Composite or timber decking: what to choose and when you need permission

Decking is a good way to create a level outdoor space on a sloping garden or step straight out from the house. The two main choices are timber and composite.

Timber decking

• Softwood is the most affordable option, but needs regular treatment to stay sound.

• Hardwoods such as balau or ipe are dense, durable and beautiful, and weather to a silver grey if left untreated.

• Natural timber can become slippery in shade, so grooved boards and regular cleaning help.

Composite decking

• Made from a mix of wood fibres and plastic, so it does not rot, splinter or need staining.

• Colour stays more consistent over time.

• It can get hot in direct sun and usually costs more upfront.

• Quality varies a lot between brands, so look at warranties and fire ratings.

The 30cm rule

Under permitted development for houses in England, decking or any other raised platform more than 30cm above the ground needs planning permission. Together with other outbuildings and extensions, decking also must not cover more than half the garden. Listed buildings and conservation areas can have extra restrictions.

Building decking that lasts

• A solid, level frame on proper footings matters more than the boards.

• Leave ventilation and drainage underneath to stop the frame rotting.

• Use stainless steel or hidden fixings for a clean finish.

• Plan steps, lighting and edging at the same time.

Planning a deck or new garden?

Koniu Construction designs and builds decking, patios and gardens across South West London and Surrey. Get in touch to talk through your garden.