From One-Piece Fiberglass to a Real Walk-In Shower: A Colorado Springs Conversion, Step by Step

A one-piece fiberglass tub-shower combo has a service life of roughly 10 to 15 years before the gelcoat dulls, the caulk lines stain, and hairline cracks start spidering across the floor pan. Plenty of Colorado Springs homes built in the 1990s and early 2000s are running on their original unit right now, well past that window. If that describes your hall bath or guest bath, a tub-to-shower conversion is one of the most satisfying upgrades you can make, and the fiberglass starting point actually makes the project cleaner than most people expect.

Here is why that matters: a molded fiberglass unit is a single shell, so the roofer, plumber, and tile setter are not fighting decades of mortar or a cast-iron tub weighing 300-plus pounds. That changes the sequence and, often, the timeline. Below is how a tub-to-shower conversion typically runs, stage by stage.

Stage 1: Confirm what you actually have

Before anyone quotes the work, the contractor needs to know whether your combo is a true one-piece unit or a multi-piece surround glued to a separate tub. One-piece shells usually cannot fit through a standard door or down a hallway intact, which means they get cut into sections during demo. Multi-piece units come apart more gently.

The crew also checks the wall behind the unit, the subfloor, and how the drain and supply lines are run. Say a homeowner in a two-story home off Austin Bluffs has a second-floor bath: the drain likely ties into a stack in the wall, which affects whether the shower base can sit where the tub sat or needs a small adjustment. This is the stage where surprises get found on paper instead of on demo day.

Stage 2: Decide the shower footprint and base

Most fiberglass combos occupy a 60-inch by 30-inch or 60-inch by 32-inch alcove. The good news is that the entire footprint becomes usable shower floor once the tub is gone, so a former 60x30 combo often becomes a genuinely roomy walk-in shower.

You will pick a base early, because everything downstream depends on it. A pre-formed acrylic or solid-surface base drops in fast and seals reliably. A tiled base built on a mortar bed and waterproof membrane gives you a custom look and lets you go low-threshold or curbless, but it adds days. If the bathroom is tight to begin with, our guest bath remodel framework for small Colorado Springs bathrooms is worth reading before you lock the layout.

Stage 3: Demo the old unit

With materials ordered, the crew protects floors and doorways, shuts off the water, and cuts the fiberglass shell into removable pieces. A one-piece unit that would never clear the door goes out in three or four sections. Because fiberglass is light, this part usually moves quickly, often inside a single morning for a standard combo.

Once the shell is out, the studs, subfloor, and rough plumbing are exposed. This is the moment the roofer and homeowner see whether there is hidden water damage behind the old caulk, a common find around the bottom track of an aging combo. If there is soft framing or a stained subfloor, it gets addressed now. Our post on deciding what survives a full bathroom remodel walks through how that keep-or-replace call gets made.

Stage 4: Adjust plumbing and framing

Fiberglass combos were built around a tub, so the drain sits in one corner and the valve is set at tub-filling height. Converting to a shower usually means relocating or reworking the drain to a shower base outlet and raising the valve to a comfortable standing height, typically around 42 to 48 inches. A realistic example: a homeowner keeping the shower in the exact tub footprint may need only a modest drain adjustment, while someone widening the opening or going curbless needs more framing and plumbing time.

The crew also frames any new features here, a bench, a recessed niche, a lower threshold, so the blocking is set inside the wall before waterproofing begins.

Stage 5: Waterproof, then build the walls

This is the stage that decides whether your shower still looks new in ten years. The base gets set and leak-tested, then the walls get their waterproofing layer, whether that is a membrane behind tile or the sealed seams of an acrylic or solid-surface system. Skipping or rushing this is the single most common reason a shower fails early, which is exactly the situation described in starting over when a previous remodel didn’t hold.

Wall panels or tile go up next, followed by the niche and bench finishes. Colorado Springs water runs hard, so many homeowners choose large-format panels or porcelain with minimal grout to cut down on mineral buildup and cleaning.

Stage 6: Fixtures, glass, and finish-out

With walls done, the crew sets the valve trim, shower head, handheld, and any body sprays, then installs the drain cover. Glass is measured and ordered based on the finished opening, so a frameless enclosure or a fixed panel may arrive a bit later than the rest of the work. The bathroom stays usable in the meantime as long as the water is on.

Final steps are sealing, caulking, a full clean, and a walk-through where the roofer runs the water and checks drainage and any pooling. Payment on a project like this is usually structured in stages, which is covered in our guide to how bathroom remodel payments work in Colorado Springs.

Frequently Asked Questions

Isn’t ripping out a fiberglass tub going to wreck my walls and floors?

Less than you would think. Because the shell is lightweight and cut into sections, demo is controlled rather than brute-force. The framing and subfloor stay in place unless there is existing water damage, in which case fixing it now is far cheaper than fixing a rotted floor later. A tidy demo is one of the reasons fiberglass conversions tend to run smoother than cast-iron tub removals.

Can the new shower go exactly where the tub was so I don’t pay to move plumbing?

Often, yes. If you keep the same footprint and drain location, the plumbing changes are usually modest, mostly raising the valve and reworking the drain to a shower outlet. Costs climb when you widen the opening, go curbless, or relocate the drain across the room. If you want to keep the number down, staying in the original alcove is the move.

We only have one full bathroom. Are we stuck without a shower for weeks?

Not for a standard fiberglass-to-shower conversion. The demanding stages, base-setting and waterproofing, need cure and dry time, but the total downtime is usually days rather than weeks, and the room is often usable again once the shower is watertight even if the glass arrives later. Ask the roofer to map the schedule around your household before work starts.

Thinking about trading a tired fiberglass combo for an open, easy-to-clean walk-in shower? You can get matched with an independent Colorado Springs bath specialist for a free in-home design consult, and see how the process would run in your own Colorado Springs bathroom.