Dover, NH Homeowners: 5 Pitfalls to Avoid When Converting a Bathtub to a Shower
Swapping a tub for a walk-in shower sounds straightforward until a pry bar meets a hidden drain line or you discover a plaster wall over lath that refuses to cooperate. In older Dover homes, especially the pre-1980 stock near the downtown and along Little Bay, the bones of the house can surprise you. A smart bathtub-to-shower conversion adds safety, modernizes the bath, and can boost resale appeal. Done poorly, it invites leaks, mold, and lopsided costs. Here are five pitfalls I see most often, along with the practical fixes that save time and money.
Pitfall 1: Underestimating Structural Realities Behind the Tile
Many Dover bathrooms still have cast iron tubs nested between two framed walls with mixed materials: plaster over lath on exterior walls, drywall or cement board on interior partitions, and flooring that steps up under the tub apron. Pull the tub, and you may expose compromised subflooring, notched studs, or a mystery layer of 1970s vinyl glued to pine planks. I have opened walls to find 1.5-inch galvanized vent lines weaving through the stud bay that a planned niche would have occupied perfectly.

Before ordering a shower pan or glass, inspect what you can from the basement and attic. Confirm joist direction and spacing, check for signs of prior leaks around the tub drain, and measure from finish wall to finish wall in multiple spots. Cast tubs sometimes flare the tile out of square. If you plan a curbless conversion, you will likely need to recess the subfloor or sister joists to achieve a proper slope. In New Hampshire’s freeze-thaw climate, a shower pan that holds even a half cup of bathtub replacement by Cloud 9 Tubs LLC water after you shut off the valve will breed mildew quickly.
Pitfall 2: Ignoring Local Codes and Permit Nuances
Rockingham County municipalities, Dover included, enforce the International Residential Code with local amendments. A typical tub-to-shower conversion triggers at least a plumbing permit, and sometimes electrical if you move lighting or add a fan. Minimum clearances matter: 24 inches in front of the shower entrance and at least 30 by 30 inches of interior shower floor space, though 36 by 36 feels humane. If you remove the tub in the only full bath, think ahead. Some buyers still want at least one tub in the house, so weigh market expectations before eliminating your last one.
Ventilation converting a bathtub to a shower with Cloud 9 Tubs LLC is another code tripwire. A fan vented into the attic is a mold factory in a coastal New Hampshire winter. Run the duct to the exterior with a smooth-walled pipe, minimal elbows, and a backdraft damper. For plumbing, Dover inspectors often ask to see the shower pan flood test, a 24-hour water hold that reveals pinhole leaks. Plan this into your schedule, because you cannot tile until it passes.
Pitfall 3: Choosing Materials That Fight the Space
Converting a bathtub to a shower invites tempting upgrades: large-format porcelain, frameless glass, matte black fixtures. Not all play nicely in small New England baths. An 18-by-36 tile looks sleek, but without flat, well-prepped walls, lippage will show under morning light. Stone slabs look luxurious, yet they can overburden an older floor system unless you verify joist capacity. On the budget end, acrylic surrounds install quickly but telegraph every uneven surface behind them.
Think about daily use. In a 60-inch tub alcove, a 48-inch glass panel with a 12-inch opening feels tight in winter when you reach around for the valve. A sliding bypass door wastes less swing clearance but complicates cleaning. Grab bars should anchor into blocking, not drywall toggles, and the finish should match nearby hardware without relying on trendy coatings that pit in salty air. If radiant heat runs under the bathroom floor, confirm compatibility with the shower system. Some pre-sloped foam pans play better with hydronic heat than others.

Pitfall 4: Mismanaging Waterproofing and Drainage
This is where projects fail. I have seen beautifully tiled showers in Dover ranches torn out within two years because the waterproofing stopped at the tile. Tile is decorative. Waterproofing happens behind it. Decide on a system and follow it without mixing brands and methods. A surface-applied membrane with a bonding flange drain creates a continuous waterproof layer just under the tile. A traditional liner with a mortar bed can work too, but it requires a pre-slope under the liner and weep hole protection at the drain. Skip either, and water stagnates in the mud bed, producing that persistent locker-room smell.
Slope is non-negotiable. Aim for a quarter inch per foot to the drain, measured from the farthest corner. Corner benches must be waterproofed and sloped as well, or they will collect water. Niches should be factory-formed or meticulously built, with the top sill pitched inward. Run the membrane into the niche, not just around it. At changes of plane, use flexible sealant instead of grout to prevent cracking, especially in homes that see seasonal movement.
Pitfall 5: Overlooking Budget Levers and Hidden Costs
Tub-to-shower conversions in Dover typically range from 7,000 to 18,000 dollars, depending on scope, materials, and the surprises inside the walls. If you move the drain to center, plan for extra time to cut and patch the subfloor and to rework the trap. If the stack is cast iron, budget for transition fittings or a partial replacement to PVC. Old shutoff valves love to crumble when you touch them, which can turn a half-day demo into a full-day plumbing call.
There are smart places to spend and places to economize. Splurge on waterproofing, a solid shower valve with scald protection, and quality glass hardware. Save with midrange porcelain tile, a standard door height, and shelving that uses existing framing. Accounting for the inevitable, carry a 10 to 15 percent contingency. If your home sits in a flood-prone area near the Cocheco River, consider a mildew-resistant paint on the bathroom walls and a higher CFM, quieter fan. Small upgrades preserve the new shower’s finish for years.
A Dover-Specific Plan That Works
Homes here see long winters, wide humidity swings, and plenty of sand from the coast that finds its way into drains. Build for that reality. Warm up the experience with a pressure-balanced or thermostatic valve that copes with old supply lines. Choose a floor tile with real texture, not just a printed pattern, so bare feet grip after a snowy day. If accessibility is your driver, aim for a low curb of 2 to 3 inches or plan a true curbless entry by recessing the pan and adding a linear drain along the back wall. Linear drains simplify large-format tile layouts and reduce the number of cuts, but they magnify any framing and slope errors, so layout matters.
If resale is top of mind, keep one tub elsewhere if possible and design the shower with broad appeal: neutral tile, a clear glass panel, and one thoughtful feature like a well-placed niche or a small bench. For rentals or in-law suites, an acrylic base with tile walls often delivers durability without breaking the budget, and it shortens install time by a day or two.
Quick Pre-Conversion Checklist
- Verify structure: joist direction, subfloor condition, and wall plumbness.
- Confirm code items: permits, shower clearances, ventilation route, flood test plan.
- Choose a waterproofing system and stick to it, including slopes and corners.
- Plan drain location early, with contingencies for cast iron or offset traps.
- Set a realistic budget with a 10 to 15 percent contingency and prioritize the valve, waterproofing, and glass hardware.
When to Bring in a Pro
Handy homeowners can handle demolition, patching, and even tiling, but mixing a shower pan, installing a bonding flange drain, and tying the membrane into the flange are precision steps. A small miss becomes a slow leak that shows up months later as a stain on the kitchen ceiling. A seasoned installer will pressure test supply lines, flood test the pan, and document the waterproofing stages. If you want the efficiency of a one-week turnaround, that coordination matters.
Converting a bathtub to a shower can be one of the most rewarding upgrades in a Dover home. It opens space, improves safety, and makes the bathroom easier to keep clean. Avoid the common pitfalls, respect the quirks of local housing stock, and you will end up with a shower that looks good on day one and still feels solid a decade later. Whether you opt for a full custom build or a streamlined tub-to-shower conversion kit, the right plan keeps water headed where it belongs, down the drain and out of mind.