Cost guide
How much does decking cost?
Decking costs £60 to £110 per square metre supplied and fitted. Softwood sits at the bottom of the range, composite at the top, and a raised deck with steps and balustrade goes above it.
Typical prices
| Work | Typical UK price |
|---|---|
| Treated softwood decking, per m² | £60 to £80 |
| Composite decking, per m² | £90 to £130 |
| Hardwood decking, per m² | £110 to £170 |
| Steps, per flight | £150 to £400 |
| Balustrade, per metre | £60 to £120 |
Ask what is under the boards. Two quotes at the same price per square metre can have very different sub-frames, and the sub-frame is what fails.
What moves the price
- Board material: treated softwood, hardwood, or composite.
- Height. Ground-level decks are quick; raised decks need posts, bracing, steps and guarding.
- Ground conditions and whether the site needs levelling or clearing.
- Access. Carrying timber through a house adds time.
- Balustrade, steps and any built-in seating or planters.
What the job involves
The sub-frame is the job. Joists at 400mm centres for timber boards, or 300mm for most composite, on treated bearers with a clear gap to the ground so air moves underneath. Ground contact is what kills decks: a bearer sitting on soil holds water against the timber year round. Where the deck meets the house it must stay at least 150mm below the damp proof course, and it must not bridge the airbricks.
Questions about decking
Do I need planning permission for decking?
Usually not if it is under 300mm above ground and the total garden coverage stays within permitted development. Raised decking and balustrades over that height can need permission and can raise overlooking issues.
How long does a deck last?
Ten to fifteen years for treated softwood if the frame stays dry, twenty-five or more for hardwood and composite. The frame nearly always outlives or kills the boards.
Composite or timber?
Composite for low maintenance and stable colour; timber for lower cost and for a look that weathers. Composite needs wider expansion gaps and closer joist spacing.