3 Basement Shell & Core Methods Worth Trying


February 17th 2016 | Back to news

There are many methods of basement shell and core engineering methods available, so knowing which one is best to use on a property can be somewhat mystifying. In order to help, we’ve outlined the three most common methods - so you can better understand which is the best fit for your basement project.

1. Basement Underpinning

Underpinning is the method of extending foundations down below between 3.5 and 4 metres to create more vertical space under a property. This is the most popular way of building a retrofit basement or extending an existing basement to give more headroom.

Existing foundations are extended by fitting two or more anchor poles in the centre of the basement to bear the load of the upper floor. Once the cement has settled around the anchor poles, the adjacent pins can be excavated safely, wall by wall, until the new foundations are in place.

Underpinning is a complicated process and needs to be planned by a professional structural engineer. This engineer will provide structural calculations and drawings which will need to be submitted to local authorities for approval. Once the construction has been checked and approved, the owner will receive a certificate to prove the basement is safe and ready for moving in.

2. Secant Piled Basements

In places like London where ground conditions aren’t ideal or the water table is too high, a technique called secant piling may be used. This innovative method of constructing retaining walls involves building a set of interlocking bored concrete piles with small gaps between and is often used for large commercial basement projects too.

Secant piling tends to be quieter and more compact during the building process than other methods and forms a more watertight wall in areas with a great deal of groundwater. These piles can tend to look rough so the finished product will be covered with an inner wall ready for decorating.

3. Contiguous Piled Basements

Very similar to secant piles, contiguous piles are interlocking piles used in adverse conditions or commercial buildings. The difference is that contiguous piles have a much smaller gap between each pile, less than 100mm and often virtually touching each other. This is to provide extra structural strength and waterproofing where needed.

Which type of basement shell and core method you choose depends on the type of structure you’re building, your conditions, and your budget. Speak to one of our expert team members at Knowles to find out which is best for you.

knowles basement retreat