What Actually Fits: Six Delco Bathrooms Under 40 Square Feet, Measured and Costed

Most small-bathroom articles show you a finished photo and call it inspiration. That tells you nothing about whether the layout fits your house. We measured six real ProBrothers bathrooms — all under 40 square feet, all in Delaware County and Main Line homes built between 1900 and 1960 — and recorded the floor plan, what we removed to gain space, the fixture sizes that actually worked, and the finished cost. According to our own job records across these six projects, the range ran $14,800 to $31,200, and the single biggest factor in the final number was never the tile — it was which wall could move.

If you own one of these older Delco homes, chances are your only full bath is a 5x7 or 5x8 box carved out of a hallway sometime in the 1950s, wedged between two bedrooms with a chimney chase on one side. You've looked at a hundred Pinterest boards. None of them tell you what your specific joists, your specific stack, and your specific wall will allow. This is a survey, not a gallery. Six measured bathrooms, six real numbers, and a checklist at the end so you can go measure your own.

The Four Things That Actually Decide What Fits

Before any of the six case studies below, it helps to know what we check on site before drawing a single line on a layout. These four constraints show up on nearly every pre-1960 Delco bathroom we've touched, and in our experience they matter more than square footage itself.

• Joist direction. A drain line can usually run parallel to the floor joists without much trouble. Moving it perpendicular means notching or sistering joists, which is why a toilet or tub that "should" move six inches sometimes can't move at all without opening the ceiling below.
• The cast-iron stack. Homes from this era frequently still carry the original cast-iron waste stack. If it's at or past its service life — which, in the field, most of them are by now — any layout change that touches it turns into a full stack replacement, not a simple reroute.
• No existing exhaust vent path. A lot of these hallway baths were built with a window for ventilation and nothing else. Per the International Code Council's residential ventilation requirements, a bathroom without an operable window needs a mechanical exhaust fan vented to the exterior — and in a house with no attic access above the bath, finding that vent run is sometimes the hardest part of the whole project.
• Window-in-the-shower. Surprisingly common in these floor plans: the only window sits exactly where the new shower wants to go. That's not a dealbreaker, but it changes the fixture selection and adds a glass-block or fixed-pane detail that a generic bathroom calculator never prices in.

Every one of the six bathrooms below hit at least two of these four constraints. Here's what we actually did about each one.

Case 1: Media Borough Twin, 5'0" × 7'6" (37.5 sq ft)

This was a textbook 1920s twin hall bath between two bedrooms, original cast-iron tub still in place, a single casement window on the exterior wall. What we removed: a shallow linen closet on the hallway side, which gave us 14 inches of depth we reclaimed for the layout. What fit: a 60-inch alcove tub-to-shower conversion, a 24-inch pedestal sink, and a comfort-height toilet with the standard 12-inch rough-in intact — we didn't move the drain, because the joists ran the wrong direction for a cheap relocation. Finished cost: $18,400, including a full tile surround and a new exhaust fan vented through the existing window header cavity.

Case 2: Swarthmore Foursquare, 5'6" × 7'0" (38.5 sq ft)

A 1915 foursquare with the bathroom stacked directly above the kitchen, which meant the cast-iron stack ran straight down through two floors with no easy access. What we removed: a plaster furring wall that had been added decades earlier to hide old plumbing, recovering 9 inches of width. What fit: a 36-inch neo-angle corner shower (the only shape that worked once the stack location was locked), a 30-inch vanity with a single-bowl sink, and a floor-mounted toilet shifted 4 inches off its original center. Finished cost: $24,900 — higher than Case 1 because the stack had to be inspected and partially sleeved rather than replaced outright, which we only knew after opening the wall.

Case 3: Wallingford Colonial, 5'0" × 8'0" (40 sq ft)

This house had the window-in-the-shower problem described above: a double-hung window sat directly in the footprint any shower enclosure needed. What we removed: nothing structural — the layout stayed in place, but we replaced the operable window with a fixed, obscure-glass unit set in a waterproof frame, which let the shower occupy the full depth of the room. What fit: a 32x60 shower with a glass-block-style fixed window at the back wall, a 24-inch wall-hung sink to keep floor space open, and a standard two-piece toilet. Finished cost: $21,600. The window reframing alone ran close to $3,100 of that total, which a generic bathroom calculator has no line item for.

Case 4: Wayne Rancher, 5'3" × 7'3" (38 sq ft)

A single-story 1958 rancher with an open crawlspace below — the one case here where access actually worked in our favor. What we removed: a built-in medicine cabinet nook that stole 6 inches of wall depth. What fit: a 60-inch soaking tub (the owners specifically wanted a tub, not a shower conversion), a 28-inch single-bowl vanity, and we were able to relocate the toilet drain 8 inches because the crawlspace gave us clean access from below without opening a finished ceiling. Finished cost: $16,200 — the lowest of the six, almost entirely because crawlspace access meant the plumbing work took roughly a third of the labor hours it took on the two-story cases.

Case 5: Haverford Twin, 5'0" × 7'0" (35 sq ft)

The smallest footprint in this set, in a 1910 twin with a shared party wall and zero attic access above the bath. What we removed: a chimney chase that had been dead since a prior owner converted to gas heat decades earlier — demolishing the dead chase gained 11 inches. What fit: a 30x60 shower, an 18-inch corner sink, and a round-bowl toilet chosen specifically for its shorter 24-inch footprint, which mattered in a room this tight. Mechanical exhaust was the hard part: with no attic access, we ran the duct horizontally through a soffit built along the hallway ceiling rather than vertically, which the ICC ventilation requirement allows as long as the exterior termination point is correct. Finished cost: $19,800.

Case 6: Rose Valley Cottage, 5'6" × 6'6" (35.75 sq ft)

A stone cottage from the 1930s, the only one of the six where the cast-iron stack genuinely had to be replaced in full rather than reused. What we removed: part of a closet from the adjoining bedroom, borrowing 10 inches to square off an awkward angled wall. What fit: a 32-inch quadrant shower, a 24-inch pedestal sink, and a comfort-height toilet. The full stack replacement — running from this bathroom down through a finished basement ceiling — was the single largest line item on any of these six jobs. Finished cost: $31,200, the highest of the set, and almost entirely explained by that one plumbing scope.

What Six Projects Actually Cost, Side by Side

Across these six bathroom renovation projects, the average came out to just under $22,000, but the spread tells the real story: a $15,000 swing between the cheapest and most expensive job on rooms within five square feet of each other. The size of the room barely moved the price. What moved the price, every single time, was whether the stack, the joists, or the vent path cooperated. If you want the broader cost framework for a full house rather than one bathroom, our home remodeling cost guide for Delaware County breaks down per-square-foot tiers across every room type, and our piece on bathroom remodeling costs in West Chester rowhomes walks through a related but distinct housing stock just a few miles away.

Fixture Sizes That Actually Worked in a Room This Small

A few patterns held across all six jobs that are worth naming directly, because they're the specifics most "small bathroom ideas" roundups skip. A 30x60 or 32x60 shower is the realistic floor for a walk-in shower in a room under 40 square feet once you account for door swing and a usable vanity run — anything smaller forced a neo-angle or quadrant unit, which costs more per square foot of usable shower space. Wall-hung and pedestal sinks won in four of the six cases over a standard vanity cabinet, purely because they gave back 4 to 6 inches of floor clearance that mattered more than the storage a cabinet would've added. Round-bowl and comfort-height toilets with a short 24-inch footprint showed up in the two tightest rooms; a standard elongated bowl simply didn't leave enough clearance to the tub or shower door on either job.

Per the EPA's WaterSense fixture program, a WaterSense-labeled toilet uses 1.28 gallons per flush or less without sacrificing performance, and every fixture we specified on these six jobs carried that label — worth checking for on your own fixture list, since it's a line item some contractors skip without mentioning it.

Measure Your Own Bathroom: A One-Page Checklist

Before you call a contractor, walk your own bathroom with a tape measure and answer these five questions. It won't give you a final number, but it will tell you which of the six constraints above you're dealing with.

1. Measure wall to wall, twice. Note the shortest dimension — that's almost always what limits your shower or tub choice, not the overall square footage.
2. Find your joist direction. In an unfinished basement below, or through an outlet cover upstairs, check which way the joists run relative to where you want the drain to move.
3. Identify the stack. If you can see any exposed pipe in a basement or crawlspace near the bathroom, note whether it's cast iron (dull gray, heavy) or PVC (already replaced). That single fact predicts a meaningful swing in your renovation cost.
4. Check for an operable window or an existing fan. If neither exists, budget for a new mechanical vent run — and note whether there's attic access above the room, because that's the difference between an easy vertical duct and a longer horizontal one.
5. Look for "dead" space. A chimney chase that no longer vents anything, a shallow linen closet, or a furring wall hiding old pipe are the three most common sources of free square footage we find on site, and all three showed up in the six cases above.

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