The Hidden Costs of Piling

A constant frustration with purchasers of piling solutions is the difficulty in comparing prices of different options.

As there is no standardised Bill of Quantities for each piling solution, it is often difficult to compare one CFA piling quote with another. However, the real difficulty arises when comparisons are being made with alternative systems, such a Precast Concrete Driven Piling and CFA Bored Piling. Regrettably, this is often complicated by piling contractors omitting some cost headings, such as clearing spoil away from rigs and the cost of removing excessive materials/spoil arisings from site. Furthermore, the level of Main Contractor attendances required can vary drastically – a cost that is often not known until work commences on site.

For example, the cost of providing an excavator in full time attendance to a CFA piling rig to remove spoil arisings from the area of the piling during boring is rarely detailed in piling quotations. Further costs associated with boring out piles is the cost of removing and storing spoil to a tip on site for drying out prior to loading and removingthe spoil from site. In most cases, the Main Contractor must allow additional sums in their cost estimated for this work. Typical cost per metre of pile for this work, based on a 450mm dia pile is €5/m or circa 15% of the quoted pile cost! If the project happens to be in a ‘brownfield’ site, the cost of disposing of spoil from site can be very expensive indeed (we are aware of costs exceeding €500 per m3!)

Precast Concrete Driven piles can also present difficulties in relation to unspecified costs. The most common is the cost of excessive pile lengths over ground. In most cases the costs of these piles is transferred to the Main Contractor at the full BoQ rate – even if the pile lengths are +3m above pile cut-off / working platform level. As you might imagine, this is a cause of contention! A further cost associated with this issue is the subsequent cost of removing these excessive and wasteful lengths of pile from site – often landfill site do not want to accept them.

As with all of these types of issues, the devil is in the detail, and the specifics of who is responsible for what must be agreed prior to engagement. The simplest solution is to make the piling contractor responsible for all the waste and spoil generated on site – then a direct comparrison can be readily made.