Basement Excavation Project: Creating Extra Living Space

By Editorial Team

Updated on October 31, 2025

Digging out a basement is a complex building project that leaves no place for improvisation. The slightest error could cause the house to collapse. It is a delicate process, especially if the house contains walls that are shared with other buildings.

Any damage caused to neighbouring houses would fall under the owner’s responsibility. However, in a lot of cases, it can turn out to be worth it, as it will create an extra living space.

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Checking the feasibility of the basement excavation project

The cost, the amount of risk involved and the general feasibility of the project vary depending on several factors. In all cases, you’ll have to contact a professional who will determine if the project is doable and will be able to select the adequate methods to carry it out.

Don’t forget to make sure that your new space will satisfy the requirements in terms of natural light sources that are mentioned in the National Building Code. Also, check the height of the municipal sewers to make sure that the basement drain will be able to function properly.

Contacting a qualified professional to determine the work that needs to be done

Your excavation expert will adapt his methods according to the current foundation’s structure, its location, the possible presence of groundwater, as well as the quality and type of soil that they will have to work with. This step is crucial as it is then and there that you will be able to determine whether or not the basement excavation process is possible. If the project is deemed feasible, the expert will examine the foundation closely and make a plan for the following steps.

Digging out a basement that already exists

Digging out a pre-existing basement is a great option for people looking to increase the amount of livable space in their home. Older houses often have crawl spaces or partial basements which aren’t big enough to use as rooms. In these cases, excavation work can be carried out by lowering the ground level. The cost for this type of project is generally lower than that of creating an extension.

Working with an excavation company

Needless to say, this type of renovation project MUST be done by a professional, who will be able to guarantee that the foundations will not be made more fragile. They will calculate the new structure’s resistance level, as well as determine which steps will be necessary to avoid causing problems with the building’s structure. 

Among other things, they will recommend installing new foundation walls below the house to create a better weight distribution, in addition to making it possible to build a space that is the same size as the ground floor.

They will also advise that you cover the basement walls using a special membrane that drains the walls, preventing future water ingress situations. Increasing the size of your house works on two levels: you’re creating more living space whilst adding extra value to your house, which will be reflected in the sales price.


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