Sister Beams  Reinforce a Sagging Ceiling

by Patrick Ropp—GBI Technical Advisor

Above: The sister beams reinforce the failing ceiling beam to easily carry the load, with capacity to scare. Rebar is embedded into the bottom surface of the sister beams where the tensile load is at its maximum. (Figure 6)

While working in my shop/converted (never to be seen by a car) garage, I noticed that the double 2×8 beam supporting my ceiling joists was sagging about 2 to 3 inches in the middle. The builder of this forty-year-old garage didn’t use full-length 2×8’s to span the 19′ width, but four 2 x 8’s nailed together with staggered butt joints. Over the years, gravity took its toll. The nail holes elongated, the butt joints opened up, and the beam sagged ominously. Continue reading →