Deck or Patio: Comparing Cost Over Twenty Years

Installation

Timber decking is generally cheaper to install, particularly on sloping ground where a deck can be built on posts rather than requiring the ground to be levelled and built up.

Paving requires excavation, a compacted sub-base and bedding, all of which is labour and materials before any slab is laid. On level ground the gap narrows; on a slope it widens in the deck's favour.

Composite decking sits between the two on cost, closer to paving.

Maintenance over time

Softwood decking needs cleaning and re-treating regularly — realistically every one to two years — to resist rot and weathering. Boards will need replacing periodically, and the substructure eventually.

That maintenance is either your weekend or a contractor's invoice, repeated across two decades. It is the item most often left out of the comparison.

Paving needs occasional cleaning and joint maintenance, and little else. Individual slabs can be lifted and replaced if damaged.

Composite decking needs washing and little more, which is much of its appeal.

Lifespan

Well-maintained softwood decking realistically lasts around fifteen years, less in shaded damp positions. Hardwood lasts considerably longer at higher initial cost.

Composite manufacturers typically warrant twenty-five years or more, though colour fade and surface wear occur.

Good paving on a properly built base lasts decades with minimal intervention. On the twenty-year view this is usually where the total cost comparison lands in paving's favour.

Practical differences worth weighing

Timber is warmer underfoot and more forgiving to fall on, which matters with children. It also feels different, and plenty of people simply prefer it.

Decking gets slippery when wet, particularly in shade where algae forms. Grooved boards help less than commonly believed; regular cleaning helps more. Grit-embedded strips are effective where slipping is a real concern.

Composite gets noticeably hot in strong sun, which surprises people who chose it for a south-facing terrace.

Paving in dark colours also heats up. Light-coloured porcelain stays cooler and shows less algae.

Drainage and levels, again

Both need to sit well below the damp proof course and fall away from the building. Decks need ventilation beneath them, or the substructure stays damp and fails early.

Paving needs a permeable route for water or a drainage channel. Building either up against a wall without regard to levels is the recurring expensive mistake in garden work.

Deciding

Sloping site, tight budget, want it soon: decking, ideally composite if you can stretch to it.

Level site, long-term ownership, minimal maintenance appetite: paving.