Dover, NH Guide: 5 Mistakes People Make When Converting a Bathtub to a Shower
Replacing a tub with a walk-in shower can transform a Dover home. It can make a tight bathroom feel larger, improve accessibility as stairs and knees get less friendly, and boost daily comfort in a climate where hot showers matter half the year. Yet a straightforward bathtub-to-shower conversion hides traps behind the tile. I have seen projects go sideways for reasons that seem small at the outset but cost weeks and thousands later. If you are considering converting a bathtub to a shower, especially in older Seacoast homes with mixed plumbing vintages, a little planning pays off.


Mistake 1: Ignoring the drain location and slope
Tubs often drain at the end. Many shower pans center the drain. That mismatch sounds minor, but it drives labor. Moving a drain even 8 to 12 inches can require opening the subfloor, rerouting 2-inch ABS or PVC, and adjusting the trap to maintain a proper slope of roughly 1/4 inch per foot. Salisbury Street capes built in the 1950s might still carry 1.5-inch tub drains, which are undersized for showers under current code. If you skip the upgrade, you invite slow drainage and standing water.
A Dover job last winter looked simple at first glance. Once we opened the floor, we found a shallower joist bay above a stubborn beam. The drain could not move to center without notching structure, which is off limits. The fix was a custom receptor with an end drain and a slight shift in valve placement to keep it visually balanced. The client saved both time and approximately 900 dollars in carpentry by adapting the plan instead of forcing it.
Mistake 2: Underestimating waterproofing in a coastal climate
Bathrooms in New England swing from steamy to chilly. Expansion and contraction pull at seams. Tile and grout are not waterproof by themselves, and cement board only resists moisture, it does not stop it. Skipping a continuous waterproofing membrane, either sheet or liquid-applied, invites mold behind the walls and swollen backer. I have pulled out showers that bathtub replacement installation tips looked fine at year one and failed at year four because a small gap at a niche let water track into the stud bay.
Pay attention to three spots: the wall-to-pan transition, inside corners, and niches or benches. Seal the flange correctly, run the membrane over it, and use pre-formed corners if you are using sheet material. For second-floor baths along Central Avenue, I prefer a bonded waterproofing system from studs to tile with flood testing before tile goes on. That 24-hour pause costs you a day, but it catches pinholes while repair is easy.
Mistake 3: Choosing surfaces for looks over maintenance
A tub-to-shower conversion often doubles as a design refresh, but Dover’s water can be moderately hard, and soap scum shows up fast. High-contrast grout, micro-textured stone, and heavy veining look striking on day one and fussy by month two if you do not seal and clean regularly. Oversized porcelain tile with a matte finish keeps traction without showing every droplet. If you love marble, consider a porcelain look-alike on the walls and reserve real stone for a small accent where you can maintain it easily.
Frameless glass is popular, but it puts water spots on full display. Ask for low-iron glass with a factory-applied protective coating, and plan for an angled drip rail so water does not creep onto the bath floor. If minimizing maintenance is the main goal, a high-quality solid-surface wall system can be a smart choice. Good brands mimic tile lines without grout, and they install in a day after prep.
Mistake 4: Overlooking structure and permitting
Dover is renovation-friendly, yet the city still expects plumbing permits when converting a bathtub to a shower, and electrical permits if you move lights or add a fan. Skipping permits can complicate a future sale and leave you uncovered if a leak damages a downstairs ceiling. I have had closings delayed because a buyer’s inspector spotted an unpermitted tub-to-shower conversion and the lender asked for retroactive approvals.
Structural surprises are equally common. A cast iron tub weighs 300 to 400 pounds and spreads load along the floor. Replacing it with a curbless shower concentrates load at the pan and requires subfloor modification. Before you dream about a zero-threshold entry, check joist direction, spacing, and span. Many 1920s homes near the Cocheco River use true 2x8s with long runs. You might need to sister joists or choose a low-profile curb instead. The smart sequence is inspection, permit, then demolition. Not the other way around.
Mistake 5: Designing without the people who will use it
The best tub-to-shower conversions reflect how the family moves and ages. A six-foot person wrestling with a 72-inch hose will constantly knock the handheld into the wall. A 5-foot user may have the showerhead spraying above their usable zone if the arm is set too high. If a parent will move in within five years, build the blocking now for future grab bars. Blocking adds minutes when walls are open and saves a full day later.
Think through everyday moves. Where does shampoo live? A niche that looks symmetrical often ends up too high to reach with eyes closed. Place at shoulder height for the shortest user. Benches should be about 17 to 19 inches high and 15 inches deep. If space is tight in a 60-inch alcove, a fold-down teak seat keeps elbow room. For water temperature, thermostatic valves cut surprises when the dishwasher kicks on, and pressure-balance is acceptable but less precise. Dover winters make warm-up time relevant, so a diverter that sends water to the handheld first helps you avoid the cold blast.
Local considerations that shape the project
Older Dover homes mix copper, galvanized, and PEX. When planning a tub-to-shower conversion, assume you will replace at least the supply lines within the wall cavity. If a pressure-reducing valve near the main has drifted, showers sputter when other fixtures run. It is a quick test with a gauge and a modest fix that avoids callbacks.
Ventilation matters more than most clients expect. A new, tighter shower adds moisture to the room. Choose a fan rated for at least 80 to 110 CFM in smaller baths, and verify ducting routes outdoors, not into the attic. I see a lot of 50 CFM fans on Lafayette Road that never kept up.
Winter installation can be smoother than summer if you plan for temperature control during tile curing. Keep the room above 50 degrees, protect pipes in exterior walls, and warm the thinset and grout. Rushing that step shows up later as hairline grout cracks.
Budget ranges that match typical Dover projects
Material choices swing costs far more than labor on a straightforward alcove. A prefabricated acrylic or composite pan with solid-surface walls, new valve, and glass can land in the 9,000 to 14,000 dollar range for most homes, permits included. Tile showers with upgraded plumbing and custom glass often land between 14,000 and 22,000 dollars, with stone benches, linear drains, or niches nudging the top end. If you need structural work, asbestos tile abatement under the old tub, or a full rewire with GFCI breakers, set aside a contingency of 10 to 20 percent.
A simple planning checklist
- Confirm drain size and location, and decide whether to move it or choose a matching pan.
- Select a waterproofing system and schedule a 24-hour flood test before tile.
- Align surfaces with maintenance reality, not just showroom appeal.
- Pull the right permits and verify fan ducting and electrical upgrades.
- Add blocking for grab bars, decide bench and niche heights, and test valve placement.
When a pro makes sense, and when DIY flies
If the plan keeps the drain put, uses a quality receptor, and you are comfortable with plumbing and finish work, an experienced DIYer can complete a conversion over two or three weekends. The line you should not cross lightly is waterproofing and glass. Tile tolerates very little error at the pan edge, and custom glass hinges need plumb walls within a few millimeters. Hiring a local installer for those critical steps, while you handle demo and painting, often balances budget and outcome.
Dover homes reward careful choices. Take time to map the drain, commit to robust waterproofing, pick materials you will enjoy cleaning, respect permits and structure, and design for real people. The result is a shower that works year after year, not just the week the caulk dries. If you want a second set of eyes, bring in a contractor early, even for an hour of consultation. That hour costs less than a miscut pan, and it sets the tone for a conversion that feels intentional rather than improvised.