Describe your cracks

Underpinning guide

Underpinning in Hampshire: what it involves

Find out what mass concrete, beam and base, and piled underpinning actually mean for your home. Learn how a specialist decides which method suits the ground beneath you, and why digging is not always the only answer.

Subsidence help

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Foundation methods

How specialists underpin a house in Hampshire

A picturesque aerial view of terraced houses amidst lush greenery in a Welsh valley.
Mass concrete underpinning
The mass concrete underpinning method involves digging short sections below the existing footing and filling them with concrete in sequence, so the wall stays supported while the foundation is deepened.
Beam and base repair
A beam and base foundation repair uses a reinforced concrete beam built below the current footings. The beam transfers the load of the wall onto new concrete bases placed at intervals.
Piled underpinning
Piled underpinning for subsidence drives or drills steel or concrete piles through weak soil down to a firm stratum. A reinforced beam then links the piles together to carry the wall.
Resin injection
Where the ground allows, resin injection strengthens the soil beneath shallow foundations without excavation. This avoids the disruption of traditional digging and suits certain clay conditions.
Screw piling
On made ground or soft coastal land, screw piling provides support by winding steel shafts into stable layers. It works where driven piles would cause too much vibration.

What to expect if your home needs work

People often wonder whether they must move out, how much garden will be lost and who pays. Here is what usually happens when foundations need attention.

  • Living at home during the work Most houses remain habitable while underpinning takes place. The specialist works on one section at a time, keeping the structure stable. You may need to keep clear of specific rooms or external doors.
  • Garden and driveway access Excavation happens against the affected walls, so flower beds and paths near those faces will be dug up. Driveways are broken out only if the foundation line runs directly beneath them.
  • Timescale from dig to backfill The underpinning cost and timescale depend on the scheme length. Mass concrete bays take days each to cure before the next opens. A typical single wall might take two to four weeks from first dig to final backfill.
  • Insurance and clay shrinkage If cracking stems from clay shrinkage or tree root moisture loss, buildings insurance often covers the stabilisation. The insurer usually appoints a loss adjuster to agree the scope before any contractor starts digging.
  • Selling or remortgaging later Having part of a house underpinned does appear on future surveys. Lenders and buyers ask for the specification and completion certificate. Properly documented work rarely prevents a sale, but missing paperwork causes delays.
  • Partial versus full schemes Only the affected corner or wall usually requires attention. Deepening foundations in clay soil beneath a single bay is common practice. The specialist calculates how far the movement extends and stops there.
Three construction vehicles parked in a field

What happens after you send an enquiry

You describe what you have noticed. The rest follows a set sequence of inspections and decisions made by the specialist, with very little required from you beyond granting access.

  1. As soon as you send it

    Your details are received

    The information you provide about the cracks, the location and the type of home goes to a specialist covering your part of Hampshire.

  2. Once the specialist has

    A site inspection is arranged

    The specialist visits to examine the walls, measure crack widths and look at the ground conditions around the foundations. You just need to be home to let them in.

  3. After the inspection

    Monitoring or testing begins

    If the movement is still active, the specialist may fit tell-tales across cracks or request trial holes to see the footing depth. This determines whether do i need my house underpinned is the right question.

  4. Once data is gathered

    A scheme is specified

    The specialist writes a report recommending either monitoring, resin injection or a particular underpinning method. You receive this before any quotes for physical work are prepared.

Checks a specialist makes before specifying work

A specialist does not guess at the cause. They follow a fixed order of checks because treating the symptom without finding the trigger leads to repeated damage.

  1. Crack pattern and width

    The specialist maps every visible crack, noting whether it tapers, runs diagonally or follows mortar joints. This separates thermal movement from foundation settlement.

  2. Drainage and water escape

    A CCTV camera or dye test rules out leaking drains washing soil away beneath the footings. Broken pipes cause localised voids that mimic deeper subsidence.

  3. Tree proximity and species

    Roots from certain trees extract large volumes of moisture from clay. The specialist measures distances and identifies species to assess whether vegetation is driving seasonal movement.

  4. Trial holes and soil sampling

    Small excavations expose the existing footing depth and the soil profile beneath it. Samples confirm whether the ground is clay, chalk, gravel or fill.

  5. Level survey

    Precise measurements along the damp proof course show how far the wall has dropped relative to the rest of the building, confirming the extent of movement.

If drainage leaks and tree roots both appear present, the specialist addresses the leak first and monitors before blaming vegetation.

Recognising what you are seeing at home

The point is not to diagnose the problem yourself. Only a physical inspection settles what is happening beneath the floor. What matters now is judging how quickly to ask for that inspection, based on what you can already see.

  • A diagonal crack wider than 3mm opening near a window or door cornerToday

    This suggests differential movement where one section of footing has dropped relative to the next. Clay shrinkage or a localised void could be responsible.

    What to do Ask for a specialist inspection before attempting cosmetic filler repairs.

  • Doors sticking in frames that used to close freely, worsening in summerSoon

    Seasonal swelling points to moisture changes in the soil. Shallow foundations on reactive clay respond to dry spells by shrinking away from the base.

    What to do Note which months are worst and mention this when asking for advice.

  • A gap appearing between the skirting board and the floorWorth watching

    Floor slab settlement sometimes occurs independently of the walls. It may relate to fill material compressing over time rather than structural failure.

    What to do Mark the gap edges with pencil and check monthly for further change.

  • New cracks in a garage wall separate from the main houseSoon

    Garages often have shallower footings than the house. They settle first, especially on made ground or where tree roots reach beneath them.

    What to do Check if the crack lines up with any movement in the adjoining house wall.

None of this diagnoses your particular home. If a crack has appeared suddenly or is widening week by week, ask about it now rather than waiting for warmer weather.

Towns covered across Hampshire

Enquiries go to specialists working throughout the county. Whether your home sits on chalk downland, river gravels or reclaimed coastal ground, there is someone familiar with the local soil behaviour.

If your village is not listed, send an enquiry anyway. Coverage extends across the whole county.

Ask about the cracks you have noticed

The details you send go directly to a specialist who handles foundation problems in your area. There is no fee for the initial enquiry and no obligation to accept any subsequent proposal.

  • No obligation to proceed
  • No upfront fee
  • Local specialist response

One independent subsidence specialist receives what you send here, and that firm may pay us at the point your enquiry is passed on. You owe this website nothing, quotations elsewhere are entirely yours to seek, and our privacy notice explains further what becomes of your details.

Or write to hello@hampshiresubsidence.co.uk