Fiberglass vs. Acrylic vs. Onyx: Which Bathtub is Right for Your North Dakota Home?
Choosing a new bathtub or shower surround is a 20-year decision. In North Dakota, that decision is complicated by two things: extreme temperature shifts that cause houses to settle and notoriously hard water that eats through cheap materials.
If you’ve spent any time researching, you’ve likely run into the “Fiberglass vs. Acrylic” debate. While both are common, they aren’t created equal—and for many homeowners, neither is actually the best long-term choice. In this guide, we’ll break down the costs, durability, and maintenance of every major material so you can stop scrubbing and start relaxing.
1. Fiberglass: The Budget-Friendly (But Risky) Entry
Fiberglass, or Fiber-Reinforced Plastic (FRP), is the most affordable material on the market. It’s made by spraying a polyester resin over a mold and reinforcing it with glass fibers.
The Reality of Fiberglass:
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The Pro: It is incredibly lightweight and inexpensive. If you are flipping a house or on a razor-thin budget, fiberglass gets the job done quickly.
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The Con: It is thin and porous. Because the material is flexible, it “breathes” as you step into it. Over time, this flexing leads to “spiderweb” cracks in the finish.
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The ND Factor: Fiberglass is notorious for fading and staining. In regions with high mineral content in the water, those minerals get trapped in the porous surface, making it nearly impossible to get that “bright white” look back once it’s gone.
2. Acrylic: The Modern Standard
Acrylic tubs are made by heating a solid sheet of petrochemical composition and vacuum-forming it into a mold. It is then reinforced with fiberglass for stability.
Why Most People Choose Acrylic:
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Heat Retention: Unlike cast iron or thin fiberglass, acrylic is warm to the touch and keeps your bath water hot for longer.
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Non-Porous Surface: The finish is smoother than fiberglass, meaning soap scum and hard water have a harder time sticking to the walls.
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Durability: It is much thicker than standard fiberglass and won’t crack as easily under the weight of daily use.
The Downside:
While better than fiberglass, acrylic can still scratch if you use abrasive cleaners. It also has a “plastic” feel that some homeowners find less premium than stone or tile.
3. The Ultimate Comparison: Materials at a Glance
| Feature | Fiberglass | Acrylic | Tile & Grout | Onyx Solid Surface |
| Average Cost | $ | $$ | $$$ | $$$ |
| Ease of Cleaning | Difficult (Porous) | Moderate | Very Hard (Grout) | Easiest (Seamless) |
| Durability | Low (Cracks/Fades) | Moderate | High (Tiles)/Low (Grout) | Exceptional |
| Lifespan | 10–15 Years | 15–20 Years | 20+ Years | Lifetime Guarantee |
| Installation Time | 1–2 Days | 1–2 Days | 5–7 Days | 1–2 Days |
| Customization | Very Limited | Limited | High | Infinite Colors/Sizes |
4. The Problem with Tile and Grout
Many homeowners think tile is the “gold standard.” While it looks beautiful on Day 1, North Dakota’s climate creates a unique problem. Our ground shifts significantly between the deep freeze of winter and the humidity of summer.
When your house shifts, your grout lines crack. Once grout cracks, water gets behind the wall. This leads to mold, mildew, and eventually, structural rot. If you aren’t prepared to reseal your grout every year, tile might be more work than it’s worth. If you currently have failing tile, you may want to explore our shower replacement options to see how seamless walls can solve this problem permanently.
5. Why We Recommend Onyx for North Dakota Homes
After years of installing various materials, we have pivoted our recommendation to Onyx Solid Surface. Produced right here in the Midwest, Onyx is a hybrid of alumina trihydrate and high-performance resins.
It is “Midwest Tough”
Onyx is a solid-surface material. It doesn’t “flex” like fiberglass, and it doesn’t have a thin veneer like acrylic. It is solid all the way through. It handles the expansion and contraction of ND homes without breaking a sweat. You can see examples of these durable installs in our bathroom remodeling gallery.
Guaranteed Forever
Fiberglass and acrylic warranties usually cap out at 5 or 10 years (and often don’t cover “wear and tear”). Onyx comes with a “Yes, Guaranteed Forever” warranty. If it ever fails, it gets replaced. Period.
No Grout, No Stress
Onyx panels are custom-fit to your bathroom. This means you get the look of a premium stone or tile shower without a single grout line. For homeowners dealing with hard water, this is a game-changer—you simply wipe it down and you’re done.
Custom Fit for Any Space
Old ND farmhouses often have strange bathroom dimensions that “standard” big-box fiberglass tubs won’t fit. Onyx is custom-manufactured to your exact specifications, ensuring a watertight fit in any alcove. This flexibility makes it the top choice for our tub-to-shower conversions.
6. How North Dakota Hard Water Destroys Cheap Tubs
If you live in Fargo, Bismarck, or the surrounding rural areas, you know our water is “heavy.” High concentrations of calcium and magnesium are common.
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The Fiberglass Trap: Hard water minerals etch into the porous gel coat of fiberglass. Once that surface is etched, it acts like sandpaper, grabbing onto soap scum and skin oils.
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The Acrylic Edge: Acrylic is non-porous, meaning the water beads off more effectively. However, if you use the wrong cleaner to get rid of lime buildup, you can strip the shine off the acrylic permanently.
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The Onyx Advantage: Because Onyx is a solid-surface stone hybrid, it is chemically resistant. You can use vinegar-based cleaners to melt away hard water spots without worrying about damaging the integrity of the walls.
7. Maintenance: How to Protect Your Investment
Regardless of which material you choose, follow these rules to ensure it lasts:
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Avoid Abrasives: Never use steel wool or “gritty” cleaners (like Comet or Ajax) on acrylic or fiberglass.
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Squeegee is King: Taking 30 seconds to squeegee the walls after a shower prevents mineral buildup and keeps the “new” look longer.
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The Cleaning Secret: For Onyx and Acrylic, a simple mixture of 50/50 white vinegar and water is often the most effective way to kill hard water spots without damaging the finish.
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Check the Caulk: Even a lifetime material like Onyx requires fresh silicone caulk every few years at the joints to remain 100% waterproof.
8. The Cost-Value Gap: A Long-Term View
A fiberglass insert might cost $800 at a hardware store, while an Onyx system is a larger upfront investment. However, when you factor in the cost of professional installation, the price of specialized cleaners, and the fact that you will likely have to replace fiberglass twice in the time you’d own one Onyx shower, the “cheaper” option becomes the most expensive over time.
Investing in a high-quality solid surface doesn’t just make your life easier—it increases the resale value of your home. Buyers in North Dakota recognize the quality of a stone-hybrid finish over a plastic insert. Whether you are planning a full master bathroom remodel or a quick guest bath update, material quality is the most important factor.
Frequently Asked Questions (FAQ)
Q: Can I install Onyx over my old tile?
A: No. To ensure a lifetime seal, we always recommend a full “tear-out” to the studs. This allows us to inspect for water damage or mold before the new system goes in.
Q: Does acrylic or fiberglass turn yellow over time?
A: Lower-quality materials can yellow due to UV exposure or chemical reactions with harsh cleaners. High-quality, UV-stable Onyx and premium Acrylic are designed to hold their color for decades.
Q: How long does a full bathroom conversion take?
A: A typical fiberglass or acrylic insert takes 1–2 days. An Onyx system is similarly fast because it uses large, custom-fit panels rather than individual tiles. Learn more about our one-day remodel process here.
Q: Is Onyx slippery?
A: Onyx shower bases come with a molded-in non-slip texture that meets or exceeds ADA standards, making it much safer than a standard smooth fiberglass tub.
Ready to Upgrade Your Bathroom?
Don’t settle for a bathtub that will crack or stain in a few years. Whether you’re looking for a low-threshold walk-in shower or a deep soaking tub, we can help you find the perfect fit for your home and your budget.
Stop scrubbing and start enjoying your bathroom again.
Jayden Chuppe is the General Manager and Owner of The Bathroom Store, North Dakota’s premier bathroom remodeling specialist. With nearly two decades of experience in the home improvement industry, Jayden has built a reputation for excellence, overseen by his commitment to quality craftsmanship and innovative design. From tub-to-shower conversions to full-scale renovations, Jayden ensures that every project at The Bathroom Store meets the highest standards of durability and aesthetics. His goal is to help North Dakota homeowners transform their outdated bathrooms into functional, beautiful sanctuaries they can enjoy for a lifetime.
