Building a curbless shower in a 1950s Cape or a Victorian in Cambridge is a very different job than dropping one into new construction. The floor joists weren't sized for a recessed pan, the drain isn't where you need it, and the subfloor is often 3/4" pine board that flexes when you look at it. But a properly built ADA compliant shower in Massachusetts is one of the highest-value renovations you can do — for aging in place, for accessibility, and for a bathroom that simply feels better. Here's how we build them right, what it costs, and where the code actually applies.
Curbless vs. ADA-Compliant: They're Not the Same Thing
People use these terms interchangeably, but they mean different things, and the distinction affects your budget.
A curbless shower is a design choice — the shower floor is flush with the bathroom floor, no threshold to step over. Anyone can build one and it looks fantastic. But being curbless does not automatically make a shower ADA-compliant.
A true ADA-compliant shower meets specific dimensional and hardware requirements pulled from the ADA Standards for Accessible Design and the ICC A117.1 accessibility standard that Massachusetts references. That means:
- Roll-in showers must be at least 30" × 60" clear, with no curb higher than 1/2" (and that half-inch must be beveled).
- Grab bars rated to support 250 lbs, mounted 33"–36" above the floor.
- Controls and valve must be reachable from a seated position and located on the wall opposite the seat, or on the control wall in a roll-in unit.
- A folding seat mounted 17"–19" off the finished floor.
- A handheld shower on a slide bar with a hose at least 59" long.
Most of our residential clients in Winchester, Lexington, and Newton want a curbless shower that's ADA-adaptable — built to accessible dimensions with blocking in the walls so grab bars and a seat can be added later without opening up tile. That's the smart middle ground for aging in place. If you have a household member using a wheelchair now, we build to full roll-in spec.
The Real Challenge: Recessing the Pan in an Older Home
The hard part of a curbless shower isn't the tile — it's getting the water to drain when the floor is flat. To keep the shower flush with the bathroom, the shower pan needs to sit lower than the surrounding floor so you can pitch it 1/4" per foot to the drain. In new construction that's easy. In a 90-year-old home in Medford or Somerville, it means we're working with what the joists give us.
Option 1: Sistering and Recessing the Joists
When there's enough joist depth, we notch or fur down the framing to create a recessed area for the pan. This has to be done carefully — you cannot just cut into structural joists wherever you want. The Massachusetts State Building Code (780 CMR, based on the IRC) strictly limits notching to the outer third of a joist and no deeper than 1/6 of the joist depth. Cut it wrong and you've compromised the floor. We frequently sister new members alongside the originals to carry the load, then recess between them.
Option 2: Building the Floor Up
When we can't drop the pan — often on a concrete slab or when there's radiant heat below — we raise the rest of the bathroom floor instead, then transition with a low, gentle ramp. It's less elegant but it works, and it avoids touching the structure. On slab-on-grade homes in Waltham and Watertown, this is often the only realistic path unless you're willing to core the slab and re-route the drain, which adds real cost.
Linear Drains vs. Center Drains
The drain choice drives both the look and the difficulty of your bathroom remodel.
A center drain requires the floor to pitch from all four sides toward one point, which means four sloped planes and a lot of small-format tile or mosaic to follow the curve. It's the cheaper hardware but more labor-intensive tile work.
A linear drain sits along one wall (or across the entry in a roll-in design) and lets the entire shower floor pitch in a single direction. This is our default for curbless showers because:
- You can use large-format tile (even 24" × 24") on the floor since it only slopes one way.
- The single-plane slope makes a wheelchair-friendly, roll-in transition far easier.
- It looks clean and modern — the drain nearly disappears against the wall.
Linear drains cost more up front — a quality stainless unit runs $250–$600 versus $40–$80 for a standard center drain — but they save labor and are the right call for an accessible build. We set them in a bonded waterproofing system (Schluter-Kerdi or a liquid membrane), not the old rubber-liner-and-mud-bed method, because a curbless pan has zero curb to contain a leak.
Grab-Bar Blocking: Do It Now, Even If You Wait to Install
This is the single most important thing homeowners skip and later regret. Grab bars anchored into tile with plastic drywall anchors are dangerous — they'll pull out under load exactly when someone needs them. A real grab bar has to hit solid blocking behind the tile.
When the walls are open, we install continuous 2× blocking or 3/4" plywood backing across the entire wet wall and control wall at 32"–38" above the floor. That gives you the freedom to mount grab bars anywhere in that band later — no guessing where a stud lands, no cutting tile. It adds maybe $150–$300 in materials and an hour of labor during framing. Retrofitting it after the tile is up costs ten times that and leaves patch marks.
We build blocking into every accessible bathroom we do, even when the client only wants an ADA-adaptable design for now. It's cheap insurance for aging in place. You can see how we approach the full accessible layout on our ADA bathroom remodeling page.
What a Curbless ADA Shower Costs in Greater Boston
Pricing depends heavily on your existing conditions, but here are realistic ranges for the Greater Boston market as of this year. These reflect our work with no subcontractors — the crew that frames it also waterproofs and tiles it, which is why our waterproofing failures are essentially zero.
- Curbless shower conversion (standard tub-to-shower footprint): $9,000–$15,000
- Full ADA-compliant roll-in shower with linear drain, seat, and grab bars: $14,000–$22,000
- Complete accessible bathroom remodel (curbless shower, comfort-height toilet, ADA vanity, widened door): $28,000–$50,000+
The cost premium for going curbless versus a standard curbed shower is typically $2,500–$5,000, driven by the structural recessing, the linear drain, and the more demanding waterproofing. On a slab where we have to raise the floor or re-route drainage, add more.
A few things that move the number: whether the drain has to be relocated (a plumber-day of work plus opening the floor), whether we find rotted subfloor or knob-and-tube wiring when we open the walls (common in Arlington and Belmont's older housing stock), and your tile selection. Handmade zellige at $30/sq ft tiles very differently than a $4 porcelain plank.
Permits and Inspections in Massachusetts
A curbless shower remodel almost always requires a building permit from your local building department, and if you're moving the drain or valve, a separate plumbing permit as well. Under 780 CMR, any work that alters the structure — which recessing joists absolutely does — is not exempt from permitting. Some homeowners try to skip this; don't. An unpermitted bathroom is a problem at resale and voids most homeowner insurance claims if water damage occurs.
In towns like Stoneham, Woburn, and Burlington, the building inspector will typically want to see a rough inspection before we close the walls — that's when they verify the blocking, framing modifications, and waterproofing prep. The plumbing inspector checks the drain slope and venting. As a licensed general contractor, we pull the permits under our own license (CSL-121587), schedule the inspections, and handle the inspector walk-throughs so you're not managing any of it.
FAQ
Can any bathroom be converted to a curbless shower?
Almost any, but the difficulty varies enormously. A wood-framed bathroom over a basement or crawlspace is the easiest — we have access from below to recess the pan and move the drain. A bathroom on a concrete slab is the hardest and may require a raised floor with a gentle ramp instead of a fully recessed pan. We can tell you which situation you're in within about ten minutes of looking at your floor and what's below it.
Do I need to make my shower fully ADA-compliant, or can I build it "accessible-ready"?
For most homeowners planning to age in place, we recommend an ADA-adaptable build: accessible dimensions, a curbless entry, and full grab-bar blocking in the walls, but you install the bars and seat only when you need them. That gives you a clean, modern shower now and instant accessibility later without another renovation. Full ADA spec is required if you're using it for a wheelchair today or if it's a rental unit subject to accessibility rules.
How long does a curbless shower installation take?
A straightforward curbless conversion runs about 2–3 weeks. A full accessible bathroom remodel is typically 3–5 weeks depending on structural work, tile complexity, and inspection scheduling. Because we don't use subcontractors, we're not waiting on a plumber or tile crew to fit us into their calendar — our schedule is our schedule, which is a big part of why we hit our timelines.
Build It Once, Build It Right
A curbless, ADA-compliant shower is unforgiving of shortcuts — a bad slope pools water, missing blocking makes grab bars useless, and cheap waterproofing on a zero-curb pan leaks straight into the framing below. It's exactly the kind of project where doing it right the first time matters most.
Schlickmann Construction is a licensed Massachusetts general contractor (CSL-121587) with an A+ BBB rating and a 5.0★ Google review record, serving Stoneham, Lexington, Winchester, Medford, Woburn, Burlington, Waltham, Newton, Cambridge, Somerville, Arlington, and surrounding Greater Boston towns. We self-perform every part of the job — no subcontractors — so the crew that frames your shower is the same crew that waterproofs and tiles it. Contact us for a free estimate on your curbless or ADA-compliant shower, and we'll tell you honestly what your home can support and what it will cost.
