U&M Group


Underpinning repairs | Underpin

When Is Underpinning Needed?

Underpinning — some people panic at the idea of it, but it’s only a technique for safeguarding your home. Our underpinning constructors use Underpinning to strengthening the existing foundations of a building, and there are a number of reasons why this might be needed. 


What Might Create a Need for Underpinning Your Home?


The most common reason for needing a underpinning constructor to underpin your home or commercial building is subsidence, where the subsoil under the foundations can no longer fully support the weight of the structure.  Subsidence can have a number of causes, not all of which require underpinning. For instance, if a tree root is growing under the foundations or the drains are leaking into the subsoil, fixing the issue should be enough.


However, the soil could have been weakened over a period of time, or the water table may have risen. Alternatively, there may be excavations under the building, such as old mine-workings, and this could lead to collapse of the soil, causing your house to subside. In these cases, it’s likely that you’ll need underpinning to prevent the building falling into ruin.


Underpinning is most often a reaction to a situation that’s out of your control, but not always. If you’re increasing the load on the foundations, for instance by adding an extension or building an extra storey, you may need to strengthen the foundations at the same time by underpinning


What Are the Signs of Subsidence?


The most obvious sign of subsidence is likely to be cracks developing in the walls, either inside or outside. Not all cracks are a cause for alarm, especially if they’re very narrow, but substantial cracks could well be a sign of trouble. Similarly, subsidence may well result in the door and window frames pulling away from the masonry.


These are signs of potential trouble, but they aren’t necessarily reasons to have your home underpinned. You’ll require a professional survey, which will tell you how serious the problem is and what the recommended solution is. It’s possible that all you need is to get your drains repaired.


Are There Drawbacks to Underpinning?


The biggest potential drawback to underpinning is its cost — though it would cost far more to rebuild from scratch because your home’s collapsed. However, this isn’t necessarily as bad as it may seem. It’s quite possible that your building insurance will cover work to rectify subsidence.


Many people claim that it’s difficult to insure an underpinned house, and you might find a general insurer reluctant to take this on. However, there are many specialist policies from insurers who recognise that underpinning has made your home more secure, not less.


Get in touch with us if you think your home or business premises may need underpinning, and we’ll talk over your requirements.

Mini Piling vs Traditional Piling Methods

Piling represents a range of techniques by which steel or concrete are inserted into the ground by either driving or drilling down to a substantial depth. It’s used when the ground is unusable for the first couple of metres, or where a high water content makes it unstable. It can also be used as an alternative to the high costs of removing deep trench foundations.

There are many types of piling, but in recent years mini piles (sometimes called micro-piles) have become increasingly popular. So are they better than traditional methods?

Traditional Piling

The various traditional piling methods each have their roles, especially in large, open sites and large construction projects. Driven piles are particularly useful for offshore use, though they can be used on land too. Their great advantage is that, because they penetrate the ground by displacement, the soil at the toe is compacted, giving the pile the ability to support a considerable load.

Bored or drilled piles, on the other hand, are used more often in urban environments. In this system, a shaft is drilled and concrete is poured in, creating a pile in situ. They create considerably less vibration than the driving process.

Mini Piling

Mini piling involves driving or screwing hollow steel shafts into the ground, which then have concrete or grout poured in to form a pile. Though this has similarities to the drilled pile system, the soil is supported throughout by the steel shaft, so there’s no need to add extra supports if the soil is weak. One variation is sectional auger mini piling, where the shaft is inserted in segments. This is particularly useful in settings with limited headroom.

Mini piling is often chosen for underpinning, since it requires less space for the far smaller rigs used. This also makes it useful for any project where the space is limited or access is difficult, but also in difficult ground conditions or when environmental factors make it necessary to minimise noise and vibrations.

Mini piling is also suitable for larger-scale projects, though. It’s been used successfully to support bridges, electricity pylons and offshore wind farms.

Which Is Better?

There’s no simple answer. Traditional piling continues to be the best option for large projects where a substantial load needs to be supported. On the other hand, uses for mini piling are increasing and it’s proved effective on surprisingly large-scale constructions. It’s unlikely that mini piling will completely replace traditional techniques, but perhaps it will eventually become the norm.

If you have a project that may need an expert piling service, get in touch and discuss it with us.