Adding sleepers to your garden

There are a few things you might want to consider before you build a sleeper project.

• Depending on the project you’re undertaking, we recommend drawing up a design before you begin work. This ensures you have enough materials, helps minimise waste, and gives you a visual guide for assembly.
• Think about the physical location of your project and the drainage of the surrounding area. Hardwoods are very heavy to manoeuvre if you have a project at the far end of your garden. But they tend to have better drainage when used as retaining walls or for raised beds.
• If you’re joining full-length sleepers without cutting them, check the sawn ends before you start. You may find that they’re not quite square and need to be planed or sanded for accuracy.

Hardwoods such as oak are slower to grow. This makes them denser in structure, heavier to handle and usually more expensive than softwoods. They’re highly durable and more resistant to decay without treatment. 

Hardwood sleepers have an untreated lifespan of around 30 years and can last for up to 150 years with good care. Rich in colour and with a prominent grain, hardwoods tend to be full of moisture. Because of this, they’re more prone to cracking and shrinking over time.

Softwoods, such as pine, are lighter than hardwoods. They have more uniform square cut ends, making them easier to drill, cut and manoeuvre. Less dense and with a lighter grain, they’re a budget-friendly choice. 

You can buy them with or without pressure treatments, but they’re more susceptible to decay, so regular treatments and finishes help increase their expected lifespan to around 15 years.

Left untreated, both softwoods and hardwoods will silver over time. This is due to the natural tannins being bleached by water and the sun. 

Circular saw: versatile, rapid and high-powered, a circular saw makes accurate cuts for precision projects. If you can, go for a model with a laser guide, rip fence and dust collection system.

Universal handsaw: ideal for fast cutting through wood. Go for a handsaw with an ergonomic handle, steel blade and triple ground teeth.

Combination drill: versatile and portable, an all-purpose drill will cover a broad range of project needs. Choose a cordless model for ultimate flexibility.

Impact driver: this features enhanced torque, variable speeds, and controlled pulses to drive fixings into the toughest surfaces.

Drill bit set: a combination set will cover most eventualities.

Belt sander: remove rough textures and smooth over large surfaces with ease. Choose a model with integrated dust extraction and keep a selection of sanding belts to hand.

Quick square: combining a combination square, try, and framing square in one, this tool makes marking out quick and accurate. You can also use it as a fence for your circular saw.

Tape measure: choose a retractable option with clear markings.

Spirit level: Check your surfaces are perfectly level and scribe straight lines using the long edge.

You may also need the following, depending on your sleeper project:

• Assorted sandpaper

• Hammer

• Wood brush

• Sleepers

• Dowel

• Exterior timber screws

• Timber plates and brackets

• Wood dye

• Wood stain

• Wood paint

• Wood preserver

• Wood oil

• Landscaping fabric or polythene sheeting

• Staple gun

• Heavy-duty staples

• Castor wheels

You need to take safety into account too, so make sure you have protective goggles, a dust mask, ear protectors, and gloves.

When cutting sleepers, we recommend using a circular saw for accuracy, precision and speed. You’ll find in most instances that the blade is not deep enough to cut through the depth in one pass. Instead, you need to rotate the sleeper and cut it in sections.

Note: we would not recommend cutting sleepers with a chainsaw or reciprocating saw. A reciprocating saw produces wavy cuts. A chainsaw can be dangerous, inaccurate and messy for an inexperienced user. If you have trouble cutting your sleepers, it’s worth contacting a specialist company.

Consider the tolerance, runout and alignment of your power saw blades. Depending on your tools, dimensions may adjust by 2-3mm. For consistency, ensure you cut on the same side of the scribed line each time.

Because you must rotate the sleeper, use a perfectly straight edge as a cutting fence to guide your saw blade. A small piece of offcut timber is ideal. You can also use your quick square, holding it firmly as you run the circular saw shoe against it.

To find the correct placement for an offcut saw fence, measure from the circular saw blade to the edge of the shoe. Add this measurement to your first cut measurement, then measure out on your timber.

Mark the measurement with a crow’s foot, then use your quick square to scribe a straight line across the width.

Align the offcut against the scribed line, and fix it in place with a couple of screws. Make sure this is on the same side of the line for consistency.

Make the first cut by running the saw shoe against the offcut fence. Turn on your circular saw blade before it touches the timber to avoid snagging.

Then unscrew the offcut, rotate the timber and repeat the process.

A universal handsaw can be used to cut through softwoods, and is useful for cutting through central sections that a circular saw blade might not reach.

Once you’ve cut the timber, it’s a good idea to sand and treat the cut ends with a good quality wood preserver. Brush on a generous amount to each cut end to extend the life of the timber.

Softwoods can be fixed with steel or zinc screws. Piloting is not always necessary, but this depends on the quality of your impact driver. We recommend heavy-duty timber screws, also known as lag or coach screws. Hex drive timber screws are a great choice. You can countersink the head of the screw for a flush finish and fill the holes with dowel plugs for a traditional look.

If you choose to work with hardwood, you’ll need to use stainless steel screws. The natural tannins in hardwoods can corrode non-ferrous fixings over time. Because hardwoods are denser, you will also need to pilot the screw holes each time using a multipurpose drill bit or auger wood bit.

Whichever fixing you use, ensure your screws are a third longer than the depth of your timber. Use a drill bit to pilot your timber that is the same diameter and length as your screw.

Pilot your first sleeper length before butting it up to make the join. Use your tape measure and quick square to mark a straight line and decide on your fixing placements.

Pilot through the first fixing holes. Move the timber into position so it’s butted up against your second timber length.

Sleepers are best constructed on a firm and level surface such as soil, grass, decking, or concrete; however, you should still use a spirit level to ensure the surface is as level as possible. 

Depending on your project, you may wish to use sand, cement, or timber offcuts to level things out. For retaining walls and steps, it’s also worth using a string line to check your levelling.

When you’ve butted your timber joins together, pilot through the first holes again so the bit penetrates partway into the next length.

Ensure the joint is snug and flush. Use an impact driver to secure the fixings through each hole so the screw penetrates the adjoining sleeper. Make sure the screw head is sunken or flush to the surface.

When building sleepers in layers, overlap the right-angled corners for added stability and strength. Place your length or frame on top of the first layer so the joins are overlapped like a brick wall. Once the joints are secured, drive fixings down through the layers.

If your sleepers are used as planters, raised beds, borders, or retaining walls that support large amounts of soil, you may need extra support.

Using corner brackets and fixing plates adds further stability to internal layers.

You can use timber screws to secure fixing plates across timber lengths, and brackets to reinforce corner joints. Using timber dowel to peg through sleeper lengths provides additional strength and a traditional look. We recommend using dowel alongside timber screws to ensure the sleepers are really secure.

Use an auger bit that’s the same diameter as your dowel, and longer than the width of your sleeper. Pilot down through the centre of the timber so the auger goes partway into the length below.

Cut your dowel sections slightly longer than your auger bit. This allows for any variance in the length of the pilot holes.

Taper one end of each dowel section to slightly round it off. This helps the dowel enter the second timber length.

Always use a wooden mallet for manipulating wood into place and hammering dowel. If you do not have a mallet, use a metal hammer and an offcut to strike against. This stops the metal hammer from ruining your wood surface.

Bang each dowel peg into place using your offcut length as a striking board.

When you’re happy the stakes won't go in any further, remove the excess with a universal saw. Hold the blade so it’s flush with the surface of the timber.

Use a belt sander and a coarse grit paper. Working with the grain, run the belt sander slowly over the sleepers until each surface is smooth.

Use fine grit sandpaper to help expose the natural grain.

Add a small chamfer to the edges using a palm sander, a belt sander or a wood planer. This removes the high-profile edges to create a smoother finish.

Wood dye changes the colour of your sleepers while allowing the natural grain to show through. Simply brush on a couple of generous coats.

To add an antique look, apply a coat of wood dye then sand back the surface to add a weathered effect. Wood dyes are best maintained every few years to combat fading.

Available in a broad spectrum of colours, wood stain offers weather protection while enhancing the natural textures of your timber.

Easy to apply and with water-repellent qualities, you can sand back the surfaces for a natural look.

Wood oil protects timber against UV rays and helps slow the silvering process. Penetrating the surface to create a natural sheen, oil replaces the natural oils lost through weathering. It is a good choice for keeping sleeper furniture in great condition and should be reapplied every year.

Exterior paints are available in bold, neutral, and garden shades. They are the easiest way to transform your sleepers and zone your spaces. You can expect wood paints to look great for around 5 years.

Always check the manufacturer’s label before applying any preservatives, paints, stains or treatments.

For a secure build, start by creating a level trench and placing your sleepers on a firm base of soil, sand, or hardcore. Check the surface with a spirit level, then overlap your corners like brickwork. Join them securely using heavy-duty timber screws or wooden dowels.

The safest and most accurate way to cut a sleeper is using a circular saw with a laser guide. Because sleepers are thick, you’ll need to mark a straight line, use an offcut of wood as a fence, and rotate the sleeper to cut it in sections. Always wear safety goggles, gloves, ear protectors, and a dust mask.

To stop your sleepers from rotting over time, treat all cut ends with a generous coat of wood preserver. If you’re building raised beds or planters, line the inside with landscaping fabric or polythene sheeting and secure it with heavy-duty staples to create a moisture barrier.