Can Subsidence Be Fixed Without Digging Up Your House?

Yes, in most cases. Screw pile underpinning stabilises a subsiding building without the excavation, concrete and months of disruption that traditional mass concrete underpinning involves. The piles go in through small access points, are torque-tested as they are installed, and can be loaded immediately.

Whether it is right for your building depends on what is causing the movement, which is the part worth understanding before anyone quotes you.

What you are actually worried about

If you are reading this, you have probably seen a crack that was not there last year, or a surveyor has used the word subsidence and your stomach has dropped. The fears, in the order people usually raise them:

•     The house will be uninhabitable for months. Traditional underpinning means excavating beneath the existing foundation in sections, filling with concrete, and waiting for each section to cure before starting the next.

•     It will cost a fortune. It can.

•     The garden will be destroyed. Mass concrete underpinning generates a great deal of spoil and needs machine access.

•     It will blight the property. Underpinning is recorded and is disclosed on sale - and that is true of any method.

•     The insurer will argue. They might.

What subsidence is, and what it is not

Subsidence is the ground beneath your foundation moving downward and taking part of the building with it. The common causes in this country are clay shrinkage, tree roots drawing moisture from clay soils, a leaking drain or water main washing out the ground, foundations that were inadequate in the first place - very common in conservatories, extensions and porches - and made ground that is still consolidating.

It is worth saying plainly that not every crack is subsidence. Thermal movement, settlement in a new build and ordinary plaster shrinkage account for a great many worried phone calls. The classic pattern worth investigating is a crack that is wider at the top than the bottom, runs diagonally, and appears both inside and out. One hairline crack above a door probably is not.

Get a structural engineer's opinion before you get quotes for remediation. It is the cheapest step available and it may end the story there.

Traditional underpinning compared with screw piles

	Mass Concrete Underpinning	Screw Pile Underpinning
Method	Excavate beneath the foundation in sections and fill with concrete	Install piles through small access points and transfer load through brackets
Excavation	Substantial	Minimal
Spoil to remove	Significant	Very little
Curing time	Each section cures before the next begins	None — piles are loaded immediately
Typical duration	Weeks to months	1-2 days
Access needed	Machine access and working space	Restricted-access (handheld) equipment available
Verification	Visual and inspection-based	Torque measured and recorded for every pile
Live in the house?	Often disruptive	Usually yes

The measurement point is the one engineers care about. Every screw pile records its installation torque, which correlates to its load capacity. You end up with documented evidence of what each pile carries, rather than an assumption about the ground you dug into.

Where it works particularly well

• Conservatories and extensions - frequently built on inadequate foundations, frequently the first thing to move, and frequently in exactly the sort of restricted rear-garden location where excavation and concrete are painful. Our handheld installation equipment gets into spaces a machine cannot reach.

• Foundations near trees - where you want to keep the tree, because it has a preservation order or because it is the reason you bought the house, screw piles let you transfer the load below the zone of influence instead of removing what is causing the problem.

• Occupied properties - less noise, less dust, less time, no concrete curing.

• Restricted access sites - terraced houses, rear gardens with no side access, town centre properties.

Where it is not the answer

• If the cause has not been fixed. Stabilising a building while a drain continues to leak beneath it solves nothing. Cause first, remediation second, always.

• If it is not subsidence. Underpinning a building suffering thermal cracking is expensive and pointless.

• Certain ground conditions. Shallow rock, significant obstructions or made ground with substantial buried debris can make installation impractical. A site investigation tells you.

• Where your insurer has specified a method. Screw piles are widely accepted, but on an insurance claim the scheme is agreed between the insurer and their engineer.

If this is an insurance claim

Most domestic subsidence is dealt with through buildings insurance. The usual sequence is that you notify your insurer, they appoint a loss adjuster, monitoring is often carried out over a period of months to establish whether movement is ongoing, the cause is investigated, and a remediation scheme is agreed.

Two things worth knowing. The monitoring period frustrates everybody, but it exists because remediating before you know whether movement has stopped, and what caused it, produces bad outcomes. And you can ask for screw piles to be considered - if speed, disruption or garden access matter to you, say so early.

What happens if you do nothing

Sometimes very little. Historic movement that has stopped may need nothing more than cosmetic repair, and a good engineer will tell you that rather than sell you a scheme.

Ongoing movement is a different matter. Cracks widen, doors and windows stop closing, services can fracture, and the eventual repair costs more than the early one. Selling becomes harder with an unresolved, undiagnosed problem than with a documented, remediated one.

The distinction between moved once and still moving is the single most important thing to establish, and it is what monitoring is for.

Find out where you stand

Send us the address, photographs of the cracking, and your engineer's report and data you already have. We will tell you whether screw piles are a realistic option for your building.

Frequently Asked Questions

1. Can subsidence be fixed without traditional concrete underpinning?

Yes, in many cases. Screw pile underpinning can stabilise a subsiding building through small access points with minimal excavation and no concrete curing. Whether it is suitable depends on the cause of the movement and the ground conditions.

2. How do I know if a crack could be caused by subsidence?

A crack that is wider at the top than the bottom, runs diagonally and appears both inside and outside is worth investigating. Not every crack is subsidence, so a structural engineer should assess the property before remediation is considered.

3. How long does screw pile underpinning usually take?

A typical domestic job is usually completed in one or two days, although the actual timescale depends on the property, access, pile requirements and ground conditions.

4. Can screw piles be installed where access is restricted?

Yes. Handheld installation equipment can be used in restricted-access locations such as rear gardens, terraced properties and other areas where larger machinery cannot reach.

5. Can screw pile underpinning be used near trees?

It can be particularly useful near trees because the piles can transfer the building load below the zone affected by soil movement while requiring much less excavation than traditional mass concrete underpinning.

6. What should I do first if I suspect subsidence?

Start by getting a structural engineer's opinion to establish whether the movement is subsidence and whether it is ongoing. The underlying cause should be identified and addressed before a remediation scheme is agreed.

For a real-world example, see our subsidence case study showing how 108 screw piles were used to stabilise a bungalow.