Lowering the Cellar Three Feet

In order to maximize the living space we decided to turn the cellar into a useable space. To do this we cut a 10×10 foot hole into the floor of the basement, which is only technically called the basement since it is a foot below grade. Practically it is the garden level. Once a hole was in the south side of the garden level it allowed plenty of sunshine to pass into the cellar.

The only problem is that the cellar was only six foot high. So we have dug it out another three feet. We had to dig under the existing foundation, which can be risky if not done correctly. First we built a second inner wall out of cinder blocks in the entire cellar. The existing brick wall was so deteriorated you could pull the bricks out by hand and it was actually amazing the four floors above kept standing.

The cinder block wall only took up four inches but added all the strength we needed to support the house, which we were in the process of banging and shaking to no end. We then dug down three feet in small areas at a time and underpinned the wall with concrete and the rocks we found in the soil.

Before putting the concrete we put plastic vapor barrier and two inches of waterproof insulation to guarantee a warm and dry environment.

Above you see the sections being dug out.

Above is the vapor barrier, called Stego wrap. It is one of the few plastics that actually do stop moisture and is priced accordingly. Most cheaper brands don’t actually stop moisture.

Here we are putting the plastic, insulation and making the form to pour the concrete and stones.

We used XEPS or extruded polystyrene, which is a dense and waterproof insulation. It is also not friendly to termites, which is important in this area.

Here you can see the rogh finished product where the floor had been dug out and the underpinning poured. We will then pour the concrete floor and then build the cinder blocks up to the other cinder block wall that is currently hanging three feet above ground.

Here you can see the opening in the floor above. We have also knocked out the south wall for a wall of windows so the sun can really shine down into the space. On the front and back walls we did not put cinder blocks because those walls had good solid stone as you can see in the picture. You can see the concrete underpinning under the stone walls where we dug down. A worker is finishing off some underpinning but using cinder blocks instead of concrete since that little alcove is not holding up the building and does not to be as strong.

This photo shows the cellar before dug down. As you can see there was little headroom.

Here you see the same cellar almost all dug out.

About the author: Gennaro Brooks-Church

5 comments to “Lowering the Cellar Three Feet”

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  1. dapluma - January 30, 2009 at 7:36 am

    sorry to hear about that. digging is always dangerous and we will be carefull. osha rules at all times is the way we run our buisness and my homes no exception. thanksfor the heads up. dapluma

  2. Gennaro Brooks-Church - January 27, 2009 at 10:45 am

    Just be sure you are careful. Two guys just died recently in the neighborhood while underpinning. The contractor didn’t support a weak wall and it collapsed onto the workers.

    Only do in small sections and strengthen any weak walls with pointing and/or stucco with wire. At the very least.

  3. dapluma - January 27, 2009 at 9:44 am

    Thanks guys! Now that Ive seen an actual underpinning I can do my own. That crawl space was really a waste off space. I think Ill go with an 18″ t shaped footer under mine though, since i have cheap stone and rubble walls down there. I would rather eliminate all the existing foundation but the house isn’t worth it . thanks again guys your pictures cleared things up considerably. dave dapluma

  4. Gennaro Brooks-Church - December 14, 2008 at 7:40 pm

    I actually forgot to mention it but there is a footing below the three feet. It comes six inches out from the foundation and is a foot to six inches deep. You can’t see it in any of the pictures because the dirt covered it but you can see the guy building the form for it.

    I used Portland cement with 3/4 inch gravel and sand mix. I also put as many stones into the wall as possible. They are, uh, rock solid.

    The sewer line from the house is exactly level with the new dug out basement, which means the mains are a couple feet lower. I’m not sure how many. Based on road construction I saw on another street in the area they could be as much as sixteen feet under the street level!

    I didn’t put a drain system….it wasn’t specified by the engineer and the earth was so dry I didn’t feel the need for one. It was parched.

    In terms of insulation the whole structure (footing and slab) will have two inches of XEPS foam board. I guess I could do more but I feel that is good enough.

    You plan to move the building is ambitious but definitely sounds like it would have worked.

  5. Vinnie - December 14, 2008 at 6:26 pm

    while one may or may not agree with the method you used to get there the end result is good. However to be code compliant wouldnt you need a new footing for the wall generally approxomately 2-4″ wider on a side plus a new footing drain? Did you use regular grout/concrete or hydralic cement ro there would be no contracting in the wall as it drys?. I had once considered doing something like this to move a building abot 15 ft. My theory was puting a steel frame under the entire building and a c channel facing up in wich to slide it onto a new section of foundation. never did it but gave it some theoretical thought. In the city often the drain system runs under the floor into through large acess holes. Will your basement now be lower than the surrounding sewer system? If it your own building I might have considered putting in a whole new (in sections) insulated form foundation. It would have been very fuel efficent and lent itself to the green theme. And probably been only marginal in extra work except for material removal.

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