Have you ever heard of the word underpinning? It is a common word used in residential construction to define the lowering of foundation through the use of digging under existing foundation. It sounds dangerous, and it is if the people completing it do not know how to do so. You can find an article in the Toronto Star of a home who hired people who did not know what they were doing here.

This has unfortunately given the word underpinning a bad name when people hear it now, but what is underpinning? And is it actually that unsafe?

Underpinning essentially helps to lower basements. The existing foundation is dug under in sections, and new foundation is set by pouring concrete under the existing foundation, thus lowering the foundation and giving higher ceilings in a basement. Since ceilings in basements in Toronto are low in most areas with older homes, this method has been tried and tested in many different parts of the GTA. Below is a video of our BVM crew completing a stage of underpinning:


Is this method safe though? Yes, if a qualified contractor is given the job, and all safety precautions are followed, then there is a very low chance of anything going wrong. A qualified underpinning contractor will do the following things:

  1. Ensure that the permit drawings for the underpinning process are followed correctly, and that close correspondence is kept with the engineer that approved the permit drawings throughout the duration of the project. The engineer should be called into the site after every stage of the underpinning (which will be explained).
  2. Make sure that a city inspector is called to inspect the project, in order sign off on each stage.

There are different stages to underpinning jobs (as eluded to above), in order for the home to remain structurally sound. The amount of stages completed in a usual underpinning job is usually three. Each stage completed in underpinning jobs consists of:

  1. Digging under the existing foundation to the desired amount of depth.
  2. Creating a form to allow the concrete to set into the dug under area of the existing foundation.
  3. Pouring the concrete into the form, and allowing it to cure under the existing foundation.
  4. Removing the forms, getting the sign-off from the engineer and city inspector, and moving on to the next stage.

Vince Meagher explains one of our recent underpinning jobs in the video below, which was completed in the East York area of Toronto:


It is important to be knowledgeable and do your homework before you decide which construction company to trust with your project, but it is also equally as important for the company undertaking the project to know how to complete the project in a safe and effective way. BVM Contracting has all of the tools to deliver you any type of Home Addition or Home Renovation you desire. Just remember, even if we are not your company make sure that the company you pick has all of the necessary credentials before letting them alter your living space.

Ryan Meagher, Guest Blogger, BVM Contracting - Home Addition and Home Renovation Contractor.

About the Author

Ryan Meagher

Business Development, BVM Contracting

A graduate of chemical engineering from Queen's University, Ryan has spent many summers working with BVM Contracting in various roles and projects. This experience has provided him with a unique view on the residential construction industry which he loves sharing with you!