In the competitive world of construction, it’s more important than ever for civil contractors to be efficient and profitable. However, many contractors are making costly mistakes that are eating into their profits. In this article, we’ll discuss three ways civil contractors are leaving money behind and offer tips on how to avoid these mistakes.
Bulking Factor
In the construction industry, the bulking factor refers to the increase in the volume of soil when it is dug out of the ground. This is because soil particles tend to spread out when they are disturbed. Civils contractors should factor in the bulking factor when estimating costs for excavation work, as it can significantly affect the amount of material that needs to be removed and disposed of.
Bulking Factor Example:
Imagine a civils contractor is bidding on a project to excavate 100 cubic metres of soil. The contractor estimates that the bulking factor for the soil is 20%. This means the soil volume will increase by 20% when dug out of the ground. As a result, the contractor will need to remove and dispose of 120 cubic metres of soil.
If the contractor does not factor in the bulking factor, they will underestimate the amount of work required and may lose money on the project.
Here is a table that shows the difference in the volume of soil that needs to be removed and disposed of, depending on whether or not the bulking factor is taken into account:
| Bulking Factor | Volume of Soil to Remove |
| 0% | 100 cubic metres |
| 20% | 120 cubic metres |
| 30% | 130 cubic metres |
As you can see, the bulking factor can significantly impact the amount of work required for excavation projects. Civils contractors should always factor in the bulking factor when estimating costs for excavation work.
As a rule of thumb, at Carroll Estimating, we allow 30% for the bulking factor and use this formula to calculate it:
Bulking factor = (Original volume * Expansion factor) / Final volume
Conversion Rates
Conversion rates are another area where civils contractors often lose money. Whether it’s tonnage, cubic meters, or converting between different measurement units, inaccuracies can lead to substantial financial discrepancies.
For instance, tilers might find a notable difference in cost when converting from square yards to square meters. To avoid unexpected losses, it’s essential to stay up-to-date and accurate with these conversions.
Dayworks vs. BOQ Rates
Dayworks and BOQ rates are two different methods of pricing construction work. Dayworks rates are used for work not specified in the bill of quantities (BOQ), such as site visits, minor repairs, and unexpected changes to the project scope. BOQ rates are used for work that is specifically detailed in the BOQ.
When faced with the choice between daywork rates and Bill of Quantities (BOQ) rates, contractors need to tread carefully. You might have a reasonable rate for a reduced level dig in your BOQ, but what if you’re asked to do an additional dig on a daywork rate?
Deciding which is more profitable requires deeply understanding your costs and the potential “leaving money behind” in such scenarios.
Generally, dayworks rates are more costly than BOQ rates, so contractors should be careful not to overuse them.
Conclusion:
By following the strategies outlined above, civils contractors can help to minimise the risk of leaving money behind and improve their profitability. By carefully considering bulking factors, conversion rates, and dayworks vs. BOQ rates, contractors can make more informed decisions that will save them money in the long run.
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