Running the Floors

With the foundations backfilled, it was finally time to start framing. The lumber arrived, along with snow—par for the course for Flagstaff in late May. First step was getting the treated sill plates down over foam gaskets, bolted down tight. For framing, we went with 2x10s to match existing house floor framing, at 16” on center. On the house, the ledgers are bolted to existing rim joists, while the north addition is framed conventionally, with the 2x10 rim joist on top of sill plate.

But because of a rising grade, the east addition was framed with the joists resting on a “reverse brick ledge” to the inside, which gives the joists a solid 4 inches of waterproofed concrete to protect them from the earthen grade. Owens Construction's Bill Owens chose to do solid blocking in about 18 inches from the foundation instead of a rim joist on this one, specifically to allow better access to the rim for insulation.

With the joists in place, it was time to unbundle Huber's AdvanTech ¾” subfloor, one of Owens' favorite products. “This is clearly a premium product,” he says. “It has waterproof resin all the way through and has a 500-day no-sanding guarantee. I also like how the tongues and grooves are precision milled, and it goes together smoothly."

This was not the first time Owens had used the proprietary subfloor adhesive gel offered by AdvanTech. “We use this all the time back in Ohio. One thing that impresses me is that it can be used in the wet, cold, and even freezing weather with no loss of bonding performance”, said Owens. “That can be a real advantage for winter construction, or spring construction in the high country.”