Hi all,
I’m remodelling an original bump out on a 1930 bungalow. It is 10′ 6″ wide by 6′ deep, fully enclosed with a concrete crawl space beneath and the stairwell for the basement access. The floor joists are 2 x 6 (good old days: 1-5/8″ x 5-5/8″) 18″ on center and run the width, so 10′ 2″ long, uninsulated. Power was supplied by BX tacked to the bottom of the joists.

Three fouths of the bump out width will become living space, and the floor is a little springy for that use. It’s not terrible and could be left alone, but it could be better. The concrete wall of the basement stairwell would be an adequate foundation for a cross-brace under the floor joists. A pair of 2x6s as a beam across the bottom of the joists, supported by jack studs to the stairwell wall at one end and the foundation wall at the other. The stairwell wall is 4′ 6″ from the outside wall of the living space, or said another way, directly under the middle of the living space. I could instead plane the bottoms of the joists and glue another 2″ of 2x lumber to the bottom. Way more work, but probably a stiffer floor and would leave better storage access in the crawl space.

In any case, the old BX needs to be replaced with conduit. I need to insulate under the floor, and the insulation must be covered by plywood screwed to the bottom of the floor joists. I don’t see an easy way to run the conduit below the plywood cover, so passing the conduit through the centers of the joists seems the best way, but makes access for future additions much harder.

Thanks for taking the time,

Scott