Crawl Spaces

We have two crawl spaces under the additions to the main house, which were built in the late 1960′s. The original house has a full basement, which is nice because it is a good place to locate heating equipment, the oil tank, the hot water tank, the well tank, etc. Some of our friends live in an older house where there is just a 4 foot crawl space under the entire house. They found it very inconvenient when they need to have their water softener installed.

New opening to crawl spaceWhen the project began, we had access issues with both crawl spaces. The south addition, which was the first addition to the house, had a four foot crawl space. The only access to that space was through a small hatch outside. This is the reason the home inspector missed all the termite damage, because he “couldn’t get in there.” The cinder blocks in the foundation wall near the access hatch were crumbling apart. The floor was dirt covered with green mold. Floor support structure was eaten away and needed to be replaced.
Repaired cinderblock wallThis is a list of things which was done to the south addition:

First we opened two 3 foot by 4 foot access holes through the basement wall into the crawl space. We stayed at least 3 to 4 feet away from the corners of the basement so they would not be weakened.

We sprayed the floor with a weak bleach and water solution (about 1/4 cup of bleach per 1 gallon water to kill the mold.

I installed a dehumidifier to keep the air as dry as possible. This had made a huge difference. Instead of empting the water catch pan everyday, I ran a drain hose to one of the floor drains. I think I get about 1/2 gallon of water a day from the dehumidifier.

The flooring system was removed; girder, joists, plywood floor, and everything else, so that there was one large hole inside the house. The contractor dug out and poured new support pads for the new lolly columns.

The outside shell of the house was jacked up and the crumbling cinder block wall on the east side was replaced. This is just below the French door in what is now the kitchen area.

The rest of the outside shell was jacked up and the entire sill plate and box was replaced.

Replaced the girder, joists, subfloor.

Covered the entire dirt floor with thick plastic sheeting to keep out moisture.

After all that, we were ready to construct the walls for the washer/dryer room, the pantry and the living room closet.

Low crawl spaceIn the east addition, we faced many of the same problems except there the crawl space was barely deep enought for the floor joists. In this space, the work was done from the top.

The entire floor system was removed.

We removed 52 wheel barrow loads of dirt from inside the house to get the crawl space floor low enough to at least crawl through. I believe there is about 18 inches of clearance, which means I can now belly crawl in, then roll over to work on something.

The contractor jacked up the outside shell, replaced the sill plate and box

The wall was insulated with 2 inch ridgid foam insulation. Something I want to do to the rest of the house

A thick plastic sheet was put over the dirt floor.

The girder, joists, subfloor were replaced .

Crawl SpaceFinally, we were back to a renovation vs. major repair.Things that I would do differently today. Instead of the thick sheet of plastic, I think a scratch coat of concrete would be better. It would have been easier to sweep up after drilling all of the holes to run the electrical and plumbing work. Also, in a couple of areas, I have
managed to poke a few holes through the plastic with a dropped hammer, drill or other tool. The plastic is just not as sturdy as I thought it would be.