Are You Feeling Lucky? (Construction by Dummies – Headers)
In our continuing series of Construction by Dummies, we discuss headers for timber framing, specifically the members that frame around an opening through a floor or roof.
Openings are often necessary through a floor or roof for the penetration of a stairway, a chimney, a dumb waiter, a dormer, etc. Headers provide support around the opening for the plywood or OSB deck. Headers are necessary at the edge of the opening to provide support for the weight of the deck, the floor or roof coverings on the deck, other building components on the deck, foot traffic, etc. Support prevents excessive movement of the deck, usually sagging, at the edge of the opening and reduces the risk of separation and/or damage to those building components installed to seal the transition between the deck and vertical surface of the penetrating component (stairway, chimney, dormer, etc.).
In the above featured photograph notice that there are no lumber members that frame along the edge of the opening around the chimney. Since the OSB deck extends only a short distance between the truss and the chimney, there may be little movement and the risk of separation and/or damage may be reduced, but it is not eliminated. It appears that the opening was cut and the chimney installed after the trusses and deck were installed. There was no apparent plan for a roof deck opening for the chimney by the carpenter.
Perhaps this chimney was a retrofit addition: but even then, headers should have been added. Like most poor construction practices, we see that this works for a while. But, how long is “a while?”
As Dirty Harry Callahan would say, “Are you feeling lucky?”