How do I Build a Full Basement in an Existing Crawlspace?

Convert a Crawlspace Into a Basement

• 1

  Contact your utility companies prior to converting your crawlspace. Find out the location of any pipes and wires to avoid damaging them during construction.

• 2

  Inspect the existing foundation walls thoroughly. Pay special attention to areas with cracked concrete or cinder blocks. Crawl under the existing home to perform a thorough visual inspection of the floor joists and supports. Add additional supports to any compromised areas.

• 3

  Remove the existing crawlspace floor by breaking it up. Use a sledgehammer or jackhammer if necessary. Use a wheelbarrow to wheel out the broken pieces.

• 4

  Use a shovel to begin removing dirt from the crawlspace floor. Wheel out the dirt with a wheelbarrow. Start near a support post and dig down until you reach the correct depth for your basement.

• 5

  Prepare a footing by digging a 3-foot-by-3-foot hole 4 inches lower than the depth of the basement. Place an adjustable support post into the footing hole. Extend the support post until it rests tightly against the ceiling. Pour a footing around the steel support by filling in the 3-foot-by-3-foot hole with concrete. A new support pole must be installed where each existing support is located.

• 6

  Dig the hole to fit the parameter of the house. Dig down 4 inches lower than the depth of the basement. To prevent the dirt under the foundation from caving in, do not dig closer than 2 feet from any existing foundation walls. Level off the floor and pack down the dirt at best you can.

• 7

  Pour a concrete floor 4 inches thick. Level and smooth the floor using trowels. Allow the concrete to cure for 48 to 72 hours.

• 8

  Construct new walls under each existing wall using concrete blocks. Use mortar between the blocks to hold the blocks in place. Build each wall up to the basement ceiling.