Building a timber retaining wall is a great way to add character, privacy and value to your home. This project can be completed by someone with basic carpentry skills. The first step is to determine how tall you would like your retaining wall to be and then figure out how many boards will be needed. If you have access to salvaged wood, this will help reduce the cost of building your wall.
Once you’ve determined how tall you want your retaining wall to be, decide on how far apart each board will be spaced. The distance between boards should depend on what type of plants are going in front of the wall and how much space they need for growth. If you’re using timber for this project, it’s best to use untreated Southern Yellow Pine or Douglas Fir because these woods are resistant against rot and decay.
The retaining wall is built from treated pine sleepers, which can be bought from any hardware store.
The retaining wall is built from treated pine sleepers, which can be bought from any hardware store. Sleepers are the most common choice for building a retaining wall because they’re strong and affordable. Other options include concrete, brick and stone.
The first step is to dig a trench into which you’ll lay your sleepers in a staggered pattern (see diagram above). The width of the trench depends on the height of your wall: for every meter of height add 10cm to your base width, but don’t make it wider than 50cm. Make sure that you dig down below the frost line so that it doesn’t shift during winter! You should also ensure that your trench is at least 15cm deeper than where you want your lowest point on top of ground level; this will allow rainwater to drain away naturally without seeping through gaps between joints in materials used as part of construction work
The most important part of the retaining wall is the base, so don’t skimp on it.
The most important part of the retaining wall is the base, so don’t skimp on it. Your base needs to be strong enough to support the weight of your sleeper wall and its contents. It also must be level and stable with a solid foundation that runs deep into your soil. The best way is to dig out about 300mm – 600mm (12 inches – 24 inches) of soil for a good depth at each end of your retaining wall’s footing.
If you have rocky or sandy soil you may need to add some gravel underneath these areas as well as compacted road base or bedding sand over top them before building up your walls using bricks or other materials such as sandstone, slate or rocks can be used instead
You need to dig a trench that is 300mm deep and 300mm wide for the first row of sleepers.
Digging a trench is the first step in building a timber retaining wall. The trench needs to be 300mm deep and 300mm wide, so you’ll need to measure these dimensions out before you dig.
Once you’ve dug the trench, you can level the bottom of it with some base material – usually gravel or pea shingle. If necessary, add more soil at this stage too. Once this is done, lay your sleepers on top of the ground in three rows.
Fill the bottom of the trench with compacted road base or bedding sand.
Now you’re ready to fill the bottom of the trench with compacted road base or bedding sand. This will help prevent water from seeping into the soil, and will also ensure that your sleepers don’t sink into the ground too far. However, ensure that this base layer is compact before you place any sleepers on top of it—you can rent a compactor from Bunnings if needed.
You should fill this trench for the whole length of your retaining wall; then place your first course of sleepers directly on top of it (and use a spirit level to make sure each sleeper is perfectly even along its length).
The first course of sleepers should be placed directly on the base.
The first course of sleepers should be placed directly on the base. The base material can be road base, sand, gravel or concrete. A good rule of thumb is to use a material which has the same strength as your sleepers; for example if you are using 9×9 timbers then use concrete for its strength or if using 16×16 timbers then use gravel.
The easiest method is to lay down a level layer of compacted road base or sand and then place the sleepers on top so that you don’t have any gaps between them. The next step would be to fill any voids in between each sleeper with more compacted road base or sand until all voids are filled completely and then finish off by carefully leveling off with a rake so that it’s nice and smooth
For drainage, you’ll need to lay a layer of coarse gravel behind the sleeper before putting it in place.
Before you lay the first sleeper, ensure that it’s level, straight and at the correct height. Check that each of your sleepers is of a similar size and length too, as they should all be approximately the same height and length.
Once you’ve put down a layer of gravel behind each sleeper, continue with another layer in front until you reach the required height for your wall. At this point, you can start digging away at the soil in between each sleeper to create drainage channels for rainwater to flow through (you can also use stones instead of gravel).
When choosing where to dig, remember that you want any water which flows over or under your wall to drain away from other structures such as buildings or driveways.
Stagger the sleepers so they’re not all in line – this will increase their strength by spreading out any ground pressure that might occur.
Staggering the sleepers will increase their strength, as well as make the wall look better. By staggering them, you’ll prevent ground pressure from transferring all at once to one sleeper and causing it to fail. This also works in reverse – if you stagger your sleepers, it makes the wall less likely to lean or bulge outwards from uneven pressure.
Place a level on top of each sleeper to make sure it’s flat and even along its length. You may need to cut some sleepers with a circular saw to get them the right size.
- Place a level on top of each sleeper to make sure it’s flat and even along its length.
- You may need to cut some sleepers with a circular saw to get them the right size.
- Cut from both sides of the sleeper at once, keeping them clamped together until you get through both sides. This will ensure that they are exactly the same length, so there is no visible gap where they join.
- If you don’t have access to a circular saw, you can use an axe or hatchet instead (but be careful)
Use galvanised nails to secure each sleeper in place, hammering the nails through one side only – this will keep them free to expand in hot weather.
Use galvanised nails to secure each sleeper in place, hammering the nails through one side only – this will keep them free to expand in hot weather.
If you’re building a timber retaining wall that’s over 1 metre high, take care to avoid any damage from falling branches or other hazards. You’ll also need permission from your council before you start work on any kind of landscaping project like this one.
You should use treated pine sleepers for your timber retaining wall as they are good value for money and durable enough to last a long time without rotting away or splitting apart at the seams. This type of timber is easy enough to cut down into smaller pieces too so if there is not enough space between two posts then simply cut some more off until they fit perfectly into place
With help from Bunnings Warehouse, we show you how to build a timber retaining wall.
Bunnings Warehouse is a leading hardware retailer with a wide range of timber sleepers and other products that can be used to build a retaining wall. Their website is also full of helpful advice on how to get started building your own timber retaining wall.
Bunnings Warehouse is an Australian company with locations across Australia and New Zealand as well as parts of Europe. You can find your closest store by using the Bunnings Warehouse store locator, or browse their online catalogue for inspiration and advice on how to design your own garden bedding scheme
