When new construction begins or when a repair is needed for existing infrastructure, one of the first steps in the process is excavation.  This is an extremely important step, and it consists of much more than just digging out earth and rocks. Excavation is necessary to ensure that there is a solid base for the foundation of the structure that is being built.

While there are many types of excavation, they can be divided into two main categories: mechanical excavation and vacuum excavation. In this article, we will discuss these categories along with examples of when they might be used.

Mechanical Excavation

Mechanical excavation makes use of heavy machinery that primarily involve hydraulic power such as excavators, backhoes and dump trucks to remove rocks and soil, but it can also include more labour-intensive methods such as shovels and digging by hand.

This method of excavation is most commonly used for large construction projects where there are no underground utilities to worry about damaging. Because of the amount of space that the equipment usually takes, this is also usually done in larger areas as well. Often construction projects will use a combination of mechanical excavation as well as vacuum excavation.

Vacuum Excavation

There are many types of equipment that utilize vacuum excavation but how the vacuum is created and the power of that vacuum is what’s most important. The first system commonly used is a Positive Displacement Blower, or PD system, which you’ll find on all hydrovacs. These systems generate suction power which is measured in inches of mercury (Hg) and can excavate soil at an average rate of 23 cubic yards per hour. The other option in vacuum excavation is a Fan System which creates air conveyance that is measured in cubic feet per minute (CFM). There are a wide variety of fan systems available in North America that all function around 1,000 CFM, these are for very small and unproductive digging jobs where not a lot of material needs to be moved. To be considered a true Suction Excavator, or Dry Vac, your fan system needs to achieve over 20,000 CFM, these systems are known to have an average dig rate over 40 cubic yards per hour.


Hydrovac excavation makes use of highly pressurized water and a special vacuum system that removes the earth. The water liquifies the soil so that it is more easily sucked through the vacuum and into a tank or truck.

Hydrovac excavation is popular in Canada because it can be used through the winter months, and it is a non-destructive technique that poses a very low risk of damage to underground infrastructure. For this reason, it is commonly used when gas lines or sewer pipes need to be exposed.

This method is also commonly used when holes for installing signs or poles need to be made.

Additionally, it is used for daylighting and potholing. Since hydrovac trucks can usually be placed far away from the dig site, they are extremely useful when the excavation is taking place in small or cramped areas.

Dry Vac Excavation

Dry vac excavation works similarly to hydrovac; however, instead of liquifying soil using water, dry vac uses pressurized air to break up soil which then enters into a powerful air flow or conveyance. Dry vacs are also considered a non-destructive form of excavation and can be used in many of the same scenarios that hydrovac can be used in.

There are, however, some instances in which dry vac is the better option. For example, the dry vac is the preferred choice when digging around electrical cables since air is not a conductor like water is. Dry vac is also the preferred choice if you want to preserve tree roots, if you want to reuse excavated materials, or if you’re simply looking to keep your work site dry.

Contact Super Sucker today

Do you require vacuum excavation for a maintenance, repair or construction project? If so, contact Super Sucker today. We will determine the most appropriate form of vacuum excavation for your situation and have the skills and equipment to safely perform a high-quality job at a competitive price.