Do all sinking foundations really need traditional underpinning?
When homeowners hear the word “underpinning” they pretty much assume the worst – weeks of mess, a huge bill, and all the hassle that comes with it. But as experts working in London, Birmingham, Yorkshire, Wales and the whole of the UK, we know that traditional underpinning isn’t always the only answer. Not every sinking or cracking property needs to be treated like it’s a major crisis.
Our job is to figure out which solution is the best fit for the problem. That usually means exploring all the alternatives we have, before deciding that full underpinning is the way to go.
So why did underpinning become the “default” recommendation?
For a long time, mass concrete underpinning was pretty much the only widely recognised option for serious subsidence. It was a tried and tested method, easy to understand and familiar to everyone involved.
When underpinning still makes sense – but only when it really is necessary
Where there’s been a lot of movement, the loads are especially heavy, or other options just won’t work, then traditional underpinning still has a role to play. But we don’t automatically assume that’s the answer – we need to take a closer look at the actual problem before deciding what to do, because there are quicker, cheaper and equally reliable solutions that are available.
Why engineers now consider alternative options first
These days we have a whole range of new materials, better equipment, and a much deeper understanding of how the ground behaves. That means we’ve got more tools in our kit bag than ever before, and we can often stabilise a property in a way that’s less damaging and less intrusive.
Resin injection: a better way to avoid full-scale underpinning?
Geopolymer resin injection is one of the most common alternatives we use to avoid full underpinning, especially when access is tight or tricky.
How resin injection works to stabilise weak ground
We drill small holes in to the ground under the foundations and inject expanding resin into the ground. As it sets, it fills in the gaps and strengthens the soil beneath the foundation, sometimes even allowing us to gently lift affected areas back into place.
When resin is a good alternative to mass concrete
We tend to favour resin when movement is localised, the soil is in a good state to be improved, and the disruption of traditional underpinning just wouldn’t be worth it. However we regularly treat and stabilise whole buildings, complexes and slabs!
The limitations of resin underpinning on certain soils
Resin injection can be used in most cases. However in some ground conditions it is less suitable and in those cases, we might use it alongside other methods, or opt for recommending something like piles or traditional underpinning.
Piled solutions – mini-piles and micro-piles
Another key area of alternatives we look at is piled solutions. If we think these are the solution we will recommend other contractors that could help.
How piles transfer load to deeper ground
Instead of relying on weakened shallow soils, piles transfer the load to deeper, more solid strata. They’re installed through or next to the existing foundations and then connected to the structure.
When piles are the better option – and why
We tend to favour piles where there’s deeper, more solid ground available. We do that because where movement is serious or long-standing, or loads are high and the building is particularly sensitive. We can recommend contractors to do this work if needed!
Targeted ground treatment – localised repairs that make sense
Not every solution involves major structural systems across the whole footprint.
Focusing on specific areas – walls, corners, and bays
We often design schemes that target specific walls, corners or bays rather than the whole house. This can involve resin, piles, or other ground-improvement techniques, all focused on the affected area.
The hybrid approach – combining methods on complex properties
On more complex properties, the best solution can be a mix of different methods – resin in one area, piles in another, plus drainage and vegetation management. The goal is always a stable, predictable structure, rather than trying to force a one-method-fits-all solution.
Real life examples: fixing specific issues
Typical examples include a sinking bay window on a terrace, a dropped extension, or a corner of a house affected by a nearby tree or leaking drain.
Fix the cause, not just the symptoms
The most overlooked “alternative to underpinning” is dealing with the root cause.
Drainage repairs – fixing problems before they cause more chaos
We see a lot of cases where leaking drains are undermining the soil, or surface water is being poorly controlled, causing the ground to soften. Fixing those issues can be more important than any structural measure.
Managing trees and roots on clay soils
On clay soils, large trees and substantial shrubs can have a big impact on moisture levels. Management can involve pruning, root barriers or even removal – but with a clear strategy for dealing with potential heave or dealing with voids made by tree roots.
Monitoring before and after any structural work
Monitoring allows us to confirm whether movement is ongoing before we intervene, and prove the effectiveness of repairs afterwards. It’s not always necessary, but it can be very helpful in borderline cases.
How we compare underpinning vs alternatives
We take a good hard look at soil conditions, building type, how bad the movement is and what its pattern is, how easy it is to get access to the site, how much risk tolerance you have and what the cost is going to be. In most cases resin injection is a good solution, but if not we will recommend the alternatives.
Questions to ask any contractor you’re thinking of hiring
Homeowners need to feel free to ask:
• Why did you choose this method and not a different one?
• What are the other options available?
• How do you plan to sort out the cause of the movement rather than just patching up the symptoms?
• How will you actually know that the repair has been successful?
Why knowing the type of movement is key
Before we can even start suggesting a method for fixing the problem, we need to work out whether we’re looking at subsidence, settlement or heave. That’s the foundation of any repair plan.
Why the cost of resin, piling and traditional underpinning varies so much
It all depends on the method you choose, how deep you need to dig, how much of the site you need to cover, how easy it is to get to the site, where you are and what kind of follow up work you need to do – like making the house look nice again. Each method has its own set of costs and there’s no one size fits all “cheap option” that suits every situation.
What to send us before we come and take a look
Send us some photos, any reports you’ve got already, any letters from your insurer and a bit of background info on when the first cracks started appearing would all be a big help.
How we do subsidence surveys, and how we help
We take the same structured approach to every site we visit: we understand the building, we understand the ground, we figure out what’s causing the problem, then we match the method to the job. Having a good understanding of the local soil conditions helps us avoid making the same mistakes over and over again.
Contact Subsidence Ltd
If you need to get a repair cost estimate or need any advice on subsidence repair, contact us today online or phone us. You can also use our repair cost calculator to get a cost estimate.
Frequently Asked Questions – Underpinning Alternatives
What are the other options to traditional underpinning?
Resin injection is one, piling is another and targeted ground improvement is a third – in most cases resin injection is a viable solution.
Is resin injection better than underpinning?
It depends on the ground conditions, how bad the movement is and what kind of access you’ve got. Resin injection is a tried and tested solution and is normally cheaper and less invasive than traditional concrete underpinning. Read more about the differences between resin injection and underpinning .
When would you use piles instead of underpinning?
Piles are usually better when the ground is deeper down and more stable, or if you’re dealing with really heavy loads or really unstable shallow soils.
Can you fix sinking foundations without digging up the whole garden?
In lots of cases yes, you can. Resin injection and some piling techniques are a lot less invasive than traditional underpinning.
Do underpinning alternatives get approved by insurers?
More and more insurers are accepting resin and piling as alternatives to underpinning, provided they’re properly designed and supervised.
Which is cheaper – resin injection, piling or underpinning?
In most cases geopolymer resin injection is the cheapest alternative solution.
How do you know which foundation repair method is right for your house?
You need a proper investigation and an engineer’s recommendation that’s tailored to your soil, your building and the pattern of movement.
Do you need a structural engineer before choosing an underpinning alternative?
We can give you the initial advice and, where appropriate, a solution for your situation. Where we feel that a structural engineer should get involved, we will always tell you this. Where we feel that resin injection is not the answer, we will also always recommend alternative solutions!
