Chichester Soil Types & Build Considerations

Main Soil Types Across Chichester

1. Chalk Soils (North Chichester, Lavant, Goodwood)

Chalk drains extremely well, making it ideal for soakaways and sub-base stability. However, chalk can collapse if over-excavated into cavities or left with unsupported faces.

On steeper chalk slopes above Chichester, we often combine a well-compacted Type 1 sub-base with careful falls away from buildings and, if needed, slot drains or soakaways sized to local rainfall.

2. Coastal Sandy Soils (Bosham, Fishbourne, Apuldram)

These soils drain well but shift easily without:

• geotextile separation membranes to stop sub-base sinking into the sand
• proper compaction in thin layers
• Type 1 or Type 3 reinforcement to lock everything together

For porcelain and sandstone patios on coastal sands, getting the build-up right is the difference between a stable terrace and one that ripples or dips over time.

3. Clay Soils (Tangmere, Oving, North-East Chichester)

Clay expands when wet and shrinks when dry — a major cause of movement in patios, driveways and retaining walls.

Best practice includes:

• Type 3 sub-base to improve drainage through the build-up
• Soakaways with crate systems to hold and release roof or patio water
• French drains for surface control along boundaries and at the base of walls
• Geogrid reinforcement for unstable or made-up areas

Around Tangmere and Oving this often means digging a little deeper, removing soft subsoil and rebuilding with engineered layers designed for movement and wet winters.

4. Mixed / Disturbed Ground (Modern Estates)

Developer backfill soils can be a cocktail of rubble, clay, sand and buried turf. They usually require deeper excavation and stabilisation before we even think about laying paving or building a wall.

On newer Chichester estates we frequently encounter this kind of disturbed ground when lifting old, sinking terraces or failed garden makeovers.

How Soil Type Affects Landscaping Work

Patios

• Chalk: excellent for stability, but falls must be precise to avoid water tracking along the surface
• Sand: use geogrid + membrane to prevent movement and rutting
• Clay: use Type 3 + drainage and consider flexible jointing on larger areas

Whether you choose porcelain or natural stone, the soil beneath is just as important as the slab on top. Our patio installation guide for Chichester explains how we adapt build-ups to each soil type.

Driveways

• Gravel works beautifully on chalk and sand with the right edging and sub-base
• Resin-bound surfaces require particularly strong sub-bases on clay
• Block paving needs careful compaction in sandy areas to avoid settlement

On heavy clay, it’s common to combine a free-draining sub-base with channels or soakaways, and to check that any new hard surfacing complies with local planning and drainage rules.

Retaining Walls

• Clay zones: require advanced drainage behind the wall and carefully designed footings
• Chalk slopes: may need reinforcement and stepped terracing
• Sandy ground: RSJs or deeper footings are often recommended

Our retaining wall rules & safety guide covers when you might need engineering input around Chichester’s trickier plots.

Drainage Installations

• Chalk → soakaways highly effective
• Sand → great drainage but unstable without separation
• Clay → French drains and managed discharge are often essential

For more detail on surface water control, see our Chichester garden drainage & groundworks guide.

Soil Characteristics by Area

• Bosham: High water table + coastal sand
• Fishbourne: Coastal sand, some silt
• Lavant: Chalk + shallow gradients
• Goodwood: Chalk slopes
• Tangmere: Heavy clay
• Oving: Mixed clay & subsoil
• Donnington / Hunston: Low-lying silt & clay
• Westhampnett: Mixed ground influenced by nearby infrastructure

Why Soil Knowledge Matters

Many long-term landscaping problems — sinking patios, collapsing walls, standing water, shifting driveways — are caused by building the wrong structure on the wrong soil.

By understanding your ground conditions up front, we can design patios, driveways and foundations that resist subsidence and cope better with Chichester’s wet winters and dry spells.

FAQ: Chichester Soils & Landscaping

Is Chichester mostly clay or chalk?

Neither — it’s a genuine mix. North of the city (Lavant, Goodwood) is predominantly chalk, the coastal fringe around Bosham and Fishbourne is sandy, and areas like Tangmere and Oving sit on heavier clay. That’s why two gardens only a few miles apart can need very different construction details.

Do I always need a soakaway for new patios and driveways?

Not always, but new impermeable surfacing often needs either permeable construction or a managed discharge point. On chalk, a soakaway can work brilliantly; on clay, we may look at French drains, channel drains or permeable build-ups instead. We’ll advise on options during your site visit.

Will soil type affect planning or Building Regulations?

Soil type itself doesn’t trigger planning, but it influences how we comply with surface water rules and how we design any structural elements. Larger retaining walls or significant level changes may need extra engineering, especially on clay slopes or made-up ground.

Can you assess my soil on a visit?

Yes. As part of a typical quotation visit we’ll look at your soil type, drainage routes, existing structures and planting, then explain how that feeds into the design and build-up.

Areas We Cover

Chichester · Fishbourne · Bosham · Lavant · Tangmere · Oving · Donnington · Hunston · Apuldram · Westhampnett · Goodwood · South Downs villages

Need Expert Advice on Your Soil Type?

We carry out soil assessments and design construction plans matched to your garden's ground conditions, whether you’re planning a single terrace or a full garden rebuild.

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