In brief: Build a wooden deck by first creating a load-bearing base from bearers or steel bearers. Then lay the supporting battens at the correct spacing. Finally, screw the decking boards down with the correct gap between them. Choosing the right timber, ensuring adequate ventilation and allowing a slope of around 2% for water drainage are key. With careful planning and solid tools, this is a manageable weekend project.
Your plan for the perfect wooden deck
A wooden deck transforms your garden into an extension of your living space. You can build it yourself. This saves money and gives you maximum design freedom. Success depends on thorough preparation.
First, check the local conditions. Will the planned area be in full sun or shade? This affects your choice of timber. Measure the area carefully. Sketch a plan with dimensions.
Calculate your budget realistically. The cost of high-quality decking boards and a solid substructure will be the biggest expense. Do not forget accessories such as screws, washers and connectors. Also allow for tools you may need to hire.
The biggest source of errors when building a deck is rushing. Allow at least one long weekend for assembly alone. Add several days to prepare the ground.
Choosing the right ground conditions
The ground supports everything. A firm, level and permeable base is essential. Loose soil or topsoil are unsuitable. They settle over time.
Excavate the area to a depth of around 20-30 cm. Compact the ground with a vibrating plate. Add a 15 cm layer of crushed stone or gravel. Compact this sub-base thoroughly as well.
Cover the crushed-stone layer with a robust weed-control membrane. It prevents weeds from growing through the gaps in your deck. The membrane must remain permeable to water.
Important note
Before starting work, check whether utility lines run through the area you have excavated. Contact your utility provider or local authority building department for information. Accidentally damaging utility lines is expensive and dangerous.
How do you build a stable substructure?
The substructure is the skeleton of your deck. It must support the weight of the boards, furniture and people. At the same time, it provides ventilation and the required slope.
You have two tried-and-tested systems to choose from: a traditional bearer frame made from treated square timber, or a modern system with adjustable steel or plastic bearers on pad foundations.
The bearer frame requires precise woodworking. Steel bearers are easier to level and provide optimal ventilation. The option you choose depends on your skills and budget.
Planning the slope correctly
Without a slope, water pools on your deck. The timber rots faster. Plan a constant slope of 1-2% away from the house.
For a 4-metre-long deck, a 2% slope means a height difference of 8 cm. Mark these heights with stakes and a taut string line. Align all supports exactly to this string line.
For steel bearers, adjust the feet accordingly. With a timber frame, cut the support points to the correct height. Keep checking the slope with a spirit level as you work.
Additional advice
If your deck is not attached to the house but stands freely in the garden, plan the slope in one direction. Then create a small drainage channel or bed at the lowest point to carry the water away.
Which decking boards are right for my project?
There is a wide range of decking boards to choose from. Your decision affects the appearance, durability, maintenance and price. In general, you can choose between solid timber and composite materials.
Solid timber decking boards made from native softwoods such as larch or Douglas fir are affordable and natural. They require regular maintenance. Tropical hardwoods such as Bangkirai or Cumaru are highly durable, but more expensive and harder to work with.
WPC decking boards (Wood-Plastic-Composite) are made from wood fibres and plastic. They are dimensionally stable, easy to maintain and do not splinter. Their appearance is more uniform than natural wood. They are a popular alternative in the garden and outdoor living sector.
Many people underestimate the weight and movement of timber. Buy your decking timber several weeks before building and store it in a sheltered but well-ventilated place at the future installation site. This allows it to acclimatise.
These wood-effect garden tiles offer a quick alternative. They can be laid directly on a level surface without an elaborate substructure. The set is suitable for small areas or temporary solutions.
Choosing the right thickness and length
The thickness of the boards determines the joist spacing. For 21 mm-thick boards, choose a joist spacing of 40 cm. With 26-28 mm-thick boards, you can use a spacing of 50-60 cm.
Buy boards in a length that minimises waste. Plan your layout so joints land on a joist. Stagger the joints from row to row, like brickwork. This increases stability.
How do you lay decking boards correctly?
Now comes the visible part. Laying the decking boards requires care. Start at the longest, straightest edge of your deck, usually against the house wall.
Lay the first decking board and align it perfectly. It serves as the reference for all subsequent rows. Secure it with two screws at each support point. Use stainless steel screws with a Torx drive.
Place a 5-8 mm gap spacer between each decking board. This gap is essential. It allows water to drain away and gives the wood room to expand. Work your way across the deck, row by row.
Pro tip
Pre-drilling prevents the decking boards from splitting, especially when working with tropical hardwoods and near the ends. Use a wood drill bit that is slightly thinner than the screw shaft. This saves effort and protects the material.
How to handle joins and edges
Longer decks require joins. Always position them centrally over a support batten. Cut the decking boards with a jigsaw or circular saw. Make sure you produce a clean, straight cut.
Finish the edges of your deck with edge boards or trim boards. They give the construction a finished look and conceal the cut edges of the supporting battens. Screw them on from the side or at an angle.
If you are planning steps, build them from the same material. The steps must have a tread depth of at least 30 cm and a rise of no more than 18 cm. Secure the front edges of the steps to prevent slipping.
A practical storage box for cushions, blankets or garden accessories keeps your new deck tidy. The weatherproof anthracite model complements many wood and stone colours.
Protecting and caring for your wooden deck
A wooden deck is a living material. It needs protection from the weather and UV radiation. The first treatment is the most important.
Wait until the wood has fully hardened and dried. With fresh wood, this can take several weeks. Clean the surface thoroughly to remove dust and shavings. Then apply a special decking oil or wood stain.
Work in overcast weather. The wood should not be exposed to direct sunlight. Apply the oil evenly with a brush, roller or pad. Make sure it does not pool on the surface.
Regular basic cleaning
Remove leaves and dirt regularly with a broom. This prevents damp patches and moss from forming. Give your deck a thorough clean once a year.
Use a dedicated decking cleaner and a soft-bristled brush. For stubborn dirt, a pressure washer can help. However, hold it at a shallow angle and keep it at a sufficient distance to avoid roughening the wood fibres.
After cleaning, the deck must dry completely. Only then should you apply a new protective coating if necessary. The intervals depend on the type of wood and its exposure to the weather.
Protect your patio furniture or patio heater during the damp season. A sturdy cover extends the life of your investment and keeps everything ready to use next summer.
Furnishing and enjoying your deck
Your finished deck is your personal outdoor oasis. The furnishings should be functional and comfortable. Start with the larger pieces, such as a table and chairs.
An extendable dining table, such as those you can find in our garden furniture category, offers flexibility. On sunny days, a parasol or awning provides shade.
Lighting creates atmosphere. Choose solar-powered LED lights that you can install without cables. String lights, ground spotlights or torches make the evening more inviting. For longer evenings in spring or autumn, patio heating is worth considering.
With the right plants in pots or beds along the edges, you can integrate your deck perfectly into the garden. Choose low-maintenance, hardy varieties. A visit to our garden accessories department provides inspiration for planters and climbing supports.
Your DIY wooden deck is now ready. You have not only created valuable living space, but also completed a project with your own hands. Enjoy every summer evening on it.
Frequently asked questions
- Which wood is best for a long-lasting wooden deck?
- Locally sourced woods such as larch or Douglas fir, as well as particularly hard-wearing tropical hardwoods such as bangkirai or garapa, are suitable for durable decks. WPC decking boards (wood-plastic composite) are a low-maintenance alternative with high dimensional stability and no risk of splinters. The choice depends on your budget, the look you want and how much maintenance you are prepared to do. Locally sourced woods require regular oiling, while tropical hardwoods are more expensive but last longer.
- What slope does a wooden deck need and how do I create it?
- A slope of 1-2% away from the house is essential for water drainage. Create it by laying the supports for the joists (e.g. steel bearers or point foundations) at a slight angle. Use a spirit level with a slope indicator or a string line. Calculate the height difference: for a deck length of 4 metres, a 2% slope means an 8 cm difference in height. Take this into account when planning the deck height in relation to the house threshold.
- Can I build a wooden deck directly on soil or concrete?
- You should never build directly on soil. Moisture leads to rot. A compacted gravel or chippings base with a weed membrane is the minimum requirement. A deck can be built on sound, dry concrete (e.g. an old patio slab) provided you ensure adequate ventilation beneath the boards. To do this, use special spacers or continuous joists on strip supports that allow air to circulate.
- How much space should there be between decking boards?
- A gap of 5-8 mm is standard. It allows water to drain away and gives the wood room to expand and contract as moisture levels change. Use special decking spacers or joint crosses from a specialist garden tool retailer to maintain an even gap. With very damp wood or in a shaded location, you can allow up to 10 mm of space. The gaps remain open after installation.
- When should I oil my new wooden deck for the first time?
- Treat pressure-treated wood after 4-6 weeks and locally sourced woods such as larch after 2-3 months. The wood must be completely dry and clean. With tropical hardwoods, check whether the surface still absorbs water. If it is water-repellent, no immediate treatment is needed. Use a high-quality decking oil that penetrates deeply and provides UV protection. Work in dry weather and shaded conditions.
You might also be interested in
- Wooden deck substructure: Build a stable foundation with ease
- Build a raised deck: DIY guide for your wooden deck
- Build your own patio cover: Step by step
- WPC decking boards: Benefits and care for your deck
- Laying patio tiles: Your path to a dream patio
- Paving a stone patio: Step-by-step guide for DIY enthusiasts