How to Convert an Old Bathtub into a Modern Spa in Just 3 Weeks

That oversized garden tub sitting unused in your master bathroom? It is taking up 15-20 square feet of prime bathroom real estate and contributing nothing to your daily life. In just three weeks, that dated tub can become a spa-quality walk-in shower with rain heads, body jets, heated floors, and every luxury feature you have envied in boutique hotel bathrooms. Here is exactly how it happens, week by week.

We have refined this process over hundreds of tub-to-shower conversions across Sacramento and Placer County. The 3-week timeline is not a marketing gimmick — it is the result of a specialized team, optimized sequencing, and deep experience with the specific challenges of converting tub spaces into premium shower environments.

The 3-Week Transformation: What Makes It Possible

Many general contractors quote 4-8 weeks for a tub-to-shower conversion. The reason we can deliver in 3 weeks is not because we cut corners — it is because we do nothing but bathrooms. Our team knows exactly what needs to happen each day, materials arrive pre-scheduled, and our subcontractors are dedicated bathroom professionals who prioritize our projects.

The key to the 3-week timeline is pre-construction planning. Before any demolition begins, we have already completed the design, ordered all materials, scheduled all trades, and resolved any potential issues. When Day 1 arrives, every person on the team knows exactly what they are doing and in what order.

Here is the detailed breakdown of what happens each week.

Week 1: Demolition, Plumbing, and Structural Work (Days 1-5)

Day 1-2: Protection and Demolition

The project starts with protecting your home. We lay protective floor coverings from the front door to the bathroom, seal off adjacent rooms with plastic barriers, and set up HEPA-filtered dust management. Then the demolition begins.

The old bathtub, surrounding tile, drywall, and any deteriorated framing are removed. This is where we frequently discover issues that general contractors miss: hidden water damage from decades of minor leaks, deteriorated subfloor beneath the tub, inadequate framing, and outdated plumbing that needs updating. Our experience means we anticipate these discoveries and have solutions ready.

Day 3-4: Plumbing Rough-In

With the tub removed and the wall cavity exposed, our plumbers install new supply lines and drain configuration for the spa shower. This is the most critical phase for determining what spa features are possible in your space.

Supply plumbing is reconfigured from the single tub faucet supply to accommodate multiple shower outlets. A spa-level shower typically requires supply lines for a ceiling-mounted rain head, wall-mounted handheld wand, 4-6 body jets, and potentially a steam generator. All new supply lines use PEX tubing with proper shut-off valves.

Drain configuration is modified from the tub drain position to the shower drain location. Depending on your spa design, this may be a center point drain or a linear drain (preferred for curbless entry). The drain must connect to the existing drain line while maintaining proper slope for reliable drainage.

Electrical rough-in happens simultaneously. Dedicated circuits are run for heated floor mats, steam generators, LED lighting, and digital controls. Each of these features requires its own circuit to meet code requirements.

Day 5: Structural Completion and Inspection

Any structural repairs or modifications are completed: reinforced blocking for grab bars, bench support framing, header support if wall modifications were needed, and replacement of any damaged subfloor. The shower floor is prepared with either a mortar bed (for center drains) or a pre-sloped foam pan (for linear drains).

A rough-in inspection is scheduled with the local building department (for projects requiring permits). This inspection verifies plumbing, electrical, and structural work meets code before we close the walls.

Week 1 in action — the old tub is gone, new plumbing is roughed in, and the shower space is taking shape. This is where the spa transformation begins.

Week 2: Waterproofing, Tile, and Surface Installation (Days 6-10)

Day 6-7: Cement Board and Waterproofing

Cement backer board is installed on all shower walls and the shower bench. This provides the rigid, moisture-resistant substrate that tile requires. Unlike drywall, cement board will not deteriorate from moisture exposure.

The complete waterproofing system is installed over the cement board. We use bonded waterproofing membranes (Schluter KERDI or equivalent) that create a continuous, crack-resistant moisture barrier. Every seam, corner, pipe penetration, and transition point is sealed with waterproofing band and membrane. The shower floor receives a complete waterproofing layer that connects seamlessly with the wall membrane.

This is arguably the most important day of the entire project. Proper waterproofing is what separates a shower that lasts 30 years from one that fails in 5. Our team's daily experience with shower waterproofing means every detail is executed with precision.

Day 7-10: Tile Installation

Tile installation is where your spa vision becomes reality. Our tile installers begin with the shower floor (small format mosaic or large format with linear drain), then move to the walls, bench surfaces, and niche interiors. Each surface is laid with attention to layout symmetry, pattern alignment, and grout joint consistency.

For spa-quality conversions, we typically recommend:

• Walls: Large format porcelain (12x24 or larger) in marble or stone look for a clean, luxurious backdrop
• Floor: Textured mosaic for slip resistance and proper drain slope conformity
• Bench: Matching wall tile or complementary accent tile for a built-in, integrated look
• Niches: Glass mosaic or accent tile to create jewelry-box focal points
• Accent features: Decorative border band, feature wall, or herringbone panel for design interest

The heated floor mat is embedded in the mortar beneath the tile, connected to its dedicated thermostat. Once tiled over, the heating element is invisible — you only know it is there when you step onto warm tile on a cold morning.

Week 3: Glass, Fixtures, and Finishing Touches (Days 11-15)

Day 11-12: Grout and Curing

All tile joints are grouted — epoxy grout for the shower interior (waterproof and stain-proof) and modified cement grout for areas outside the shower. Grout requires 24-48 hours of curing before the shower can be used, so we use this time productively.

Day 12-13: Glass Enclosure Installation

The frameless glass enclosure is installed. Because we measure for glass during Week 1 and submit to our fabricator immediately, the custom glass panels arrive during Week 2 and are ready for installation as soon as the grout has cured. This precise scheduling eliminates the 2-3 week delay that many contractors experience waiting for glass.

Day 13-14: Fixture Installation

All spa fixtures are installed and connected: the rain shower head, handheld wand, body jets, thermostatic valve with digital controls, steam generator head, LED recessed lighting, and any other features. Each fixture is tested for proper function, water pressure, and temperature accuracy.

Day 15: Final Details and Walkthrough

The finishing touches make everything perfect: silicone caulking at all transitions, mirror and accessory installation, paint touch-ups, exhaust fan installation, and a thorough cleaning. We conduct a detailed walkthrough with you, demonstrating every feature, explaining care and maintenance, and addressing any questions.

Your spa shower is ready to use. Three weeks from demolition to first shower.

Spa Features That Transform Your Daily Routine

The beauty of a bathtub-to-spa conversion is the opportunity to incorporate features that turn your daily shower into a wellness experience. Here are the most popular spa features our Sacramento-area clients choose:

Must-Have Spa Features

• Ceiling rain shower head (10-12 inch): The foundation of any spa shower. Delivers a gentle, full-body cascade from directly above. ($300-$1,500)
• Handheld wand on slide bar: Practical for everyday use and essential for rinsing. ($100-$500)
• Built-in tiled bench: Provides seating for relaxation, shaving, and accessibility. ($800-$2,000)
• Frameless glass enclosure: Showcases your spa and makes the bathroom feel spacious. ($1,500-$3,500)
• Lighted shower niche: LED-lit storage niches add ambiance and function. ($300-$800)

Premium Spa Upgrades

• Body jet system (4-8 jets): Targeted hydrotherapy massage for shoulders, back, and legs. ($1,500-$4,000)
• Steam generator: Transforms your shower into a personal steam room. ($4,000-$10,000)
• Digital controls: Precise temperature, user presets, smartphone integration. ($1,500-$4,000)
• Radiant heated floor: Warm tile underfoot in the shower and beyond. ($1,300-$3,500)
• Chromatherapy lighting: Color-changing LED system for mood enhancement. ($500-$1,500)
• Built-in Bluetooth speakers: Waterproof speakers for music or podcasts. ($300-$800)

The finished product: a spa-quality walk-in shower with rain head, body jets, tiled bench, and ambient lighting — where that old bathtub used to be.

Cost Tiers: Good, Better, Best

Understanding the investment at different quality levels helps you plan a conversion that matches both your spa dreams and your budget.

Good: Premium Shower ($10,000-$15,000)

Removes the tub and creates a beautiful walk-in shower with quality porcelain tile, rain head, handheld, frameless glass, and a built-in niche. This is not a basic shower — it is a significant upgrade that feels luxurious daily. Perfect for secondary bathrooms or budget-conscious master bath upgrades.

Better: Spa Shower ($15,000-$20,000)

Everything in the Premium tier plus body jets (4-6), built-in bench, heated shower floor, multiple niches with accent tile, linear drain with curbless entry, and digital temperature controls. This tier delivers the true spa experience that most homeowners envision.

Best: Ultimate Spa ($20,000-$30,000+)

Everything in the Spa tier plus steam generator, chromatherapy lighting, Bluetooth speakers, premium natural stone or large-format porcelain slab tile, extended heated floors throughout the bathroom, and top-tier digital controls with smartphone integration. This is the complete home spa that rivals boutique hotels.

How to Prepare for Your 3-Week Conversion

Proper preparation ensures the project runs smoothly and minimizes disruption to your household.

Before the Project Starts

• Clear the bathroom completely: Remove all personal items, toiletries, towels, and decorations. Everything in the bathroom needs to be relocated.
• Arrange alternative bathroom access: If this is your only bathroom, plan for alternative shower and toilet access during the project. Many clients use a gym membership or make arrangements with nearby family or friends.
• Clear a path from the front door: We need a clear path for material deliveries and debris removal. Move furniture or obstacles that might be in the way.
• Plan for noise and dust: Demolition days are the loudest. If you work from home, plan accordingly. We use dust barriers, but some dust migration is unavoidable.
• Protect nearby areas: We protect your floors and walls along the work path, but moving fragile items or valuable rugs from the hallway near the bathroom is a smart precaution.

During the Project

We keep you informed daily with progress updates and photos. Our project manager is your single point of contact for questions or concerns. We clean up at the end of each work day and respect your home as if it were our own.

At OakWood Remodel, the bathtub-to-spa conversion is one of our signature projects. Our team (CSLB #1125321) has the specialized experience, supplier relationships, and refined process to deliver your dream spa shower in just three weeks. Whether you are in Rocklin, Roseville, Auburn, Granite Bay, or anywhere in the Sacramento region, we bring the same level of expertise and attention to detail to every project.

Ready to trade your unused tub for a daily spa experience? Contact us for a free consultation, or call (916) 907-8782 to start planning your transformation.