Rejiggering the Joists

Fortunately for Tom Silva, the downstairs has enough ceiling height to accommodate the 9-inch loss needed to lower the second floor. Plus, in a barn with exposed framing, lowering the joists is straightforward; with no plaster and lath to rip out or plumbing to worry about, Tom can simply install new joists below the old ones, tying them into new rim joists he's bolted to the wall framing. Then, with all the new joists in, he can simply pull up the existing hayloft floor and remove the old joists from above before laying the new flooring. With the second-floor ceiling at the new height of 7½ feet, and the first floor now at 8 feet, "both are perfectly usable," says Tom.

Tom uses engineered I-joists, which are made of composite wood, interspersed with joists made from laminated veneer lumber (LVLs), a form of plywood made to the dimensions of standard 2x framing lumber. This gives the floor strength across the span of the barn without requiring any interior load-bearing walls. "I couldn't make that span with standard 2x12 lumber," says Tom. "I could use a 2x14, but I'd have no flexibility to cut holes. When it came time to run plumbing, I'd be dead in the water."

I-joists, by contrast, are not structurally compromised by holes — even large holes for drainpipes and small ductwork — as long as they are positioned according to the lumber manufacturer's specifications. As a result, systems that might otherwise need to go into chase walls can be tucked into the ceiling. And because they are so stable and rigid, I-joists make for one tight floor. "The code says this floor can bounce half an inch when I'm walking on it," says Tom, as he moves across the new attic floor. "That's good enough for code, but it's not good enough for me. I'd be surprised if we even had an eighth-of-an-inch bounce — just enough to be flexible."

Ask TOH users about Home & Real Estate

Contribute to This Story Below