How to build stairs from composite decking boards? | Step-by-step installation guide.

Why build steps from composite decking boards?

Before we move on to the installation itself, it is worth considering why composite decking boards are the best material for terrace or garden steps.

• Durability and resistance – they do not absorb moisture or rot, and are resistant to mould and insects.

• Safety – they have an anti-slip surface (grooved), which is useful in the rain or in winter.

• Easy maintenance – they do not need painting or treatment with preservative, and water is all you need to clean them.

• Appearance – they imitate wood and are available in a range of colours, allowing you to match them to your terrace or façade.

• Eco-friendly – many models are made from recyclable materials.

It is no surprise, then, that more and more people search for: “how to build steps from composite decking boards” and plan this kind of project in their own garden.

Step 1: Planning and designing the steps.

Every installation starts with a good design. Consider:

• How many steps should there be?

• What width and height would be comfortable?

• Will they lead to a terrace, balcony or directly into the garden?

Remember that the optimum step height is 15–17 cm, and its width should be 28–30 cm. This will make the steps comfortable and safe.

It is also worth taking the slope of the ground into account and planning a stable base – ideally a concrete slab, foundation blocks or a steel structure, to which you will attach the joists and decking boards.

Step 2: Preparing the base and structure.

For steps made from composite decking boards to be durable, they must not be installed directly on the ground. The base must be stable and resistant to subsidence.

• For a wooden or concrete terrace, the step structure can rest directly on the existing base.

• On the ground, concrete blocks are the best option, with composite or aluminium joists installed on top.

Also remember to allow for an adequate slope (approx. 1–2%) so that water can drain freely instead of collecting on the steps.

Step 3: Installing the joists.

The joists are the foundation of the entire structure – the stability of the steps depends on them.

• Lay them parallel, at intervals of 30–40 cm.

• In areas subject to heavy loads (e.g. the edges of the steps), it is worth spacing them more closely.

• The joists must be securely fixed to the base, preferably using anchors and screws.

• Remember to use spacers to ensure ventilation.

This will make the structure sturdy and resistant to moisture.

Step 4: Installing composite decking boards on the steps.

Once the joists are in place, you can move on to installing the composite decking boards themselves.

• Always start at the edge of the step. Fit the front board first, followed by the horizontal (tread) board.

• Fix the boards using fixing clips, which ensure an even expansion gap and concealed fixings.

• Leave gaps by the walls and along the side of the structure (approx. 5 mm) so the boards have room to move as the temperature changes.

• If the steps are wide, consider using solid boards – they are heavier but more durable.

Thanks to their grooved surface, the steps will be non-slip and safe even in the rain.

Step 5: Finishing and appearance.

Terrace steps should be not only functional, but elegant too.

• Fit cover strips along the sides to conceal the joists and structural components.

• Match the colour of the boards to the terrace or building façade – you can choose from honey, grey, graphite or chocolate shades.

• If you wish, fit additional LED lighting on the steps – it is not only practical, but also an attractive solution.

The most common mistakes when building steps from composite decking boards.

• Inadequate base – the steps may settle and become crooked.
• Installation without expansion gaps – this can cause bulging on hot days.
• Joists spaced too far apart – the boards may bend and break.
• No cover strips – the steps will look unattractive and “unfinished”.

Avoid these mistakes and you will have a structure that lasts for years.

FAQ – Frequently asked questions.

Can you build steps from composite decking boards yourself?
Yes, it is possible with basic DIY skills and the right tools.

Are composite decking boards safe on steps in winter?
Yes, their grooved surface makes them non-slip. You can also spread salt or sand on them.

How do you care for steps made from composite decking boards?
Regular cleaning with water or a pressure washer is all that is needed – no painting or treatment required.

Can composite decking boards be combined with concrete or wood?
Of course, the boards work very well with other materials, and such combinations are often used.