Aussie Industrial Fix-its

When it comes to fencing that's decorative without sacrificing security, it's hard to beat good old fashioned timber. However, while a wooden fence can be just as durable against the attentions of home invaders as metal or concrete, it cannot resist the elements in the same way, and a few simple precautions will need to be taken to ensure your fence doesn't fall victim to them. One of the best and simplest ways to extend the life of your timber fence is with the installation of gravel boards.

What are gravel boards, and how can they protect my fence?

Ideally, no part of a wooden fence should have any contact with the ground beneath. This is because prolonged soil contact can cause wood to degrade, as moisture from the soil leeches into the wood and creates a haven for wood-destroying moulds and fungi. Soil-dampened wood is also more vulnerable to the attentions of termites and other wood-boring insects, so a physical barrier between the soil and your fence panels can be very helpful. Gravel boards are designed to function as this physical barrier, and are placed at the bottom of your fence, flush with the ground.

What kind of gravel boards should I choose?

Gravel boards are usually made of one of two materials, both of which are thoroughly resistant to soil damage:

• Timber: Unlike the timber that makes up your fence, timber gravel boards are pressure-treated prior to sale. Pressure treatment involves placing the wood in a vacuum chamber with a number of preservative compounds, and leaves the gravel board extremely resistant to mould and insect attack. Using wooden gravel boards can leave you with a more consistent overall look to your fence, and is less visually jarring than concrete gravel boards. However, pressure treatment tends to discolour wood with a distinctive dull grey, so finding exact matches for your fence wood may be impossible.
• Concrete: Concrete gravel boards are virtually immune to the deleterious effects of soil contact, and can be expected to last for at least as long as the fence itself does. They are naturally unaffected by insects, and provide an extra layer of tough security at the bottom of your fence. However, they are generally more expensive to purchase, and their weight can make them difficult to install, particularly under very long or angled fences. 

What else should I look out for when choosing gravel boards?

Besides the materials you use, you also have a couple of other choices to make when purchasing gravel boards:

• Should I use gravel boards supplied with my fence? Many pre-fabricated fencing kits come with timber gravel boards, which are designed to match the colour of the fence wood as closely as possible. These gravel boards can be replaced with concrete boards if you prefer the extra durability, but if you choose this option you may have problems with fitting—many pre-fabricated fences are slotted to allow easy installation with the gravel boards they are supplied with.
• Should I allow animals through? Some gravel boards are sold as 'animal-friendly', and contain gaps to allow small creatures to enter your garden. However, people living in areas that have problems with pests such as mice or bullfrogs may not want this option, for obvious reasons.