How to Build a Flat Ventilation Roof Prop

Prop Materials

• A flat roof ventilation prop teaches firefighters how to use their power saws for cutting ventilation holes through flat roofs to let deadly smoke, fumes and heat escape from a burning building. A basic flat roof ventilation prop requires four, 16-foot-long 2-by-10-inch framing boards; four, 8-foot-long 2-by-10-inch framing boards; eight, 8-foot long 2-by-6-inch joists; and eight, 8-foot-long 2-by-4-inch joists. You also will need four, 4-by-8-foot sheets of 3/4-inch plywood, 16 joist hangers for 2-by-10-inch joists, plus four sections of old telephone pole or similar heavy lumber roughly 6 feet long. You also will need enough nails to hold the pieces together.

Construction

• Lay out an 8-by-16-foot rectangle and bury the telephone poles 3 feet deep at each corner. Notch the exposed 3 feet of the poles to support the 8 foot framing boards of each short side. Nail the long and short two-by-tens together to form double boards and set the short boards into the notches on the phone pole supports. Nail the long framing boards to each end of the short framing boards. Install joist hangers 20 inches apart along the inside of each of the long sides of the frame. Set the 2-by-6 joists into each pair of hangers and fasten them securely into place.

Sacrificial Top

• The next step is to install the pieces that will be sacrificed during training sessions. Install a two-by-four on top of each 2-by-6 joist and fasten it separately. These two-by-fours can be easily and cheaply replaced if they get cut up during training exercises. Top the frame with the four plywood sheets. Securely fasten the plywood sheet at each end and paint each end sheet with a non-skid deck paint. Leave the two sheets at the center unpainted. Fasten them lightly. These center sheets will be cut up during training sessions and replaced when the session is over. The painted outer sheets form the no-cut zone.

Super Simple Prop

• If your fire department has access to old pallets and scrap plywood sheets, you can build a super simple, super cheap, disposable flat roof ventilation prop. Obtain eight identical wooden shipping pallets and a bunch of scrap plywood sheets. Pick a flat, level surface. Stack the pallets 2 feet high and fasten them together. Assemble the pallet stacks to form a square. Fasten them together. Cover the pallets with the scrap plywood sheets and fasten the sheets to the pallets. Once this prop is chewed through, you can throw it away and build another one.