How to Build a Fireproof Crawlspace Door

Maintaining the integrity of a firewall is an important element of home safety. In some older homes, the access to the crawl space under the house is in the garage. In others, an attic crawl space can be accessed in a hall or bedroom closet. If that firewall between the house and garage or attic is inadequate or breached, a fire can spread rapidly throughout the house. While no door is 100 percent fireproof, constructing a fire-resistant door for the crawl space is essential to increasing the safety of your home.

Tape measure
Solid wood door, 1 1/2-inch thick
Carpenter's square
Saw
Electric drill with screwdriver bit
Steel hinges
Fire-rated intumescent door gasket
Steel latch

Instructions

- 1
  Measure the height and width of the crawlspace opening. The minimum size of a crawlspace opening is 18-by-24 inches. If the heating and air conditioning system is in the crawlspace, the minimum size of the opening is 30-by-30 inches.
- 2
  Subtract a quarter-inch from the crawlspace opening's measurements. This allows for an eighth of an inch clearance around the door.
- 3
  Mark the crawlspace measurements on the solid wood door. Check the opening and the door with a carpenter's square to ensure the door will fit. Don't assume the opening is square.
- 4
  Cut the door to size with a table or circular saw.
- 5
  Install steel hinges on the door.
- 6
  Attach a fire-rated intumescent gasket around the door opening according to the manufacturer's instructions. This gasket will expand in a fire, preventing gases and flames from entering or leaving the crawl space.
- 7
  Mark the location of the hinges on the door frame. Predrill the screw holes, then attach the door hinges to the frame. Add a steel latch to finish the installation.

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