Postwar Tract Bathrooms in Mountain View

According to the Census Bureau’s American Community Survey, 15.3 percent of Mountain View’s housing was built in the 1950s and 17.5 percent in the 1960s. Just under a third of the city, put up across two decades, largely by the same methods to serve the same expanding employers. Add the 1970s and more than half the housing here predates 1980.

Uniform construction has an underrated benefit for a homeowner: the problems are predictable. Walk into a 1958 Mountain View tract house and you can guess most of what the bathroom will turn out to be before opening a wall.

The pattern

A single hall bathroom, roughly 35 to 55 square feet. A tub and shower combination against one wall, which is the wet wall carrying the supply and drain lines. A single vanity opposite, usually 30 or 36 inches. A window over the tub or nothing at all. One light fitting in the middle of the ceiling, and often no exhaust fan whatsoever. Underneath it, a concrete slab.

That layout was efficient to build and it has aged in specific ways.

What has aged badly

The supply lines. Houses from this period were commonly plumbed in galvanised steel, which corrodes from the inside out. The pipe narrows over decades, flow drops, water discolours after the system has stood, and eventually a joint fails. If a house still has galvanised supply in service, a bathroom remodel is the cheapest opportunity it will ever have to replace it, because the walls are open anyway. Doing it as a standalone job later costs multiples.

The ventilation. Many of these bathrooms were built with no mechanical exhaust at all, on the assumption that a window would do. It does not, which is why current code requires a fan ducted to outside air regardless of whether there is a window. Decades of unventilated showering is also the usual explanation for the paint condition, the swollen door frame and whatever is happening at the base of the wall behind the tub.

The electrics. Ground fault protection did not exist in residential bathrooms when these houses were wired. Neither did the assumption that anyone would want more than one outlet. Current requirements in Mountain View call for protected receptacles within three feet of each basin on a dedicated 20 amp circuit, which usually means a new circuit run rather than an upgrade to an existing one.

The waterproofing. Tub surrounds of this era were commonly mortar bed over wire lath, which was a decent method, or tile directly on gypsum board, which was not. Where a shower has been leaking slowly for years, the evidence turns up in the subfloor and the framing at the wet wall, and it is one of the more common reasons a project grows after demolition.

What has aged fine

The framing, generally. The layouts, more often than people expect. And the fact that everything sits on one level with a straightforward roof means these are simple houses to work in compared with almost anything built on a hillside.

What it costs to put right

A shower conversion with a new vanity, new floor, proper ventilation and updated electrics in one of these bathrooms runs $18,000 to $30,000 and three to six weeks of construction. A full gut, which is the same work plus new supply lines, new substrate throughout and a reworked layout, runs $30,000 to $65,000 and eight to twelve weeks.

The jump between those two numbers is mostly about whether the fixtures move. On a slab they cannot move cheaply: relocating a drain means cutting concrete at roughly $1,500 to $4,000 per fixture. Which is why the most valuable early conversation about one of these bathrooms is not about tile, it is about whether the existing layout is wrong or merely tired.

Often it is merely tired. A 40 square foot room with the tub on the wet wall and the vanity opposite is not a bad plan, it is the plan that fits. A pocket door, a wall-hung vanity, large-format tile and light that comes from beside the mirror rather than above it will transform how that room feels without a single fixture moving.

Before demolition

Two checks are worth making in any house of this vintage. First, asbestos and lead testing, since sheet flooring, the mastic under it, joint compound and paint are all candidates in a pre-1978 house. Second, whether the supply lines are galvanised, which a plumber can establish in minutes and which changes the shape of the whole budget.

Both are cheap to find out beforehand and expensive to discover halfway through.

For the layout side of this, see the small bathroom layout guide. For the concrete, the slab plumbing guide.