This big blog on building bathrooms is coming to you from the floor of The Remodeling Show where I am delivering several demonstrations on (can you believe it) building bathrooms. Among the many topics I’ll hit–everything from how to deal with Swiss-Cheesed floor framing (a perennial old house challenge) to the differences between minimum code requirements and minimum design recommendations and insulation tips–I’ll also address a simple-ish way to upgrade a bathtub, add elegance, and still retain the feel and finishes required for weaving a modern bathroom into an old space.
The design trick is simple: A raised bathtub. Execution may prove challenging because you have to deal with the floor system. Raising our new tub enabled us to relocate it in the small room and decreased framing headaches.
Planning: What to Look for When You Move a Bathtub
Before and after you finish demo work, you’ll need to plan and check the plans you made. For the bathtub, you need to plan the drain’s route to the soil stack. The straighter the path, the easier it is. If you have to go through a joist there are several ways to address it depending on site conditions. Sometimes I eliminate the joist where the drain pipe will go through and transfer the load to the joists on either side of it by building two headers on either side of the pipe (if you know how a skylight is headed off, this is the same technique) and securing it to the remaining joists metal connectors.
Some contractors use a steel bracket made by MetWood that reinforces the wood after you cut a 4½-inch hole through the middle of it allowing you to leave the joist in place. There are a zillion other iterations, but here’s the main take-away: do not compromise the floor framing. Drilling a hole for a drain pipe, to be clear, is compromising the floor framing. Doing it through several joists goes beyond compromise to deal with the devil.
Framing: Getting the Structure Ready for the Bathtub
Once you’ve determined the floor framing is suitable to support the tub and you know where to daylight the plumbing, the rest is pretty basic and the pay-off is terrific.
It depends on if your floor is open and what it’s framed with if you should add blocking and metal connectors (joist hangers) between the joists. Check on this with your local building inspector. This goes back to the italics above: a tub full of water and a person (or people) is not exactly light. If you’re simply raising a tub that’s already there, you should be OK.
To support the tub along the wall we nailed a ledger–a 2×4 on edge–across the wall studs. Then we built what amounts to three very small stud-walls for the other three sides. We ran 2×4 “joists” from the ledger to the wall, then we decked it with ¾ inch plywood.
Once the pedestal is in place, frame the stud walls for the tub enclosure on top, specific directions for which should come with the tub you purchase. Next phase, adding trim.