What is piling?
If anyone asks what are piles, a simple answer might be “long holes in the ground filled with concrete!”
However, the more technical response is:
A piled foundation solution may be required if the underlying near surface ground is not suitable for traditional shallow foundations, due to weak or loose soils, or a high-water table.
Deep, compact, stiffer soils are more suitable to support traditional domestic extensions, or even more so to support much larger developments with heavier loads.
Therefore, piles act as distributors of the loads that are required, down to these stronger, stiffer soil types often found at depths.
Some piles for domestic single storey extensions may be formed at 6-8m deep (average), whereas for multi storey buildings with heavier loads can be as much as 40m below ground, or even more.
The depths and types of piling required will always be determined by two things:
1. The loadings required by the structural engineer,
i.e. How heavy is your building?
Or in other words, what impact is the weight of your building going to have on the ground you are building on?
This is calculated by the engineer, and it’s based on the architects’ design/requirements for your project
For example:
- Is it a timber frame?
- Is it a traditional brickwork and block work construction?
- Is it a structural steel frame?
All factors that can increase/decrease the weight required for each pile so that it can carry/transfer this weight down to a firmer soil type or strata.
2. Soil Type
London and the surrounding counties are made up of various different soil types, and depending on which soil type you have this has an impact on which piling you require.
These soils include:
- Clay
- Sand
- Ballast
- Rock/Stone
- Alluvium
- Chalk
A soil investigation is often recommended to assess the make-up, strength and suitability of the underlying soils.
In-situ (on site) tests, as well as soil laboratory testing, can determine the characteristics of the soil, which then allows us to calculate the design parameters for your pile, i.e. diameter (width), length (depth) and how much reinforcement and concrete type is required within the pile.
This in turn will also help determine your foundation solution.
Soil tests include shallow or deep boreholes which can be drilled on site with samples taken every 0.5m
Also, simple Trial pits can be dug on site by hand, or can even be done by using a mini excavator. This can then expose the soil type at 1-3m deep, and/or expose some existing foundations so that we can then have a full understanding of what you need and require for your project. Getting this right at this stage is critical, because without proper investigation and knowledge for what piling you require , we could be succeptible to very costly changes.
Step by step process to piling your project.
1. A site visit
Having a site visit will determine the existing site conditions and any access restrictions. This will inform us as to what type of piling rig we can get onto your project, and any other machinery and plant equipment necessary, including; Diggers, air compressors, skips, concrete lorries, muckaway lorries etc.
There is nothing more frustrating that turning up to a job and not being able to get on site, as the entrance is restricted or not big enough for our machinery.
Parking, works traffic, and being considerate to your neighbours is also a very important element of every job.
2. A foundation design
Our foundation engineer will liaise with yourself and or your architect to determine what we need to achieve to “get you out of the ground”.
You may already have an engineer on board who could be willing and able to take on this aspect, we will ten work to these designs, drawings and calculatons.
This design will give us an indication of the number of piles required, and the loadings each pile needs to carry.
3. A soil investigation
As mentioned previously, this will determine the soil types and parameters we have to work with in order to calculate our pile design.
4. Pile Design
Using all of the information gathered from the first three steps, we now have what we need to:
- design the type of piling
- determine the sizes of the piles required
- design the concrete required to form the pile
- design the reinforcement required within the pile.
- Finally, and, most importantly, calculate the costs of your piling
Piling costs are determined by;
- Method of piling
- Pile diameters
- Pile lengths
- Type of Concrete or grout (sand and cement mixed on site)
- Amount of reinforcement required
- Site access/restrictions.
All of these factors will have a bearing on your costs.
Once an estimate has been produced, and you approve to go forwards, then the following will happen.
Site Mobilisation
The fun begins! All of the necessary piling machinery will then be transported to the site. This includes all of the tools and materials that are required to carry out the work.
The area will be cleared of any visible obstructions, including breaking out pile locations (if necessary) – which may be required if there are existing foundations, or concrete oversites within the new foundation area.
Any drainage/manholes will be highlighted/protected, and this will have been noted in the initial site visit and included in the foundation design. This is why this step is really important, as you don’t want a pile to go through your sewer pipe or any other services (water, gas , electric etc)
Piles will then be set out as per the foundation/engineers design.
Reinforcement will be fixed/tied on site ready for each pile.
The piling rig is set up over the first pile position, and away we go..
Concreting or grouting of each pile is completed at the end of each day, and the above process is repeated until you are “Piled”…
All arisings from the piling, i.e. the muck that comes out of the ground in drilling piling methods for example, will be cleared via skips or muck away lorries including any rubbish resulting from this work.
Then the piling rig, all plant and leftover materials (if any) will also be removed.
You are then left with your Piles, ready for the next part of your foundation design.
What are the benefits of using us ?
As you can see, there is a lot to consider when undergoing any construction work. Getting all of the pre-piling work sorted and done correctly is really important. This is why we offer a comprehensive service which includes everything I’ve shared. We can do the lot.
From the initial site visit and consultancy stage, to the soil investigation and analysis stage, including the in-house complete piling and foundation design by our fully competent and professionally indemnified engineers, to the setting out and physical installation of the piles themselves, we’ve got you covered.
Knowing how our process works gives you a much better understanding of the project, and it also tells you of what to look out for.
Not all piling is the same. Now see our other pages for the methods of piling we offer.