Portsmouth · Hampshire
Subsidence repairs in Portsmouth
Cracks in a house in Portsmouth are not always subsidence, and subsidence is not always serious. The first job is to find out what is moving and why, whether that is a leaking drain, a nearby tree or soft ground under shallow footings.
Guide price from£2,800per property inc VAT

- Postcodes
- PO1, PO2, PO5
- Population
- about 210,000
- Area
- Hampshire
- Pricing region
- South East
What should you know about the ground under Portsmouth?
With roughly 210,000 people, Portsmouth spans postcode districts PO1, PO2, PO5 in Hampshire. Neighbouring towns we cover: Fareham (5 miles), Hayling Island (5 miles) and Havant (6 miles).
Much of Hampshire sits on clay that shrinks in dry summers and swells in wet winters. Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in Hampshire: Victorian terraces in Portsmouth and Southampton, 1930s semis, and large post-war and new-build estates.
What to expect when we carry out subsidence repairs
Send photos or call
Send photos of the cracks with a coin or tape for scale, and say when you first noticed them. We give a free initial assessment and suggest whether an engineer, a drain survey or your insurer comes first.
Deal with the cause
Drains are repaired, vegetation is managed on the engineer’s advice, or a foundation scheme is designed if nothing else will work. Where monitoring is recommended, readings run for several months to show the movement has stopped.
Repairs and making good
Cracks are stitched and repointed outside, plaster is renewed along the crack lines inside, and sticking doors are eased. Where the work needs it, we deal with building control and hand over the paperwork.
Is it time for subsidence repairs? Common signs
- Wallpaper rippling or tearing where the wall meets the ceiling
- Diagonal cracks wider at the top, running from window or door corners
- Doors and windows that start to stick or no longer close
What should you budget for subsidence repairs in Portsmouth?
For Portsmouth we use South East rates. Treat the table as a budget guide, inc VAT; the price you pay is the one on your written quote.
| Item | Guide price | Per |
|---|---|---|
| Structural engineer's investigation and report | £560 – £2,250 | per property |
| CCTV drain survey (common first check) | £170 – £390 | per survey |
| Typical repair once the cause is dealt with: crack stitching and making goodest. | £2,800 – £13,400 | per property |
| Foundation strengthening where it is needed (see underpinning) | £1,100 – £3,900 | per metre of wall |
Repair options we may recommend
Foundation strengthening
Where the ground cannot be made stable, the load is carried down to firmer soil by underpinning, a beam-and-base scheme, mini-piles or resin injection, depending on the soil and access. It is designed by an engineer and is the exception, not the rule.
Best for: Ongoing movement where removing the cause has not worked
Crack stitching and making good
Once movement has stopped, cracked brickwork is cut along the bed joints, stainless helical bars are bonded in to tie the wall together, and the joints are repointed to match. Inside, plaster is renewed along the crack line before redecoration.
Best for: Category 1 to 3 cracking in walls that are otherwise sound
Rules for subsidence repairs in England
In England, underpinning and other work that alters or strengthens a wall or foundation is building work under the Building Regulations (Part A, structure), so building control approves and inspects it. Like-for-like repairs often are not, and we tell you which applies before a price is agreed. Work to a party wall, or excavation close to a neighbour’s foundations, can also need a notice under the Party Wall etc. Act 1996.
Your subsidence repairs questions
How much will subsidence repairs cost in Portsmouth?
Guide prices for subsidence repairs in Portsmouth start from about £2,800 per property, including VAT, on South East rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Portsmouth?
We do. Portsmouth and the surrounding area are covered, including nearby Fareham and Hayling Island. A free initial assessment from your photos is the first step.
Is the ground in Hampshire prone to subsidence?
Central Hampshire is chalk, while the south around Portsmouth, Southampton and the New Forest fringe and the north-east around Farnborough sit on London Clay, Reading Beds and other clays and sands. The clay areas see seasonal movement near trees. Only an investigation can say why a particular building has moved.
Can I sell a house that has had subsidence?
Yes, though buyers and lenders will want paperwork. Keep the engineer’s report, monitoring results, the repair specification and any building control sign-off. A repaired house shown to be stable is far easier to sell than one with an open problem.
Should I cut down the tree near my house?
Not without advice, because felling a mature tree on clay can make things worse. As the roots stop drawing water, the clay swells and can lift the foundations, which is called heave. Pruning or staged removal may be advised instead. Check whether the tree is protected.
Other structural repairs in Portsmouth
- Bowing wall repairs
- Roof structure repairs
- Lintel replacement
- Bay window subsidence repairs
- Chimney stack repairs
Subsidence repairs near Portsmouth
If your insurer is already involved, send us the loss adjuster’s schedule for your Portsmouth property and we will price the repairs to it in writing.