Decking Ideas UK: A Practical Guide to Garden Decking

Decking is the most useful single surface in a UK garden. It creates an outdoor room, solves the problem of an awkward slope, and turns an unusable corner into a real living space. Done well, a deck will be in use from March to November. Done badly, it will be slippery, rotten, and out of fashion within 10 years. This guide is a UK-specific walkthrough of the materials, layouts, costs and planning rules that make a deck work.

The principle of UK decking
Timber vs composite
The main board types
Subframe and foundations
Layouts that work
Multi-level and split-level
Railings and balustrades
Deck lighting
UK planning rules
DIY vs professional
UK cost guide
Alternatives to decking
Common mistakes
Decking FAQs
Final thoughts

The principle of UK decking

A UK deck is a raised platform, usually timber or composite, that creates a level surface in a garden that is otherwise uneven or unusable. The right answer for a sloping garden, a garden with poor soil, or a garden that needs an outdoor room.

The key decision is the material. Timber is the traditional choice; composite is the modern choice. Each has its place.

Timber vs composite

Timber (the traditional choice)

Softwood (pressure-treated pine) or hardwood (oak, balau, iroko). The right answer for a period home or a country garden. Timber is warm, beautiful, and ages well, but it needs cleaning and re-coating every 2 to 3 years.

Softwood (pine). The cheapest option. Pressure-treated for ground contact, with a 15-year guarantee against rot. From Timber Focus or Jacksons. £40 to £80 per m² supply only.
Hardwood (oak, balau). The most hard-wearing and most beautiful. Lasts 25+ years with minimal maintenance. From Tuin or Silva Timber. £80 to £150 per m² supply only.

Composite (the modern choice)

A blend of recycled wood fibre and recycled plastic, formed into boards that look like timber. The right answer for a low maintenance UK garden. Composite is hard-wearing, easy to clean, and never needs painting or staining, but it looks more uniform than timber and can get hot in direct sun.

From Trex, Ecoscape or Cladco. £60 to £120 per m² supply only.

For most UK homes, composite is the right answer. It is hard-wearing, low maintenance, and lasts 25+ years. The price has come down significantly in the last 5 years, and the quality has gone up. The main downside is the look, which is more uniform than real timber; for a period home, real timber is the right answer.

The main board types

Three main board profiles.

Solid timber board. A solid piece of timber, 20mm to 30mm thick, with a smooth or grooved face. The traditional choice. Susceptible to warping and cupping over time.
Hollow composite board. A hollow composite board, lighter and cheaper than solid composite. Less strong than solid, can be noisy underfoot.
Solid composite board. A solid composite board, heavier and more expensive than hollow composite. More like timber underfoot, less likely to sag.

For most UK homes, solid composite or solid timber is the right answer. Hollow composite is acceptable for a small, low-traffic deck (under 15m²), but it can flex and sag over time.

Subframe and foundations

The subframe is the part of the deck that does not get seen, but it is what determines whether the deck lasts 5 years or 25.

The right subframe for a UK deck.

Posts. 100mm x 100mm pressure-treated softwood posts, set in concrete pads at 1.5m to 2m centres. The most stable option.
Bearers. 45mm x 145mm pressure-treated softwood bearers, fixed to the posts with galvanised joist hangers. The most common option.
Joists. 45mm x 95mm pressure-treated softwood joists, fixed to the bearers at 400mm to 600mm centres. The standard option for a domestic deck.
Boards. The deck boards, fixed to the joists with stainless steel or coated deck screws.

For a raised deck (over 600mm above the ground), the subframe must be designed by a structural engineer or a CIAT architect. The posts, bearers and joists must be sized for the span, the load, and the wind exposure. The TRADA publishes a free guide to domestic deck construction.

Layouts that work

Three layouts cover most UK decks.

Rectangular, against the house

The simplest and most common. A rectangular deck, attached to the back of the house, running the full width of the patio doors. The right answer for most UK homes. 4m x 4m is a useful minimum; 5m x 6m is comfortable.

L-shape (wraparound)

An L-shaped deck that wraps around a corner of the house, creating two distinct zones (a dining area and a lounge area, for example). The right answer for a UK home with a corner patio or a garden room.

Freestanding

A deck that is not attached to the house, often in a corner of the garden, used as a feature platform for a hot tub, a dining area, or a sun lounger. The right answer for a large garden or a garden that needs a destination.

Multi-level and split-level

For a sloping UK garden, a multi-level or split-level deck is the most useful design. The deck steps down the slope, creating two or three distinct zones, each with its own view of the garden.

The right answer for a split-level deck.

Plan the levels in advance. A 30cm to 50cm step is enough to define a level; a 60cm+ step needs a handrail.
Use the same material throughout. A multi-level deck in three materials looks busy; the same deck in one material looks designed.
Add a planter or a step at the change of level, to define the change and to provide a place for a focal plant.

Railings and balustrades

For a raised deck (over 600mm above the ground), a handrail is required by building regulations. The minimum height is 900mm for a deck up to 600mm above the ground, and 1.1m for a higher deck.

Three main options.

Timber balustrade. The traditional choice. Softwood or hardwood posts, top and bottom rails, with vertical balusters. £80 to £150 per linear metre.
Stainless steel cable. A modern option, with timber posts and horizontal stainless steel cables. £150 to £300 per linear metre.
Glass panel. The most modern option, with frameless or semi-frameless glass panels. £300 to £600 per linear metre. The right answer for a view that must not be blocked.

Deck lighting

The right lighting turns a deck into a year-round space. The most useful options.

Recessed deck lights. Small LED lights, recessed into the deck boards, lighting the steps or the perimeter. From Lighting Direct or Collingwood. £20 to £50 per light.
Post cap lights. LED lights fitted to the top of the railing posts, providing soft general lighting. From Lighting Direct or Astro Lighting. £30 to £80 per post.
Step lights. LED strip lights under the lip of each step, lighting the change of level. From LED Hut or Philips Hue. £100 to £400 per step.

All outdoor lighting should be IP65-rated or higher. The Electrical Safety First publishes a free guide to outdoor electrical safety.

UK planning rules

In most cases, a UK deck does not need planning permission if it is at the rear of the house, is no more than 30cm above the ground, and covers less than 50 per cent of the garden.

For a raised deck (over 30cm above the ground), or one that covers more than 50 per cent of the garden, or one that is in front of the principal elevation, planning permission is required. For a deck within 2m of a highway, the height limit is 30cm.

For a listed building or a conservation area, the rules are tighter. Check with your local authority before building. The Planning Portal publishes a free guide.

DIY vs professional

A ground-level rectangular deck is a realistic DIY project for a competent homeowner. The work is well within the scope of someone with basic carpentry skills and a weekend to spare.

For a 4m x 4m ground-level deck.

DIY: £1,200 to £2,500 in materials, 2 to 3 weekends of work
Professional installation (supply and fit): £3,000 to £6,000, fitted in 3 to 5 days

For a raised deck, a multi-level deck, or a deck with railings, professional installation is strongly recommended. The subframe needs to be designed by a structural engineer, and the safety implications of a raised deck are significant.

UK cost guide

Typical UK decking costs in 2025 prices, per m².

Softwood timber, supply only: £40 to £80
Hardwood timber, supply only: £80 to £150
Hollow composite, supply only: £50 to £90
Solid composite, supply only: £60 to £120
Subframe (posts, bearers, joists), supply only: £20 to £40
Timber balustrade, supply and fit: £80 to £150 per linear metre
Glass balustrade, supply and fit: £300 to £600 per linear metre
Recessed deck lights, supply and fit: £30 to £80 per light
Professional installation (labour only): £50 to £100 per m²

A full 20m² deck with subframe, boards, balustrade and lighting typically lands at £2,500 to £5,000 for a softwood or hollow composite deck, or £4,000 to £8,000 for a hardwood or solid composite deck.

Alternatives to decking

For some UK gardens, decking is not the right answer. The most useful alternatives.

Porcelain or sandstone paving. The most hard-wearing option. No maintenance beyond an annual wash. The right answer for a low maintenance garden.
Resin-bound gravel. A smooth, porous surface that looks like gravel but behaves like paving. The right answer for a contemporary garden.
Self-binding gravel. A gravel that binds together, holds a shape, and is comfortable to walk on. The right answer for a country garden.

For most UK homes, paving is the right answer for a low maintenance garden, and decking is the right answer for a garden that needs an outdoor room. The two can be combined: a paved patio at the back of the house, with a deck at the end of the garden.

Common mistakes

Cheap timber. Untreated softwood will rot within 5 years. Use pressure-treated softwood, cedar, larch, or oak.
No subframe ventilation. A deck that is sealed to the ground will trap moisture and rot within 10 years. Leave a 50mm gap between the boards and the ground, or use a raised subframe.
Wrong fixings. Use stainless steel or coated deck screws, not standard woodscrews. Standard woodscrews will rust and stain the timber within 2 years.
No fall. A flat deck will pool water. Build in a 1:80 fall (1cm per 80cm) so the water runs off.
No maintenance. Timber needs cleaning and re-coating every 2 to 3 years. Composite needs an annual wash. Skip the maintenance and the deck will fail within 10 years.

Frequently Asked Questions

1. Do I need planning permission for decking in the UK?

In most cases, no, if the deck is at the rear of the house, no more than 30cm above the ground, and covers less than 50 per cent of the garden. For a raised deck, or one that covers more than 50 per cent, planning permission is required. For a listed building or conservation area, the rules are tighter. Check the Planning Portal before building.

2. What is the best material for UK decking?

For most UK homes, composite. It is hard-wearing, low maintenance, and lasts 25+ years. For a period home or a country garden, hardwood (oak or balau). For a tight budget, pressure-treated softwood.

3. How much does decking cost per m² in the UK?

For a softwood deck, supply and fit, £80 to £150 per m². For a hardwood deck, £150 to £300 per m². For a solid composite deck, £120 to £250 per m². Add £80 to £150 per linear metre for a timber balustrade, or £300 to £600 per linear metre for a glass balustrade.

4. How long does a UK deck last?

Softwood: 10 to 15 years with maintenance. Hardwood: 25+ years with minimal maintenance. Composite: 25+ years with minimal maintenance. The subframe is usually the first thing to fail, so pressure-treated softwood posts and bearers are essential, even under a composite deck.

5. Is composite decking slippery when wet?

Modern composite decking has a textured or grooved face that is not slippery when wet. Avoid smooth composite, which can be slippery. For a UK garden, a board with a deep wood-grain texture is the safest option. From Trex, Ecoscape or Cladco.

6. Can I put decking straight onto soil?

No. A deck on soil will rot within 5 years. The subframe must be on concrete pads, on screw piles, or on a hard standing. The boards must be raised off the soil to allow air circulation.

Final thoughts on decking

A UK deck is one of the most useful additions a garden can have. Choose the right material, the right subframe, and the right maintenance, and the deck will be in use from March to November. Avoid cheap timber, flat layouts, and no-maintenance thinking, and the deck will pay for itself within 5 years.

For more on the wider project, see our guides to pergola ideas UK and outdoor kitchen ideas UK.

Table of contents

The principle of UK decking