What Is Basement Underpinning?

by | Jan 12, 2021

Whilst rural properties might have the luxury of building an extension or annex should they wish for a bit more space, inner-city homes are afforded no such thing. With space coming at such a premium, particularly in cities like London, one of the only truly economically viable alternatives is to build downwards.

Excavating a basement space underneath a property is known in the industry as underpinning. The team here at Borehole Solutions, who provide many of the various geotechnical services required when carrying out a basement underpinning, wanted to look at the process in a bit more detail.

 

Why Consider A Basement Space?

Whether you’re looking at it through investment-tinted lenses, in order to add value onto your property, or simply want more space within the home – common basement uses include games rooms, home cinemas and even swimming pools! – it doesn’t take long to realise just why creating a habitable space beneath your home is such an attractive proposition.

 

Do Basement Excavations Require Planning Permissions?

Typically, yes, underpinning a basement does require approval under building regulations. Securing that approval usually requires several stages, one of which is the digging of a trial pit in order to test and assess the ground conditions. These pits can either be excavated using a digger or by hand, and we offer both services here at Borehole Solutions.

The Party Wall Act 1996

Also important to consider is the potential implications of the Party Wall Act. If your property is standalone, then you’ve nothing to worry about. As we’ve already established, however, most basement constructions take place in crowded urban environments, the properties within which tend to share walls with one another.

More detailed guidance on the Party Wall Act can be found here, but the key thing to remember is that if you have neighbours whose property adjoins yours, you’ll likely have to get their consent to proceed with the basement underpinning.

 

The Underpinning Process

In terms of the underpinning process, itself, is a means of lowering the existing foundations of a building, so that it provides adequate space for the new basement. There are several types of underpinning used within the industry, the most common of which is probably the mass concrete pour, in which holes are dug below existing foundations and filled with concrete – either regular or reinforced. Alternatively, a process known as the beam method can be used, and for the most heavy duty, industrial underpinning projects, a process called piling is used.

 

How Much Does Underpinning A Basement Cost?

As with most construction/building projects, there are many variables when it comes to determining underpinning cost. In general, however, it will depend on where you live, the width and depth of underpinning required and any surveying costs incurred when settling Party Wall problems.

It’s worth looking around to find reputable contractors, and always err on the side of caution when it comes to pricings. If a contractor’s prices seem too good to be true, you’ve got to ask yourself what sort of corners they’re cutting? When it comes to something as serious and long-lasting as an underpinning project, you want it done right.

 

Contact Borehole Solutions

So, if you’d like to find out more about our various geotechnical services – which have proved essential in countless basement jobs over the years – then get in touch! Contact us today on 01733 200 501 or by emailing us at info@boreholesolutions.com.