Foundations – Piling Foundations for Domestic Buildings

The foundations upon which anything is built, be it a business, personal relationship or any number of other things are essential to how long it lasts and also whether it’s fraught with hassle and expense.

This is an even more true statement when it comes to building and construction, as, let’s face it, if the foundations of your building are not up to scratch then it could potentially come tumbling down.

With this in mind we thought we would have a bit of a look at the types of foundation available, starting with the little-knowing type – the piling foundation.

What are Piling Foundations?

This type of foundation is considered a ″Deep Foundation″ meaning that it should be used in situations where the ground is softer than normal and may not have the required load bearing abilities.

In terms of our reference to deep this normally means where the foundations go down more than 3 meters below ground level in order to reach more solid and stable ground so that any buildings built on the foundation will be adequately supported.

As you may have guessed, where deep foundations exist so do shallow foundations. These include the more commonly known foundations such as strip foundations, raft foundations and pad foundations (more can be found about these here).

How are Piling Foundations Constructed?

In most cases, piling foundations are a series of steel or concrete ″piles″ that are sunk down into the ground until a suitable stable depth is reached and then a ring of reinforced concrete beams are laid on top to form what is know as a ″ring beam″. Any structures are then constructed on top of the ring beam.

What Types of Piling Foundations are There?

For most domestic and commercial construction situations there are two sorts of pile:

• Displacement Pile: This type of pile is pre-constructed, shipped to site and then driven down through the ground using a special machine know as a Piling Hammer. This machine is capable of generating large amounts of force that is used to push the piles down through the existing soil until they are in situ, displacing the earth that was previously in their place
• Replacement Pile: Large holes are dug where each pile is to be placed and then either steel or concrete piles are put in each hole and secured. These piles simply replace the soil and earth that was previously there

Are There any Up-Sides to Foundation Piling?

As I’m sure you can imagine, in the event that it is confirmed that you need foundation piling for an existing structure or one that you are building, you could literally visualise the pound coins rolling out the door and to some degree this is the way it is. The unforeseen costs of a project can sometimes seal its demise.

However, once the dust has settled and you have resided yourself to the fact that the piling has to happen, at this stage you may like to consider geothermal piles.

This type of piling is constructed in such a way that you can incorporate a ground source heating system into the property that you are installing piles into.

In basic form, plastic piping is added to the inside of the piles that is then filled with a heat transfer fluid. The pipework is then connected on a new circuit to the internal heating system within the building allowing you to use heat that is contained within the thermal mass of the ground to heat the building – free heating!

This system also works on the flip side – in warm climates, unwanted heat from a structure can be captured and fed into a system such as this and then piped out and dispersed through the ground.

Obviously this type of system comes at a greater expense as not only are specialist piles involved but also all the pipework and heat exchange equipment that goes with a system of this type, but if you look at it in terms of what you could potentially save in heating bills, then it’s certainly worth considering.

What Effects the Type of Pile That can be Used?

When it comes to the type of pile that you can use, this depends on several factors that include:

• The type of structure that is going to be supported
• Where the structure is situated or is going to be situated
• How accessible the site is
• How close it is to any other surrounding buildings
• Is it going to be situated near or over water
• What the current state of the ground is

Overall, displacement piles tend to be the most cost effective but they cannot be used in every situation due to the effects on surrounding buildings when they are driven down into the earth and the subsequent vibrations that result.

Where large amounts of earth need to be removed to sink the piles down, it is often cheaper to have the piles bored down into place.

Where an already existing structure has been effected by subsidence or requires piling, jack piles are normally the way to go. For this type of pile, the existing foundations of the building are excavated and the piles are driven down in sections below. Any removed or damaged foundations are then reconstructed to provide a stable base.

When access is quite tight or very restricted mini piles can be used. Again the clue is in the name – These are generally quite small and due to this they can be screwed or driven down into the strata without the need of large, specialist equipment.

Quite often, cost is one of the biggest factors in the decision process and this can be effected by a fair few things:

• Materials and time needed to construct piles
• The cost of the piling compared against the building that is going to be constructed
• The preparation that is required to the site e.g. access, excavation, repairing the site after works are completed
• The cost of the skill and knowledge required to design, test and construct piling

If you are interested in finding out more about piling foundations, how they are used and the different types commonly available then check out our project page here.