Subsidence, Drainage & Patio Longevity in Petersfield

Typical Problems We See Locally

Across the Petersfield area we regularly come across:

• Patios that have sunk or become uneven within a few years
• Driveways with dips where car wheels sit
• Water running back towards the house or garage
• Retaining walls starting to lean or bow
• Cracking around manholes or inspection chambers

Almost all of these issues come down to a combination of ground conditions and how the work was originally built, not the paving slab itself.

How Local Soil Types Affect Movement

Clay Soils (Liss / Oakhanger / Parts of Petersfield)

Clay-based soils:

• Expand when wet and shrink when dry
• Hold water, especially over winter
• Are easily disturbed during excavation works

Poorly designed patios on clay often show:

• Slabs rocking or moving individually
• Steps cracking where the ground shrinks
• Joints opening up and letting more water in

Chalk & Slopes (Steep / Buriton / South Downs)

Chalk and flinty slopes are generally firm, but:

• Water can travel quickly beneath hard surfaces
• Steep gradients increase the risk of slip or creep
• Thin soil over chalk can wash away if not protected

On these plots, poor detailing often leads to:

• Patios gradually sliding down-slope
• Edge restraints failing
• Retaining walls being pushed by water and soil pressure

Mixed / Made Ground (Central Petersfield / Extensions)

Older infill plots and extended gardens often sit on “made ground” — a mixture of soil, rubble and historic spoil.

Without selective excavation and proper sub-bases, this can cause:

• Localised dips where soft spots weren’t removed
• Cracking around old foundation lines or services
• Random movement in different parts of the same patio

Drainage: The Biggest Factor in Patio Longevity

Good drainage protects both your paving and your house. In and around Petersfield we focus on three main aspects:

1. Falls & Levels

Hard surfaces should be laid with a gentle, controlled fall:

• Away from the house or any building
• Towards lawns, beds or drainage channels
• Across the shortest sensible distance

Minor level mistakes can send water towards thresholds or cause permanent puddles.

2. Where the Water Goes

For most patios and driveways we look at:

• Permeable build-ups where appropriate
• Soakaways or crate systems (subject to soil type)
• Channel drains at key pinch points (doors, garages)
• French drains at the base of banks or walls

In heavy clay areas (Liss, parts of Petersfield) soakaway design needs extra thought, as water may not percolate quickly.

3. Keeping Water Away from Buildings

One of the biggest long-term risks is water sitting against:

• House walls
• Garage brickwork
• Retaining walls and steps

Over time this can increase damp problems and undermine foundations, especially where older footings are shallow.

Tree Roots, Shrubs & Nearby Structures

In some Petersfield streets and villages, tree roots and large shrubs are a major factor in ground movement.

Clay + Trees = Extra Movement

On clay soils, thirsty trees and hedges can:

• Draw moisture out of the ground in summer
• Increase seasonal shrink–swell cycles
• Cause cracking in hard surfaces and small walls

Roots & Physical Displacement

Even on non-clay soils, roots can physically lift or distort:

• Patios laid too close to trunks
• Old paths with negligible sub-bases
• Lightweight garden walls with shallow strip footings

Part of our survey is to look at established trees and shrubs near any new hard landscaping, so we can design around them.

Designing for Longevity in Petersfield

To build patios and driveways that last across Petersfield’s varied ground conditions, we focus on:

• Correct excavation depth for your soil type
• Appropriate sub-base material (Type 1 vs Type 3)
• Compaction in controlled layers, not just once at the end
• Thoughtful drainage, especially near properties
• Strong edge restraints to prevent creep and spread

Extra Measures on Higher-Risk Plots

On steep slopes or problematic clay we may also suggest:

• Geogrids beneath sub-bases on driveways
• Stepped foundations on inclined sites
• Weep holes and drainage layers behind retaining walls
• Breaking large areas into smaller, controlled sections

When to Worry About Subsidence

Localised movement in a patio is annoying but not always a sign of wider structural problems. You may wish to seek professional structural or insurance advice if you notice:

• Cracks in the house itself (walls, ceilings, door frames) that are widening
• Doors or windows sticking in more than one area of the property
• Significant, ongoing movement near foundations or main walls

For isolated garden features like patios, paths or small walls, we can normally diagnose the likely cause on site and recommend either repair or rebuild options.

Maintenance Tips to Extend Patio Life

• Keep joints in good condition to reduce water ingress
• Clear leaves and debris from channels and drains
• Avoid heavy plant pots sitting permanently on weak corners
• Monitor any small cracks or dips rather than ignoring them

Early intervention often turns a major rebuild into a smaller repair.

Areas We Cover

Petersfield · Sheet · Steep · Buriton · Liss · Rogate · Langrish · Froxfield · East Meon · West Harting · South Harting · South Downs villages

Concerned About a Sinking Patio or Cracking Wall?

If you’ve noticed movement, poor drainage or recurring puddles, we can visit, assess the ground conditions and suggest practical options to put things right and keep them stable long term.

Book a Subsidence & Drainage Assessment

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