How to Check a Subspace Under an Addition

Conditioned Subspace

• 1

  Find the access point for the crawlspace. For a conditioned space, this is typically through the floor in the room above. Access hatches can be hidden under carpets, furniture or appliances.

• 2

  Turn on the flashlight and crawl into the subspace. Look for the supply vents from the furnace and feel if they are delivering air to the space. Look for a return vent in the room and place a tissue against it to see if it is pulling air back to the furnace.

• 3

  Look closely at the condition of the wood. Probe various areas around the floor joints with the carpenters awl. If the awl penetrates the wood deeply, it maybe caused by rot.

• 4

  Look at the underside of the floor sheathing for signs of water leakage from above. Water stains appear as dark rings in the wood.

• 5

  Inspect the insulation around the walls of the space for uniformity. Check that the subspace has a concrete floor. A dirt floor in a conditioned space brings unwanted moisture into the building and creates a environment for mold to grow.

• 6

  Look at the condition of the plumbing running through the space for signs of leakage or damage.

Unconditioned Subspace

• 7

  Find the access point for the subspace. For an unconditioned space, this is typically on the outside of the building in the space between the first floor and the grade.

• 8

  Turn on the flashlight and crawl into the space. Look for vents on the side of the space to bring fresh air in and out of the area. There should be vents on two opposing sides of the subspace.

• 9

  Look at the condition of the insulation fastened between the floor joints. It should be tightly connected together and have uniform coverage. It is typically secured in place with chicken wire stapled to the bottom of the joists.

• 10

  Check that there is no plumbing being run through the space if your climate experiences freezing temperatures.

• 11

  Look at the concrete foundation walls for large cracks. Horizontal cracking is the biggest concern for foundations.