How to Construct a Sleeper Bed
Constructing a raised bed out of railway sleepers is amazingly straightforward. Think lego or wooden building blocks. Very quick & simple, with little tools needed. Creating these sleeper beds is also a very creative way of adding personality to your garden as the design and style of them really comes down to how you would like them to look. Remember, if you have any queries about this, or any of our How To's, feel free to contact us on 01942 720777, Facebook, or Twitter.
1) Choose where your raised bed will go
Choose the best place for your raised bed, taking into account if you want to sit or stand next to it, or if you want both sides to be accessible.
2) Lay the railway sleepers on the ground.
Place the sleepers in the rectangle or square shape that you desire, making sure the corners of the sleepers meet up at 90° angles, like putting together a big picture frame. Many people simply lay them down directly on the earth, grass, deck or concrete, but we would recommend using a foundation of hardcore or concrete, however both options will be suitable. Also keep in mind creating some sort of drainage for the raised bed, unless you want to make a raised pond!
3) Fasten them together
Fasten the sleepers together with screws, making sure the screw goes about 50mm (2”) deep into the adjoining sleeper. We recommend 2 screws per corner as a good rule of thumb.
If you have placed the railway sleepers on the ground on their wider edge, then again simply screw them together at the 90 degree corners, allowing at least 50mm (or 2") of the screw to go into the adjoining sleeper. You will obviously need to screw through more of the railway sleeper than on the narrow edge option. The one exception is if you are intending to have a second layer. In this case, you don't have to attach the first layer to itself. Simply place the second layer on top of the first (remembering to overlap the joints) and simply screw through the second layer into the first layer below) Repeat if you want a third layer. Again, at least two screws per sleeper end is a good solid formula. You have now created a structure that is interlocked.
4) Stack and fix a second layer (if you want the raised bed to be higher)
If you want a second or a third layer, simply repeat stage 2 & 3, apart from you are placing the second or third layer of railway sleepers on to the already positioned first layer. Once you've done that, you will have two or more layers sitting on top of each other, but not attached TO each other. Simply now fasten the layers together with a screw that goes through the top layer to the layer below. If you don't want this to be seen, screw at 45 degrees on the inside of the raised bed, through side of the top layer into the layer below. Alternatively, you can use a batten or metal strip to fasten the different layers together. The whole structure is now interlocked.
If you are stacking the sleepers horizontally on their broadest side, e.g. on the 250mm width of a 250mm x 125mm sleeper, then all you need to do is to overlap the joints of the sleepers, from layer to layer, like building a brick wall, and fasten each layer to the layer below with timber lock screws or similar. You have now created a structure that is interlocked, and could be picked up in one piece by a crane, if you had the inclination!
5) Attach a plastic membrane.
Some landscapers choose to fix a plastic sheet on the inside of the raised bed, to create a barrier between the wet soil and the railway sleeper. Occasionally people will even use heavy duty plastic refuse bags, but normally landscapers use a thicker heavy-duty plastic that won't degrade in the soil.
6) Fill with soil
Before you fill with bags of compost, top soil or manure, it might be worth considering putting stone / bricks / hardcore etc.. on the bottom to encourage drainage. (Many people construct raised beds as a useful way of getting rid of / hiding unwanted bits of rubble etc...!) The great thing about using raised beds is that you can fill them with whatever type of soil that best fits your planting. e.g. lime hating rhododendrons, camellias, azaleas and heathers require a more acidic soil. Raised beds are more likely to loose soil nutrients sooner than ordinary beds, so ideally, a mix of 50 per cent mix of garden soil and 50 per cent peat or substitute compost with extra fertilizer should give you good results for your raised railway sleeper beds. You may need to top up your railway sleeper raised bed with soil or compost again in 12 months.
To improve keeping moisture in the bed, you can apply a top surface of your choice such as wood chip, bark or pebbles. The soil in the raised bed can take time to settle and may need topping up – this could take a few years in the highest of raised beds so some plump for just planting annuals or vegetables to start with and leave permanent plants for a later time.
7) Fill with plants!
Now you are ready to fill your sleeper bed with whatever plants or vegetables you desire.