Bath renovation tips

By Mike McClintock, Special to Tribune Newspapers

Bathrooms are not much over 10 percent of the floor space in typical homes. But per square foot, they’re often the most expensive due to all the plumbing, fixtures and finishes like tile instead of drywall. That goes for remodeling, too, where estimates for updates cause sticker shock.

Bigger footprint

There are two ways to get one: build an addition, or steal space from an adjoining room. With minimal framing, trade an adjacent walk-in closet for a sauna or whirlpool tub. Reframe a long clothes closet, and double sinks can recess into the area freeing up bathroom floor space. Partial reframing can make a big change, but save time and money by leaving most of the room intact.

Adding space from scratch, though, amounts to a small slice of the full home-building process from excavating to roofing. You need plans, permits, concrete, framing, the works. The investment can pay off handsomely if the old-fashioned, one-person space becomes a modern master bath with walking-around room. Gutting also allows major improvements like radiant floor heating, and vent systems that deal with moisture automatically. But it’s not worth the disruptive and expensive project to gain only a few feet.

The exception is a bump-out. Floor framing is strengthened by doubling joists or changing 16- to 12-inch centers, or both, and extended to cantilever beyond the foundation, say, by the depth of a sink counter. This increases floor space without changing the foundation footprint. But the front and both sides of a bump out become exterior walls — not the best place for plumbing. Consider upgrading the protection against frozen pipes by using 2-by-6 wall framing with room for more insulation, and adding insulating foam board under siding as well.

Modern mechanicals

Remember that moving fixtures means moving plumbing. Water lines are not a big problem, specially with a flexible PEX system that requires no fittings to turn corners. Drains and their vents need more effort, like opening up the floor. Among other glitches, drain lines for older toilets flushed with more water and could carry away waste at a modest slope. Replace one with a code-mandated low-volume unit, and it may not clear waste without multiple flushes, defeating the water-saving purpose unless you re-plumb the drain with a greater slope. Low volume sounds very green — until you have to use twice as much water to make it work.

Existing ductwork for heating and cooling can usually handle a small increase in square footage like claiming a closet from the next room. If HVAC estimates show the capacity a bit shy of the new space, consider an electric heater. It might be a toe space unit under a vanity, or built into an overhead fan, enough to bridge the gap.

A contractor may also be able to steal some supply from another room with a diverter — an in-duct baffle that directs more air to the larger bath space. But when the remodel is more than a bump-out — half again as large or more — the original supply will have to be upgraded.

In a bath built mid-1990s or so, an electrician may have to pull new lines and upgrade circuits to handle more lights, more outlets, a more powerful vent fan, assuming your existing service panel has the capacity. If not, it can be several thousand more to upgrade the panel. Even on a small redo, an electrician will need to meet code with GFCIs (ground fault circuit interrupters), a quick-tripping type of outlet. In some areas, inspectors also want the protection of AFCIs (arc fault circuit interrupters.)

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