A raised deck in your garden can be a wonderfully relaxing place to be, but not when you have a colony of rats scuttling around beneath its surface. If left unprotected, the shelter and shade to be found underneath a raised deck can play host to rats, mice, possums, cane toads and other dangerous and destructive vermin. As such, installing some kind of barrier to protect the space under your deck is vital.

One of the most effective ways to keep rats and other vermin from inhabiting the space beneath your deck is by installing a rat wall, a physical barrier which is placed around the base of your deck and partially buried to prevent burrowing animals from bypassing it. Traditionally, heavy bricks or concrete slabs were used to construct these walls, but stainless steel wire mesh can also be used to make a thoroughly effective rat wall. Lighter, cheaper and easier to install than a traditional masonry rat wall, wire mesh walls made from stainless steel are also thoroughly immune to rust and corrosion, so a rat wall that takes just a few hours to install can serve you well for years to come.

Choosing the right mesh for your rat walls

It goes without saying that choosing a loosely-woven wire mesh won't be much use, as rats, mice and other small vermin animals can simply slip between the gaps in the mesh. You should therefore opt for quarter or half-inch mesh (sometimes referred to as 'hardware cloth') when choosing your wall materials. You may be tempted to choose mesh that is even more finely woven, such as insect mesh; however, these ultra-fine meshes are made with very fine and delicate wires, and a determined rat can easily chew through such a fragile barrier.

Installing your rat walls

Installing a wire mesh rat wall is a relatively simple affair, with only a few steps required:

• Digging a trench around the bottom of your deck to accommodate the buried portion of the wall should be your first step. For your rat wall to be thoroughly effective it should extend at least a foot below below ground, so be sure to dig your trench suitably deep. You should also take care to make the trench wide enough, as the bottom portion of your wall will be bent at a 90 degree angle away from your deck; this prevents vermin capable of deep burrowing from bypassing the wall when they encounter it. This horizontal section of the wall is generally constructed to extend half a foot beyond your wall, so make sure to dig your trench wide enough so you have space to work in.
• Once your trench is dug, you can begin installing the wall. Using lathe screws or robust nails, attach the top end of the rat wall to the base of your deck, and roll the mesh out until it reaches the base of your trench. Once the bottom of the trench is reached you should bend the bottom portion outwards to create the horizontal section of your wall. If possible, this should all be achieved with a single roll of wire mesh, but if you need to use more than one piece you can overlap them by a few inches to prevent vermin from wriggling through any gaps.
• Filling in the trench is the final step, and this can be done with the same earth you dug out of the trench; however, adding a coarser aggregate material, such as sharp sand, will provide an extra layer of protection.