To Strap or Not to Strap: a Ceiling Question
Tom Silva explains the tradition and function of strapping
On many TOH TV projects, I see what appear to be -inch furring strips nailed to the underside of ceiling joists before the drywall goes up. Is this an East Coast thing? Here in the West, drywall is screwed directly to the joists. What’s the reason for adding these strips?
—Dale Campbell, Royal Oaks, CA
Here in New England, we call those 1x3 strips “strapping.” Their use goes back many years, to the days when lumber widths weren’t standardized. Builders nailed strapping perpendicular to the underside of joists as a way to bridge those differences and make their ceilings flat. Nowadays, lumber sizes are much more consistent, and most builders throughout the country have no problem simply screwing drywall directly to the underside of joists and rafters. That way does take less time and use less material, but the tradition of strapping ceilings still remains strong among builders in parts of New England, for the following reasons.
Strapping creates a narrow space to run electric wires and supply pipes perpendicular to the joists, which makes life easier for plumbers, electricians, and remodeling-minded homeowners. It adds stiffness to the floor or roof framing. It supports drywall seams better because the face of a 1x3 is much wider than the edge of a 2x, so there’s less chance of the screws missing the wood or crumbling the drywall. And, as in the old days, strapping in combination with shims makes it possible to flatten sagging or uneven ceilings.
Strapping can actually save money when joist spacing exceeds 16 inches on center. If you fastened drywall directly to studs that far apart, you’d have to use heavier, more expensive 5⁄8-inch sheets. But if there’s strapping set on 16-inch centers, then lighter, less expensive ½-inch sheets would be okay.
Now that you brought it up, I wonder why builders everywhere don’t regularly use strapping the way we do.