Rising home prices in Toronto over the last few years have made it difficult for many homeowners in search of additional space. Torontonians not willing to move to the suburbs and not able to buy a new home in the city they love have been left with two options to increase the livable space of their existing homes:

  1. A home addition: While a great way to add space to your living area, additions can be costly, disruptive, invasive, and in many cases not feasible.
  2. Basement lowering or “underpinning”: This is a much more cost effective way to improve the functionality and utilization of your current home.

What is basement lowering?

With basement lowering, you dig down and excavate the dirt below an existing basement floor and support the foundation wall to the new depth. This increases the height of your basement, and depending on the length and width, allows for the incorporation of bedrooms, bathrooms, rec. rooms, a finished laundry room, organized storage spaces, or an enclosed utility space.

Permitting and construction

Basement lowering requires permitting and a structural engineer.  Lowering a basement involves alterations to a home’s foundation and must be carefully completed by professionals using the sectional sequence method. With this method, you divide the foundation into sections (1,2,3, 1,2 3, etc.). Then, all 1s are excavated, steel rebar is installed, the wall section is formed and filled with concrete. This process continues with all section 2s, 3s, etc.. Once complete, the middle of the basement is dug down and the new concrete floor is poured at the new desirable basement height (typically around 8’ finished floor to ceiling).

Costs and benefits in Toronto

Additional costs to considered for your basement lowering projects include: modifying structural supports, new basement plumbing, installing a sewage ejector (if the home’s main drain is above the new finished basement height), mechanical alterations, and added/new stairs from the main floor to the basement.

Basement lowering offers some additional benefits including better climate control and energy efficiency of your home as well as a dry basement. This is because these projects require waterproofing and insulation from the inside. Waterproofing requires the use of interior weeping tiles, a high density polyethylene membrane and a sump pump. Additionally, all exterior walls must be insulated to a minimum of R-22.

It is important to keep in mind that depending on the home, scope of the project, and time of the year, basement lowering can be a disruptive process that may require a home owner to move out until all mechanical systems are restored. If you are unable to move, you can opt to use portable fans in the warmer months and electrical space heaters in the colder months. Good contractors will be up front about the process, set reasonable timelines.

If you have any questions regarding basement lowering please feel free to contact us.

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