If you are looking to add extra space to your home by lowering your basement , the Addison construction team can provide you with a free on Site Consultation and then prepare the building permit drawings that you may need for your project.

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What is Underpinning?

Foundation underpinning is a repair process that strengthens foundations that have been weakened though a variety of factors. In the process of underpinning, the area underneath the load of the foundation is repaired or reinforced for a safer, more stable base.

Underpinning Methods

Underpinning the foundation walls: In this method, a staged sequence of holes are dug-out from under the footing of your home. (The footing is the concrete or brick pad which spreads the load of the foundation walls onto the soil.) Typically, a 3′ wide holes, separated by at least 6′ of undisturbed soil, is prepared and filled with concrete. Once the first stage of underpinning segments are complete, then the adjacent 3′ wide segments are dug-out, and the underpinning process is repeated. Here, the idea is that you first extend the footing of the house to a lower level, after which you can safely dig-out the soil from the inside of the basement, without undermining the foundation walls of the house.

Benching: In this method, a stable soil slope usually not exceeding 7V:10H is maintained between the sub-grade under the lowered basement floor level, and the underside of the original footings (to avoid undermining the footings). Then, a steel reinforced concrete “bench” is poured over top of the stable soil slope and footing, to ensure that the soil slope is protected. This process is less expensive than underpinning, however it leaves you with a concrete bench around the interior perimeter of the basement, which will decrease the square footage of your basement.


Our team will conduct a site visit and engage an architect and structural engineer to prepare drawings for the permit application process. The documentation will include all specific measurements and construction process specifics that will be carried out during the construction phase.


The underpinning of a basement can be completed between 4-6 weeks. However our team will have to conduct a site visit in order to understand the exact scope of the projects circumstances , as sometimes there can be an unforeseen issue along the way especially for older houses.


Do not hesitate to contact us with any questions regarding our services, or if you want to discuss your project and discover how we can ensure its success!

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