete driveway. It can be the most expensive option, but will undoubtedly be the longest lasting provided the base is properly prepared and compacted, and the correct amount of reinforcing steel or mesh is used.
The main difference between laying a concrete driveway in the tropics compared to temperate or cold climates is that more expansion joints need to be provided to avoid the concrete cracking.
And another is that the surface of concrete driveways in tropical climates should have a rougher finish because there is always a build-up of algae and mold in the rainy season in the tropics, which will make the surface of a smooth concrete driveway slippery and dangerous to walk on.
One way to ensure a non-slip finish and make the driveway look aesthetically appealing, is to use an exposed aggregate finish. The fine gravel that is used for exposed aggregate driveways comes in many different colours, so this enables attractive patterns to be introduced into the finishes.
Another type of concrete driveway that can be very attractive is the stamped concrete driveway. These are generally cheaper that exposed aggregate because no additional materials are required. The finish is achieved by stamping the wet concrete with shallow molds to make the surface look like bricks, pavers or cobblestones.
A variation on the stamped driveway is the stenciled driveway. Instead of using a mold, a stencil is laid over the wet concrete to create a pattern. Often more intricate patterns can be created with stencils than molds. Some companies offer custom-made stencils, but these will of course cost more.
Often various pigments are mixed into the concrete before pouring stamped concrete driveways so that the colour matches the exterior of the house or certain features of the house.
Another factor that needs to be considered when designing driveways for tropical climates, is the need for spoon drains on either side of the driveway to take water away during heavy tropical downpours.
The concrete should be laid so there is a slight fall from the center of the driveway to the spoon drains on either side. If there is not enough room for spoon drains, then an alternative solution is to install a drain down the center of the driveway and have the fall of the concrete towards the center.
However, this will collect twice as much water as the spoon drain design. So the capacity of the drain and its outlet needs to be large enough to accommodate the expected water volume during the rainy season months.
Pavers or bricks
Driveways constructed using pavers or bricks can look very attractive when new, but after a few years can become troublesome if the base layers have not been properly compacted.
It is essential when preparing the ground for a paver driveway that the driveway be excavated to a depth of 20-30 cm (8-12 in) so that sufficient base material can be laid under the layer of sand onto which the pavers will be laid.
The actual depth will depend on how soft the ground is (the softer the ground the thicker the base layer needs to be) and it is advisable to hire a motorized plate compacter to compact the base material.
Compacting by hand may work for a patio but not for a driveway, which will carry the weight of heavy vehicles. The base material must be compacted in two or three layers, no more than 10 cm (4 in) at a time.
In the wet tropics, interlocking pavers are usually a better option than bricks because they are less likely to dislodge in the rainy season. In the dry tropics, bricks may look aesthetically better.
In many countries there are ‘grass pavers’ available. These are pavers with a hole in the middle, or in a hashtag shape, enabling grass to be grown in between the pavers.
If a good quality soil mix is used with grass pavers, and they are regularly fertilized with a nitrogen-rich liquid fertilizer, a grass paver driveway can look very attractive.
However, if the grass paver driveway is not well maintained, it can quickly be overgrown with weeds and become an eyesore.
The cost of materials for a paver driveway is generally less than for a concrete driveway, but higher labor costs in some countries may mean the difference in the total price between the two is negligible.
Paver driveways are best installed with a concrete edging strip to prevent the pavers or bricks moving outwards when vehicle wheels are close to the edge of the driveway.
A cheaper alternative in temperate climates, and very common in cold climates, asphalt driveways are not so suited to tropical climates, particularly in countries where temperatures go over 40 degrees C (100F) in the summer months.
High temperatures will cause the surface of the driveway to become soft, and when vehicles are driven on the hot driveway, the weight of the vehicles may cause permanent distortions or cracks.
Cracks in the asphalt will then make the surface susceptible to damage by rain, with potholes eventually appearing just as they do on major highways.
Asphalt does have some advantages over concrete though. It’s about 30-40 percent cheaper to install, and if it does have to be repaired, only the top layer has to be replaced, meaning that it can be restored to an ‘as new’ looking state at a much cheaper price than a damaged concrete driveway.
In rural areas of the tropics, where the length of the driveway may be much longer than in suburban areas, a gravel driveway may be the most cost effective option.
The type of gravel to be used will depend on what materials are available locally. Colored gravels will always look more attractive than aggregates that are grey in colour (called ‘blue metal’ in some countries), but often the cost will determine the type of gravel used.
Whilst a cheap gravel driveway can be constructed just by laying gravel over the ground, a more aesthetically pleasing and easier-to-maintain driveway will be the result if the driveway is first excavated to a depth of at least 10 cm (4 in) and edged with concrete or bricks.
If the gravel is available in different sizes, a bottom layer of a coarse grade (for example three-quarter inch) should be laid and compacted first, and then a layer of a finer grade gravel placed on top.
Even in suburban areas, gravel driveways can look very attractive if materials are available to match the colour of the house.
The big advantage of gravel driveways is that aside from occasional weeding, they are easy to maintain, and may in fact be the best option in gardens where there are many big trees, because gravel driveways don’t interfere with the root systems of the trees.