The one logical question that every homeowner always asks themselves before undertaking a home improvement project is “Why?” When it comes to basement lowering the answer is twofold. Whether its ceiling height that you’re looking to increase, or you want to turn that impractical basement into a functional space, or you’re looking to move on to bigger things and want to increase your home’s market value – no matter how you look at it, you gain.

More often than not, basement underpinning is carried out at properties with insufficient basement headroom.

The basement underpinning process (known as lowering) is rather complex, but with the right company taking care of the details the work can be done with a minimum amount of disruption to the homeowner.

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There are several steps in the process of underpinning and we handle all of the details during each stage of the project. Before any work actually gets underway, new floor plans and structural modifications must be documented with a new floor plan.

The planning stage must include an engineer and architect. We have access to experienced engineers and architects that will work with you to plan your new space and apply for all of the proper permits to begin the work. Because underpinning requires moving and extending the load bearing walls under the house, having the right permits and municipal approval is a legal necessity.

Please note that no project will be carried out without the required permits and stamped architectural/engineering drawings.


Once the planning stage is completed, and the appropriate permits issued, preparations are made for the actual underpinning job. These preparations include rerouting the connections to your furnace so that heating pipes are out of way. Additionally, temporary support structures, including vertical jacks, have to be installed to ensure the structure of the house remains stable during the basement lowering construction.


The existing concrete floor has to be removed and the soil excavated to a proper elevation. Once that’s done, we are ready to proceed with the underpinning. The perimeter of the basement is divided into sections numbered 1, 2, and 3. First, sections # 1 are dug out, then filled with concrete, a two inch space must be left between the newly poured concrete and the original foundation, then this gap is filled with non-shrink grout. The same procedure is followed for sections # 2 and # 3.

Now that your new foundation walls are in place, old plumbing can be removed, and new plumbing put in its place. You will be provided with new plumbing rough-ins that will enable you to create your desired space. At this point we will install a reliable waterproofing system to make sure your basement stays dry, it consist of internal weeping tiles, waterproofing membrane and sump pump. To get ready for the pouring of the new concrete floor we evenly place four to six inches of gravel throughout the basement. Finally, a new concrete slab is poured. Once the concrete is dry, your new basement is ready to use!


  • Get in touch with Aquamaster Drain Plumbing & Waterproofing Inc. to book a free consultation.
  • We will provide you with an architect/engineer to obtain permits OR you may find one yourself.
  • Architect/engineer will obtain permits and will expedite them according to the client’s timeline.
  • Set the commencement date for the project.

If you are interested in basement underpinning, please do not hesitate to contact us at 416-939-6379

It is a complicated project that must be done properly to prevent damage to the rest of the house. The staff at Aquamaster has helped thousands of customers in Toronto and GTA to lower their basements to turn an unusable crawl space into a beautifully finished room.