Southern NH & Northern MA Bathroom Remodeling Guide
What This Guide Covers
- The right way to waterproof showers, tubs, and floors
- How to size and route a bath fan so moisture leaves the house
- Simple layout rules that make small baths feel bigger
- Typical budgets and timelines for New England homes
- What inspectors look for in Southern NH and Northern MA
Start Here: A Clean, Dry Shell
Before tile or fixtures, confirm the "shell" is sound.
Fix Leaks First
Address any old supply or drain leaks, stained subfloor, soft drywall, or window flashing issues.
Check Structure
Subfloor must be solid and flat. Sister joists or add underlayment if needed.
Plan Penetrations
Keep wall openings tight and sealed around valves, niches, and fan ducts.
Waterproofing That Actually Works
Showers
Use a bonded waterproofing system
Examples include liquid membranes or sheet membranes installed over cement board. Tile and grout are not waterproof.
Continuous coverage
Membrane should run up walls, across the pan, and over curb with sealed seams.
Proper slope
Minimum 1/4" per foot toward the drain. No flat spots.
Drains that match the system
Pair the correct bonding flange or clamping drain with your membrane.
Niches and benches
Preformed waterproof units are safest. If site-built, wrap every surface and corner with membrane and factory corners.
Tubs and Splash Zones
Tub surrounds
Waterproof to at least the height of the showerhead.
Valve wall
Seal around mixing valves and spouts with gaskets or membrane patches.
Floor edges
Run waterproofing a few inches out from the tub or curb to catch splash.
Bathroom Floors
Crack isolation + waterproofing
In small baths, a roll-on membrane under tile helps with minor movement and protects from spills.
Toilets and vanities
Seal the flange to the finished floor height. Caulk vanity bases to keep mop water out.
Venting: Get Steam Outside, Quietly
Fan Sizing
Rule of thumb
1 CFM per square foot for an 8' ceiling (minimum 50 CFM).
Upgrade for larger rooms or enclosed toilets
80–110 CFM is common for a primary bath.
Long ducts or many elbows?
Up-size CFM or use a fan designed for higher static pressure.
Duct Routing
Shortest, straightest run to the exterior
Roof or sidewall cap with backdraft damper.
Use smooth metal duct where possible
Seal joints with foil tape, not cloth duct tape.
Insulate ducts in unconditioned spaces
To prevent condensation.
Switch control
Add a timer or humidity-sensing switch so the fan runs 20–30 minutes after showers.
Smart Layouts That Live Better
Simple Rules
The 3 clear zones
Shower/tub, toilet, and vanity. Keep at least 30" clear width in front of each.
Doors that do not collide
Pocket or outswing shower doors save space.
Vanity first, then toilet
Place the vanity nearest the entry for daily convenience.
Glass where possible
Frameless glass opens sight lines and makes small rooms feel bigger.
Small Bath Playbook (5' × 8')
Layout A
60" tub or shower at one end, toilet centered, 24–30" vanity opposite the door.
Layout B (shower only)
48–60" shower with linear drain, wall-hung toilet, 30" floating vanity to show more floor.
Accessibility and Aging-Friendly Touches
- Curbless showers with linear drains
- Blocking in walls for future grab bars
- Wider door (32–36") and lever handles
- Wall-hung vanities for knee clearance
Materials That Last
Backer Board
Cement board or fiber-cement in wet zones. No paper-faced drywall in showers.
Tile
Porcelain for floors and showers. Smaller tile or mosaics on pans for better grip and slope.
Grout
High-performance cement grout or epoxy grout for stain resistance.
Glass
Tempered, properly sized with channels or clips sealed to curb and walls.
Sealants
100% silicone at all changes of plane (wall-to-floor, wall-to-wall, glass-to-tile).
Inspections and Local Code Notes
- GFCI protection for receptacles
- Dedicated circuits for heat floors, whirlpool pumps, or high-draw hair tools
- Fan vented outdoors, not to an attic
- Safety glazing near wet zones
- Egress and smoke/CO rules apply to the home as a whole; updates can trigger smoke/CO upgrades in some towns
What It Costs (Typical Ranges)
Prices vary by size, selections, and hidden repairs. These ballparks help with planning.
Pull-and-Replace Hall Bath (5' × 8')
$22k–$35k
Primary Bath with Tiled Shower
$35k–$60k
Curbless Shower + Heated Floor + Custom Glass
$55k–$85k+
Premium Stone, Custom Vanity, High-End Fixtures
$80k–$120k+
Includes design, permits, demo, rough trades, waterproofing, tile, vanity, tops, plumbing trim, lighting, paint, and glass. Structural repairs or layout changes add cost.
How Long It Takes
Design and selections
2–4 weeks
Lead times (vanity, tops, glass)
2–6 weeks in parallel
On-site build
Hall bath: 3–5 weeks
Primary bath with custom tile/glass: 5–8 weeks
Note: Glass often comes last. Measure after tile, fabricate, then install a week or two later.
Our Proven Build Order (No Rework, No Surprises)
- Protect floors and set dust control
- Demo and disposal
- Rough plumbing, electrical, and framing changes
- Inspections
- Backer board, heat mat (if used), and full waterproofing
- Tile install and grout
- Paint and trim
- Fixtures, lighting, and accessories
- Shower glass measure → fabricate → install
- Final clean and walkthrough
Maintenance That Keeps It Fresh
- Run the fan during showers and 20 minutes after
- Squeegee glass and tile once a day
- Reseal grout if using cement-based grout (as directed)
- Check caulk at changes of plane yearly and refresh when needed
Ready to Plan Your Bathroom?
We'll help you pick a layout, get the waterproofing right, and keep the schedule tight. Share a few photos and rough measurements, and we can start a realistic plan and budget.
Service area: Derry, Londonderry, Salem, Windham, Bedford, Manchester, Pelham, Hampstead, Kingston, Danville, Chester NH • Groton, Dunstable, Littleton, Westford, Concord, Carlisle, Pepperell, Ayer MA
Frequently Asked Questions
What is the best waterproofing for a shower?
A bonded sheet or liquid membrane over cement board, tied into a compatible drain, gives reliable protection when installed to the manufacturer's specs.
Can I put a curbless shower in a second-floor bath?
Often yes. It may require lowering the subfloor between joists, a linear drain, and careful planning, but it is common in remodels.
Do I need a 2" drain for the shower?
Most tiled showers use a 2" trap and drain. Some codes allow 1-1/2" only for small flows, but 2" is the safe standard.
How big should my bath fan be?
Aim for at least the room's square footage in CFM for 8' ceilings, then add capacity for long or complex duct runs.
What tile is best for shower floors?
Matte porcelain mosaics with lots of grout joints provide grip and bend to the slope. Large tiles fight the slope and can be slippery.