Extending A Basement’s Foundation.

If you have read some of my previous posts you know that I am in the process of increasing the depth of the basement of a townhome that I purchased. The original height of the basement was around 7 feet, and my goal is to increase that to around 8 feet. To do this I needed to remove the original floor and to excavate several more feet of earth. The additional depth is necessary to accommodate the floor’s gravel base and other floor structures.

This has been an arduous process which is chronicled in previous posts. Naturally, the original foundation and its footings did not extend to the new depth and I needed to extend them to insure the structural integrity of both the basement, and the home’s living space.

I believe that the best way to show this process is to use a series of photos that demonstrates the steps involved. Please see the images below.

I partially constructed the concrete forms, which were then passed through the basement window. The forms were 24 feet in length. I used this long length as I wanted the forms to be as strong as possible. In retrospect, I would have shortened the forms to 8-foot units as it was very difficult to remove them once the concrete had cured.
Using a grinder I precut and shaped the rebar that would be used to strengthen the concrete.
I fitted my Bobcat with a scoop which allowed easy movement of the concrete from the concrete truck to the back of the townhome. I used a total of about 8 yards of concrete or one full truck.
Concrete was transferred from the Bobcat to the basement via a shoot placed in a basement window.
A crew in the basement moved the concrete from the window to the concrete forms. You can see the completed forms in this photo.
A worker tilting a wheelbarrow full of concrete into a form. Another worker can be seen spreading out the concrete evenly in the form.
After the concrete had cured we had to manually remove the forms. I wish I would have made the forms in smaller units, but I also wanted them to be as strong as possible.
Here you can see the foundation extension complete with new footings.
In this photo, you can see me standing on a small fragment of the old foundation. I can easily touch the joists.
This photo gives you an idea of how deep we had to excavate the basement floor. I can no longer touch the ceiling.
Naturally, I had to also remove this little island of concrete which supports the vertical support post.
The vertical support post and the island of concrete have been removed and a new concrete pad placed. These temporary support posts will be soon be replaced by a permanent one. Note that the gravel base has been evened out in preparation for the new concrete floor. That post to follow.