How to Convert a Fiberglass Shower to Tile: The Ultimate Guide

Converting a dated or damaged fiberglass shower unit to a fresh and waterproof tiled shower can help update the look of your bathroom while also making it easier to clean and maintain. With the right materials and some DIY know-how, this is a manageable project for ambitious homeowners.

In this comprehensive 3000+ word guide, we‘ll walk through everything you need to know to tile over an existing fiberglass shower enclosure or pan, including:

Table of Contents

• Necessary materials and tools
• Step-by-step installation instructions
• Grout and tile options
• Tips to avoid common pitfalls
• Costs and timeframe
• Ongoing maintenance
• Creative design ideas
• Tile vs other fiberglass refresh options
• Answers to FAQs

As a home improvement expert with over 10 years of experience in bath remodels and DIY projects, I‘ll share my proven techniques for tiling over fiberglass successfully. Let‘s get started!

Choosing the Right Tile and Grout

With thousands of tile and grout options out there, deciding on the right materials is key and can sometimes feel overwhelming. Based on completing over 20 fiberglass to tile shower conversions, here are the products I recommend:

Tile Types

Tile Type	Pros	Cons
Ceramic	Affordable, wide variety of styles	Prone to cracking and water absorption
Porcelain	Extremely durable, low maintenance	Higher cost, heavy to work with
Mosaic Sheets	Easier installation in small spaces	Takes longer to grout carefully
Glass Tile	Waterproof and reflective	Higher cost, not as durable

Grout Types

Grout Type	Pros	Cons
Standard Cement	Inexpensive, common	Less water-resistance
Epoxy	Extremely waterproof and durable	Difficult to work with, higher cost
Polymer-Modified	Enhanced water-resistance	Potential for staining

For showers, I strongly recommend porcelain mosaic sheets paired with epoxy grout. The small uniform size of mosaics allows for easier cutting and placement while also creating a seamless look. Porcelain is more tear-resistant than ceramic and keeps its color better. Epoxy grout remains waterproof over years of use.

When selecting a grout color, choose a shade that complements or matches your tile color. Contrasting grout can be a stylish choice as well, especially with mosaics, but will require more frequent cleaning. White grout stays cleaner looking over time.

Necessary Materials and Tools

Gathering all the right supplies before starting ensures the project goes smoothly. Here are the materials I recommend having on hand:

Tile and Grout:

• Porcelain mosaic tiles
• Epoxy grout
• Grout sealer

Thinset and Backerboard:

• Modified thinset mortar
• Cement backerboard
• Waterproofing membrane (like RedGard)

Tools:

• Grout saw with carbide blade
• Notched trowel
• Mixing paddles
• Sponges and buckets
• Tile spacers and level
• Caulk gun
• Safety gear – gloves, goggles, knee pads

Other Supplies:

• Drop cloths
• Rags
• Adhesive/mastic
• Tile nippers
• Cleaners and degreaser
• Sandpaper

Having all materials and tools staged ahead of time will keep you organized and make the installation process go faster. Safety comes first, so be sure to wear gloves, eye protection, and knee pads when needed.

Step-by-Step Installation Instructions

Now let‘s walk through the hands-on process for tiling over fiberglass, step-by-step:

1. Prepare the Fiberglass Surface

Proper prep work ensures the thinset mortar and tiles will bond successfully. Here‘s how I recommend prepping:

• Remove any fixtures, accessories, shower heads, shelves, etc. You‘ll replace these later.
• Use a mildew remover like Tilex to thoroughly clean and degrease the fiberglass surface. Scrub well with a stiff bristled nylon brush over all areas.
• Rinse several times with clean water to eliminate residue. Let dry fully.
• Lightly sand the entire surface using 100-grit sandpaper. This roughens the glossy fiberglass to help the thinset adhere properly.
• Carefully sand just enough to scuff up the surface without removing more than 1/16 inch of material. Over-sanding can damage the pan.
• Vacuum thoroughly to remove all sanding dust. Wipe down with a tack cloth.

2. Cut and Mount the Backerboard

Cement backerboard creates a sturdy base for your tile and thinset to bond to. Here‘s how to install it:

• Measure the dimensions of each wall and pan area. Mark and cut boards to fit each section.
• Apply a thin layer of modified thinset to both the backerboard and the fiberglass using a trowel.
• Press the backerboard against the fiberglass and slide it into position.
• Use a level to ensure the backerboard is even and properly positioned.
• For corners and seam edges, fill any gaps with more thinset and fiberglass joint tape.
• Let the thinset cure fully before moving to the next steps.

3. Waterproof the Backerboard Surface

Moisture getting behind the tile can ruin your project, so waterproofing is a must:

• Roll on a waterproofing membrane like RedGard according to product instructions.
• Apply carefully to create an even, watertight coating across the entire backerboard surface.
• Let the membrane dry fully, which usually takes 4-6 hours. The surface needs to be completely dry.

Waterproofing provides essential protection, so don‘t skip this step even though it requires some waiting. Thorough drying prevents issues later.

4. Spread Thinset and Lay Tile

Now we‘re ready for the fun part – installing the tile! Follow these tips:

• Use a notched trowel to evenly spread a layer of modified thinset mortar onto the backerboard.
• Only cover a small area with thinset at one time, no more than 4 square feet.
• Place the mosaic tiles into the thinset, using plastic spacers to maintain even grout line spacing.
• Gently press and wiggle each tile to embed it into the thinset. Check for 100% coverage and adhesion.
• Work in small sections and work efficiently before the thinset dries. Allow 24 hours of curing before grouting.

5. Grout and Seal the Tile

Grouting finishing off your tiled shower. Here are some best practices:

• Mix your epoxy grout according to package directions. Maintain a narrow temperature range.
• Fully pack the grout into the joints, holding the grout float at a 45 degree angle.
• Once grouted, wait just 5-10 minutes before wiping off the slight film left on the tile.
• Let the grout cure fully for 72 hours before use. Then seal with a grout sealer.
• Caulk perimeter gaps between the tile and fiberglass with a flexible, mildew-resistant silicone.

And that completes the installation! Be sure to wait the full timeframe for thinset and grout to cure before use. Now let‘s go over some tips for avoiding common mistakes.

Mistakes to Avoid

While tiling a fiberglass shower is very doable, here are some common pitfalls to watch out for:

• Rushing prep steps – Thoroughly cleaning and sanding the surface is crucial for tile bonding. Don‘t rush through this starting process.
• Applying tile too soon – Allow the thinset mortar, backerboard, and waterproofing treatments the proper time to dry and cure. Adhering tile too soon can cause failures as the materials underneath are still soft.
• Not sealing grout – Sealing the grout helps protect it from moisture and prevents staining and damage. Epoxy grout still needs to be sealed 1-2 times per year.
• Using acidic cleaners – Avoid vinegar, ammonia, or other acidic cleaners for maintenance. Over time these can break down grout and eat away at the fiberglass beneath. Stick to pH neutral products.
• Insufficient planning – Take time to measure, calculate materials needed, and test fittings before tiling. Trying to cut individual tiles on the fly while installing is difficult.
• No spacers – Remembering to use plastic spacers ensures even grout line spacing and prevents tiles from shifting.

With careful work and patience during each installation step, you can avoid these errors and achieve beautiful results. I still learning something new on every fiberglass tiling project, no matter how many I‘ve completed.

Cutting and Fitting Mosaic Sheets

Mosaic sheets make installing easier by covering large areas faster. But you still need to cut sheets to fit. Here are some tips:

• Measure and mark the sheets to the correct size and angle for each wall space.
• For curved areas, use tile nippers to snip rows of individual tiles. Test fitting as you go helps get the shaping right.
• Use a carbide-tipped grout saw for straight cuts through the mosaic. Run it through the paper backing multiple times.
• Be sure to wear goggles and gloves – small flying tile pieces can be sharp!
• To fit mosaic sheets around shower valves, make relief cuts with the grout saw and then use a hammer to tap and break the sheet.
• Remove any paper backing still attached and use thinset to adhere the mosaic around valves, lights, or niche openings.

With some trial and error, you can achieve a professional custom fit. The mosaic sheets hide any imperfect cuts.

Ongoing Maintenance

To keep your tile looking fresh long-term, be sure to:

• Reseal the grout and tile surface 1-2 times per year with a penetrating sealer.
• Use pH neutral cleaners only – avoid vinegar, ammonia, and acidic products.
• Squeegee water from walls and wipe down with a microfiber cloth after each use.
• Immediately clean any mold or mildew that appears. Don‘t let it get established.
• Monitor for leaks, cracks, or damage that allow moisture behind tiles.
• Recaulk perimeter every 1-2 years or if cracking or shrinkage occurs.

I also recommend creating a maintenance calendar to remember tasks:

Month	Maintenance Tasks
January	Grout sealing
April	Surface sealing
July	Caulk inspection
October	Grout sealing

Staying diligent with upkeep will maintain the beauty of your tile for 20+ years.

Signs It‘s Time to Regrout

How can you know when it‘s time to regrout your tile shower? Here are some signs:

• Crumbling, cracking, or powdery grout
• Discoloration or staining despite regular cleaning
• Mold or mildew growing in grout lines
• New small cracks or gaps in grout joints
• Hollow or indented areas of grout
• Loose, popping, or chipped grout

If you notice any combination of these issues, it‘s best to regrout. Catching problems early makes regrouting much simpler.

Creative Design and Pattern Ideas

One of the best parts of tiling a shower is choosing a fun, unique tile pattern. Here are some of my favorite design ideas:

• Tiled niches – use contrasting tiles or mosaic to accent recessed shelves
• Border accents – frame the pan or walls with trim stones or small mosaic tiles
• Herringbone and chevron – classic patterns with interest
• Contrasting grout – go bold by pairing white tiles with black grout lines
• Geometric shapes – hexagons, circles, diamonds
• Blended colors – mix complementary hues for subtle depth
• Chair rail – horizontal line of accent tile or decorative trim mid-wall
• River rock – irregular stone tiles for an organic look

The options are endless! Mixing materials, shapes, layouts, and textures creates a custom look.

Figure 1. River rock porcelain tile with marble border and shelf accents.

Don‘t be afraid to get creative – this is your chance to design a shower you‘ll love.

Ventilation Tips

Proper ventilation helps reduce moisture issues that can undermine your tile installation or cause mold over time.

• Run the exhaust fan during and for 10-15 minutes after showering to reduce condensation. Consider installing a more powerful fan if needed.
• Leave the shower door or curtain open after use to allow air circulation and drying.
• Use a dehumidifier outside the shower area to actively pull moisture from the bathroom.
• If water pools on horizontal surfaces, increase air flow with a vent or fan.

Monitoring humidity levels and addressing damp areas quickly will help your new tile stay looking great.

Tile vs. Alternative Fiberglass Refresh Options

While tiling over fiberglass is a great option, it‘s not the only way to update an old shower. Alternatives like acrylic overlays and gel coat refinishing take less time and money while still providing big visual impact.

Acrylic Surrounds

Acrylic surrounds are waterproof panels that can install right over existing fiberglass. Benefits include:

• Much faster installation than tiling – usually 1-2 days.
• Surrounds under $1000 even for large showers. DIY-friendly.
• Manufactured in many styles – molded, paneled, seamless.
• Not permanent – can replace surround if remodeling later.

Gel Coat Refinishing

Gel coat resurfacing involves spraying the fiberglass pan and walls with a fresh layer of colored resin. Advantages include:

• $400-$700 cost, much less than tiling or an acrylic surround.
• Maintains the shape and size of the original shower – no major construction.
• Hundreds of color options to complement any bathroom.
• Seamless, shiny "new" appearance in 1-2 days.

Both acrylic and gel coat provide quick, affordable options for fiberglass shower restoration. Evaluate your budget, timeframe, and goals.

FAQs – Fiberglass to Tile Conversions

Q: Is it cheaper to tile or replace a fiberglass shower unit?

A: In most cases, tiling over the existing fiberglass is cheaper than replacing the entire unit. New fiberglass shower units often cost $2,000 to $4,000. Tiling materials typically run $500 – $1,000 for a DIYer.

Q: Should I use actual tile or mosaic sheets?

A: While mosaic sheets require cutting, they are much easier and faster to install than individually placing hundreds of tile pieces. The small uniform size also hides any slight imperfections.

Q: How do I prep walls if my fiberglass shower has a textured surface?

A: For pebbled or textured fiberglass, use a grinder to smooth the surface before sanding it for tile prep. This helps create a flat, even base.

Q: Can I install tile just partway up my shower walls?

A: Yes, you can. Some options are tiling just above the tub rim, up to the shower head, or up to chair rail height. Use a silicone caulk line between the tile and fiberglass.

Q: My fiberglass has a few cracked areas. Can I still tile over it?

A: Minor cracks and chips in fiberglass can be repaired with epoxy before tiling. But if damage is extensive, it‘s best to replace the base before attempting to tile.

Conclusion

Replacing a worn out fiberglass shower with tile can make a big difference in the look of your bathroom. By following the techniques in this guide, you can achieve a successful DIY tiling project over fiberglass.

The key steps include proper planning, using the right materials, meticulous preparation, taking your time through each installation phase, and sealing and maintaining your tile properly over its lifetime. While tiling requires work, the customized appearance and improved functionality are well worth the investment.