Composite vs timber decking: an honest comparison

What each material is

Timber decking is usually pressure treated softwood, grooved or smooth, though hardwoods are also available. Composite decking is made from a mix of wood fibre or flour and plastic, moulded into boards. Some composite boards are solid; others are hollow with internal chambers. Better quality composite boards have a capped outer layer that resists staining and fading.

Looks

Timber looks and feels like wood because it is wood. When new, softwood has a pale green or brown tone from the treatment, and over time it weathers to silver grey unless it is stained. Some people love that change; others do not. Composite boards come in fixed colours and grain patterns that stay much the same for years. The best ones look convincing, but up close most people can still tell the difference.

Maintenance

This is the clearest difference. A timber deck needs a clean every year and a fresh coat of preserver, oil or stain every year or two to keep it looking good and resisting the weather. Splits and raised grain need sanding occasionally. Composite needs a wash with soapy water and a soft brush, and that is about it. It does not need staining or sealing. If you know you will not keep up with treatment, composite is the more forgiving choice.

Grip in wet weather

Any deck can be slippery in a shaded, damp corner where algae grows. Grooved timber boards help a little but are not a cure, and the grooves can hold dirt. Composite boards are generally less prone to algae because they absorb less water, and many have textured surfaces for grip. Whichever you choose, keeping the deck clean and letting air move under it makes the biggest difference.

Lifespan and movement

A well built treated softwood deck can last many years if it is maintained and the boards are kept off the ground. Neglected timber rots sooner, especially where boards sit in damp shade. Composite boards do not rot, splinter or crack in the same way, and they usually come with a manufacturer's warranty, the terms of which vary between brands. Composite does expand and contract with temperature, so the spacing and fixing method the manufacturer sets out must be followed.

Heat underfoot

In full summer sun, dark composite boards can get noticeably hot under bare feet, more than timber. Lighter colours help. If your deck faces south and children will run about on it barefoot, it is worth bearing in mind when choosing a colour.

The frame underneath

Whichever boards go on top, the deck is only as good as its frame. Joists, bearers and posts are usually treated timber in both cases, sitting on solid footings with ground cover membrane underneath to stop weeds. Composite boards often need joists set closer together than timber, which adds to the frame. A good frame, level and properly spaced, is what stops a deck bouncing, sagging or rocking whatever the boards are made of.

Which suits your garden?

• Choose timber if you want a natural wood look, like a deck that weathers, and do not mind a yearly treatment
• Choose timber for a small or temporary deck where the lower material price matters most
• Choose composite if you want low upkeep and a consistent colour for years
• Choose composite for shaded, damp spots where timber would struggle
• Choose a lighter colour of either for a deck in full sun

Need it sorted? Book decking installation

Both timber and composite decks are built for small and medium gardens around Rochester and Medway. See decking installation for how a deck is built, then send photos and rough measurements through the quote form.

Frequently asked questions

Landscaping