Natural Pool Construction Materials: Complete UK Guide

Choosing the Right Materials

The materials you choose for your natural swimming pool affect its appearance, longevity, maintenance, and environmental impact. This guide covers everything from waterproof membranes to the gravel in your regeneration zone.

Waterproof Liners

The liner is your pool's foundation—it prevents water loss and protects groundwater.

EPDM Rubber

The industry standard for natural pools EPDM (Ethylene Propylene Diene Monomer) is our preferred choice:

• Lifespan: 30-50 years
• Flexibility: Conforms to complex shapes
• UV resistance: Excellent
• Puncture resistance: Good (1mm+ thickness recommended)
• Eco credentials: Recyclable, fish and plant safe
• Cost: £15-25/m²

Pros:

• Proven track record in UK climate
• Stretches without tearing
• Easy to repair if punctured
• Root-resistant

Cons:

• Visible seams on large installations
• Black colour (though often covered)

Butyl Rubber

Traditional alternative

• Similar properties to EPDM
• Slightly more expensive
• Excellent longevity
• Less commonly available now

PVC Liners

Budget option

• Lifespan: 10-20 years
• Cost: £8-15/m²
• Less flexible than EPDM
• Plasticisers can leach over time
• Not recommended for premium installations

Bentonite Clay

Natural waterproofing

• Applied as sodium bentonite blanket
• Swells when wet to create seal
• Completely natural material
• Requires specific soil conditions
• Higher skill needed for installation
• Can be combined with liner as backup

Concrete/Gunite

For formal designs

• Requires waterproof coating (pool paint or membrane)
• Allows precise geometric shapes
• Higher construction cost
• Possible cracking in UK freeze-thaw cycles
• Less common for natural pools

Underlayment Protection

Whatever liner you choose, protect it:

• Geotextile fleece: 300-500gsm minimum
• Sand bed: 50-100mm compacted sand
• Purpose: Prevents punctures from stones, roots, burrowing animals

Never skip the underlayment—it's cheap insurance for your expensive liner.

Edging Materials

The edge treatment defines your pool's character.

Natural Stone

Premium choice for natural pools

• Yorkstone, sandstone, limestone
• Sourced from UK quarries
• Every piece unique
• Excellent durability
• Cost: £100-300/m²

Laying methods:

• Cantilevered over water (contemporary look)
• Flush with water (naturalistic)
• Beach-style gradual entry

Timber Decking

Warm, inviting edges

• Hardwood (oak, iroko) for longevity
• Softwood (treated larch, cedar) more affordable
• Creates seating and sunbathing areas
• Requires periodic maintenance
• Cost: £80-200/m² installed

Composite Decking

Lower maintenance alternative

• Wood-plastic composite materials
• Won't rot or splinter
• Less natural appearance
• Good 25-year warranties
• Cost: £100-180/m² installed

Pebble & Gravel Beaches

Perfect for natural aesthetic

• Gradual entry into water
• Wildlife-friendly
• Easy on feet
• Requires edging to contain
• Cost: £30-80/m²

Grass Edges

Maximum integration

• Pool merges with garden
• Reinforced grass edge systems available
• Lowest cost option
• Requires careful drainage design

Regeneration Zone Substrates

The planting zone needs specific materials for biological filtration.

Gravel (Essential)

The biological engine

• Size: 8-16mm washed gravel ideal
• Depth: 200-400mm
• Material: Rounded river gravel, not sharp aggregate
• Provides surface area for beneficial bacteria
• Anchors plant roots
• Cost: £40-60/tonne delivered

Planting Substrate

For emergent plants

• Low-nutrient aquatic compost
• Mixed with gravel 30/70
• Placed in planting pockets
• Never use garden soil (too nutrient-rich)

Base Layer

Drainage and support

• 20-40mm gravel below planting substrate
• Ensures water circulation
• Prevents anaerobic zones

Pump & Circulation Equipment

Moving water through the regeneration zone is critical—the nitrogen cycle depends on it.

Circulation Pumps

• Flow rate: Calculate based on pool volume
• Energy efficiency: Look for A-rated pumps
• Reliability: Quality brands (Oase, Messner, AquaMax)
• Running 24/7 typically
• Typical cost: £300-1,500

Skimmers

• Surface debris removal
• Floating or built-in options
• Essential for leaf management
• Cost: £150-500

Bottom Drains (Optional)

• Remove settled debris
• Connect to filtration
• Better water clarity
• Higher installation complexity

Filtration Options

Gravity-Fed Systems

Simple, reliable, low-energy:

• Water flows by gravity through planted filters
• No mechanical filters to maintain
• Larger footprint needed
• Lower running costs

Pump-Fed Systems

More compact, controlled:

• Pressurised flow through filters
• Can include UV clarifiers
• Smaller regeneration zone possible
• Higher energy consumption

See our filtration systems comparison for detailed analysis.

UK Climate Considerations

Frost Resistance

All materials must handle UK winters:

• Stone: Ensure frost-proof rating
• Timber: Heartwood grades only
• Equipment: Winterisation or frost-proof models

UV Stability

Summer sun degrades some materials:

• EPDM: Excellent UV resistance
• PVC: Check UV stabiliser content
• Composite decking: Varies by manufacturer

Rainfall & Drainage

UK's wet climate requires:

• Overflow systems for heavy rain
• Drainage away from pool edges
• Permeable paving where possible

Sustainability Considerations

Natural pools should use sustainable materials:

Low Impact Choices

• Locally sourced stone (reduces transport)
• UK-grown timber (FSC certified)
• Recycled composite materials
• EPDM (recyclable, long-lasting)

Materials to Avoid

• Imported tropical hardwoods (unless FSC)
• Cheap PVC liners (short lifespan = waste)
• Non-recycled plastics

Cost Summary by Category

| Material Category | Budget Option | Premium Option | |------------------|---------------|----------------| | Liner (per m²) | PVC £10 | EPDM £25 | | Edging (per m²) | Gravel beach £40 | Yorkstone £300 | | Decking (per m²) | Softwood £80 | Hardwood £200 | | Pump system | Basic £400 | Premium £1,500 | | Gravel substrate (tonne) | Standard £40 | Washed round £60 |

Quality Matters

Avoid the common mistakes of cutting costs on critical materials. A £10/m² liner saving means nothing if it fails in 10 years instead of 40.

Ready to discuss materials for your natural pool? Our design consultation includes material recommendations tailored to your garden and budget.