Article and photos by Gregory Havel
Firefighters know from experience that overhaul is strenuous work. Some materials (drywall board and plaster, especially when they have been exposed to heat) can be easily removed from the structure to expose concealed void spaces that can contain fire. Other materials (plaster on expanded metal lath, tin ceilings, tongue-and-groove paneling, board ceilings, impact-resistant drywall board) are more difficult to remove.
As interior design and architectural standards change, interior building finishes change, as do the ways that they are attached. Up until about 50 years ago, most interior finishes were attached with nails: wood lath, expanded metal lath, board ceilings, wainscoting, drywall board, paneling, and tin ceilings. When pulled with a pike pole, the nails either pull out of the building frame, or pull through the material that they held.
Nowadays, screws are as common as nails in wood frame construction, and are the preferred fastener in some applications, including drywall board and board ceilings. Screws are more difficult to pull out of the wood framing members than nails. Screws used to attach drywall board and sheets of interior sheathing have larger heads than the nails that were formerly used. Trim screws (for board ceilings, wainscoting, and other purposes) have smaller heads than drywall screws, but larger heads than finishing or casing nails. Generally, materials attached with screws are more secure than if attached with nails. This is good for the owner of the building, but more difficult for a firefighter assigned to overhaul.
Some new and remodeled homes are again using the board paneling and ceilings that were popular a hundred years ago. In those days, furring strips were usually nailed horizontally across the studs to attach the wall paneling boards. Ceiling boards were often nailed directly to the ceiling joists. Photo 1 shows hardwood ceiling boards screwed to the underside of ceiling joists (August 2008). Today, the architect or interior designer often specifies a half-inch or 5/8-inch plywood backing, screwed directly to the studs, ceiling joists, or trusses (photo 2). The wall or ceiling boards are then screwed or nailed to the plywood. These boards usually have tongue-and-groove joints, and the trim screws or nails are driven at an angle through the tongue and the edge of the board into the plywood. When the next board is in place, the fasteners are concealed. Photo 3 shows another room in the same house with the preprimed wall and ceiling boards in place and ready for painting.
Pulling the ceiling shown in photo 1 will be very difficult. Do not attempt unless there is a need for it. Use a thermal-imaging camera to check the walls and ceiling for hot spots. Remove the recessed “can light” fixtures and use the openings for inspection holes, and as a starting point to pull the ceiling if necessary.
Pulling the ceiling or walls shown in photo 2 and photo 3 will be nearly impossible. Use a thermal-imaging camera to check for hot spots. Use a battery-powered circular saw to cut inspection holes that can be expanded for fire attack, or used as starting points for removing the ceiling with power tools.
Although a carbide-tipped chain saw might cut faster than a battery-powered circular saw, this is a high-risk operation. Using a chain saw above shoulder level is always dangerous; more so when making plunge cuts; and even more so when working from a ladder or stepladder. Although a chain saw cuts faster, it is also possible to cut through the bottom chords of wood trusses and cause the collapse of the structure above. It is also possible that the atmosphere during overhaul may be oxygen-deficient and stall the saw motor.
