Your fiberglass pool is one of the best investments you can make for your Inland Empire home. Durable, low-maintenance, and beautiful, until something goes wrong. A crack in the shell, fading gelcoat, or stubborn stain can make you wonder if you’re looking at a massive repair bill. The good news: many fiberglass pool problems are fixable, and some you can handle yourself. We’ve spent 25 years fixing these pools across the Inland Empire, and we’ve seen just about every damage pattern you can imagine. This guide walks you through what breaks, how to know if it’s a DIY job or time to call the crew, and what you can expect to pay.

What Makes Fiberglass Pools Different

Fiberglass pools are built from multiple layers: a structural laminate of fiberglass cloth and resin, a core layer for strength, and a smooth topcoat of gelcoat that seals everything and gives your pool its color and shine. That gelcoat is your pool’s first line of defense against UV, chemicals, and weather. In the Inland Empire, where our sun is relentless and temperatures swing from hot days to cool nights, that gelcoat takes a beating. Understanding what you’re dealing with helps you spot problems early and know which repairs matter and which ones are cosmetic.

Common Fiberglass Pool Damage You’ll Encounter

Osmotic Blistering: The Silent Threat

Osmotic blistering is the damage nobody sees coming. It happens when water seeps into the fiberglass laminate through tiny gaps in the gelcoat. Once it’s inside, it breaks down the resin, and pressure builds up until small blisters form on the pool surface or walls. You’ll notice them as tiny bumps or raised areas, sometimes no bigger than a pea, sometimes clusters of them. In the Inland Empire heat, osmotic blistering accelerates because the temperature swings cause expansion and contraction that weakens the gelcoat further.

Blistering is not a quick fix. If you catch it early and it’s just a handful of small blisters in one area, you might grind them out and patch them with fiberglass repair compound. But if it’s widespread, you’re looking at professional refinishing or a full recoat, which is what we usually recommend.

Spider Cracks and Fine Fractures

These are exactly what they sound like: thin, web-like cracks that spread across the gelcoat surface. Unlike structural cracks, spider cracks don’t go deep into the fiberglass. They’re cosmetic but annoying. They happen from UV damage, settling of the pool structure, or repeated freeze-thaw cycles (which we don’t get much of in the Inland Empire, but seasonal temperature swings can contribute). You can fill spider cracks with gelcoat repair putty or epoxy filler, sand them smooth, and re-seal. It’s a weekend DIY job if you’re comfortable with basic epoxy work.

Structural Cracks: When You Need Professional Help

Structural cracks are different. These go deep into the fiberglass shell, not just the gelcoat layer. They’re usually the result of impact (heavy equipment, rocks, or settling), freeze damage in other climates, or a manufacturing defect that shows up over time. You’ll notice them as cracks you can actually see width in, sometimes with slight separation of the edges. Water might seep out around the crack, or you might notice the pool losing water faster than normal evaporation would account for.

If the crack is small and in a low-stress area, we can patch it from inside the pool with marine-grade epoxy and fiberglass tape. Larger structural cracks or cracks in the deep end near the main drain are a different story. These need full professional repair to ensure the patch holds under pressure.

Gelcoat Fading and Chalking

The Inland Empire sun does things to gelcoat. Your pool’s color fades, and the surface gets dull and chalky. This is UV damage, and it’s inevitable. Every pool gets it eventually. It’s not a structural problem, but it makes your pool look tired. You can slow it down with good UV-blocking pool covers and regular chemical balance, but you can’t stop it completely. When the fading bothers you, a professional can buff and polish the surface, apply a UV protective sealer, or do a full gelcoat refinish if you want the pool to look new again.

Surface Stains and Discoloration

Mineral stains, rust spots, and algae marks happen in every pool, especially in the Inland Empire where our water tends toward hard minerals. Most of these are just algae or mineral deposits that come off with proper brushing, chemical treatment, and balancing. But some stains are actually damage. Rust from embedded metal particles, or permanent staining from exposure. Deep stains in gelcoat sometimes need to be sanded and polished out, or patched with fresh gelcoat if the damage is deep enough.

DIY Fiberglass Pool Repairs: What You Can Actually Do

Patching Small Cracks and Holes

If you’ve got a small crack or chip in the gelcoat that doesn’t go all the way through the fiberglass, you can patch it yourself. Here’s the process:

1. Drain the pool if the damage is above the waterline, or if below the waterline, drain enough so the damaged area is dry and exposed.
2. Use 120-grit sandpaper to rough up the area around the damage, creating a surface about 2 inches wider than the crack in all directions. This helps the epoxy bond.
3. Clean away all dust with a tack cloth or damp rag, then let it dry completely.
4. If the crack goes deeper than surface deep, use a rotary tool with a small grinding bit to widen the crack slightly into a V-groove. This gives the patch material more surface area to grip.
5. Mix two-part marine epoxy or polyester resin according to package directions (temperature matters: warmer is better for curing, but don’t apply in direct sun). Add gelcoat powder to match your pool color if you want a smooth finish.
6. Pack the crack with the epoxy using a putty knife, overfilling slightly.
7. Smooth it level once it’s semi-set, and let it cure fully per package directions (usually 24-48 hours).
8. Sand smooth with 220-grit, then 400-grit sandpaper.
9. Apply two coats of pool-safe UV protective sealer or gelcoat topcoat.

This works best on cracks under about 1/8 inch wide. Anything wider or longer than a few inches should get professional attention to make sure the underlying fiberglass isn’t compromised.

Addressing Surface Stains

For algae stains and mineral deposits, start with the chemical approach: brush thoroughly, shock the pool if algae is present, and balance the pH and alkalinity. If stains persist, try a stain remover designed for fiberglass pools (avoid aggressive acids unless the stain is really stubborn). For rust spots from embedded metal particles, you can sometimes lift them out with a small tool or grinding bit on a rotary tool, then patch the tiny hole left behind.

Permanent staining or deep discoloration usually means the stain has bonded with the gelcoat itself. You can try carefully sanding the area with fine-grit (220-400) sandpaper, but if the stain goes deeper than the surface layer, you’ll need professional refinishing.

Cleaning and Sealing the Gelcoat

Regular maintenance prevents a lot of damage. Clean your pool’s walls monthly with a brush and skimmer to prevent algae and staining. Every season, consider applying a UV protective sealer designed for fiberglass pools. This slows the fade and chalking that Inland Empire sun causes. Products like Starbrite or Meguiar’s fiberglass protectant are affordable and easy to apply with a pad or cloth. This is 100% a DIY job and takes maybe an hour.

Refinishing Options: Bringing Your Pool Back to Life

When surface damage adds up (fading, chalking, small cracks, stains), you have options below the level of a full recoat.

Polishing and Sealing

If the damage is mostly cosmetic (fading, chalking, minor stains), professional polishing can restore gloss and color. We use an electric buffer with fine-grit pads to gently restore the surface, then apply protective sealer. This costs less than a full recoat and makes your pool look new again. It’s not permanent. You’ll need resealing in a few years, but it’s a smart middle-ground fix.

Partial Gelcoat Repair

If one wall or one section is more damaged than the rest, we can sometimes repair just that area. We grind out the damaged gelcoat, prep the fiberglass underneath, and apply fresh gelcoat to match. This works if the damage is isolated and the surrounding gelcoat is still in decent shape. Color matching can be tricky on older pools because the original color has faded, but we have tricks to blend it.

Full Gelcoat Refinish

This is the big one. We drain the pool completely, sand the entire interior surface to bare fiberglass, inspect for any hidden damage, and spray-apply multiple layers of fresh gelcoat. We finish with UV-protective topcoat. The pool looks brand new, all the old surface damage is gone, and you get a warranty on the work. This is a multi-week project and costs anywhere from $4,000 to $12,000 depending on pool size and the quality of gelcoat you choose, but it’s worth it if your pool is structurally sound but cosmetically worn out.

Professional Repairs: When to Call the Crew

Some jobs are beyond DIY, not because they’re hard, but because the equipment or materials you need are specialized and expensive. Structural repairs involving the fiberglass laminate, major cracks, waterline problems, or full refinishing should be handled by professionals who have the equipment, materials, and warranty backing to do it right.

We use Hayward repair systems for most structural work because they’re proven reliable. For gelcoat, we stock Pentair and Jandy-compatible materials to match just about any pool color. If your pool uses brand-specific equipment or finishes, let us know upfront so we can source the right materials.

Signs it’s time to call us:
– Structural cracks wider than 1/8 inch or longer than a few inches
– Cracks at seams or stress points (where walls meet floor, near drains)
– Active leaking that you can’t locate or patch
– Blistering that covers more than a small area
– Any damage below the waterline that you can’t safely access
– Fading and staining so severe you’re embarrassed to use the pool

Inland Empire Factors: Heat and UV

The Inland Empire throws specific challenges at pools that other regions don’t. Our summer temperatures can spike over 110 degrees, and the sun is unrelenting. This means gelcoat degrades faster here, thermal stress on the fiberglass is higher, and water chemistry swings more dramatically. We’ve seen pools in the Inland Empire develop cosmetic issues 2-3 years faster than the same pools elsewhere.

Mitigation strategies: Use a UV-blocking pool cover when the pool isn’t in use. Keep water chemistry balanced. Acidic water and high chlorine levels accelerate gelcoat breakdown. Run the filter in early morning or evening to avoid adding heated water in peak heat. Brush the pool weekly to prevent algae buildup that holds moisture against the gelcoat. And if your pool is in direct afternoon sun all year, plan on refinishing gelcoat every 8-10 years instead of the typical 12-15 years you’d expect elsewhere.

Cost Expectations

Small patches and DIY repairs: $50 to $500 for materials, depending on whether you need special tools.

Professional crack repair (small to medium, structural): $300 to $1,500 per repair, depending on location and depth.

Polishing and sealing the whole pool: $1,500 to $3,000 depending on size.

Partial gelcoat repair (one wall or section): $2,000 to $5,000.

Full gelcoat refinish: $4,000 to $12,000 depending on pool size (smaller pools cost less per gallon, larger pools scale up).

Emergency leak repair (after-hours or emergency service): Add 50-75% to the standard rate, but sometimes it’s worth it to avoid losing the whole pool to damage.

We’ve seen pools drain themselves in a few weeks if a structural crack isn’t addressed. In the Inland Empire heat, that means the fiberglass can start to delaminate and warp. Don’t wait on structural problems.

Fiberglass vs. Other Pool Types

Fiberglass is more durable than plaster and requires less chemical treatment than vinyl, but it’s not invincible. Plaster pools chip and stain more easily but are cheaper to refinish initially. Vinyl pools are soft and prone to tears but are the cheapest option. Fiberglass sits in the middle: higher upfront cost, but lower maintenance and longer-term durability if you take care of the gelcoat.

If you’re deciding between repairing your current fiberglass pool or upgrading, fiberglass almost always wins on value if the structure is sound. Refinishing a pool costs half what converting to plaster or vinyl would, and you’re working with proven fiberglass technology that’ll last another 20+ years.

When to Replace vs. Repair

Replace your pool if: The shell has major structural damage (large cracks, significant settling), multiple delamination areas, or the bottom is warping or separating. These aren’t fix-it-once problems. They’ll keep failing.

Repair your pool if: The structure is sound but the surface is worn, or you have isolated cracks and damage. A solid fiberglass shell with cosmetic problems is worth fixing every time.

We can inspect your pool and give you an honest assessment. Sometimes repair isn’t worth it, and we’ll tell you that. But most of the time, we can get your pool back to solid for a fraction of what replacement costs.

Common Fiberglass Pool Questions

Can I patch a leaking fiberglass pool myself?

Small leaks in accessible areas, yes. If you can locate the crack and reach it (above the waterline or after draining), you can patch it with marine epoxy and fiberglass tape. If the leak is below the waterline in the deep end or you can’t find where it is, call us. We have leak detection equipment and can patch underwater if needed.

How long does a fiberglass pool last?

A well-maintained fiberglass pool shell lasts 25-30 years or more. The gelcoat surface typically needs refreshing every 10-15 years, depending on Inland Empire sun exposure (ours is closer to 10-12 years). Plumbing and equipment may need replacement sooner, but the shell itself is the longest-lasting pool type available.

Is it worth refinishing an old fiberglass pool?

Absolutely, if the structure is sound. A 15-year-old fiberglass pool with a faded, stained surface can be refinished for $4,000-8,000 and come out looking like new. A new pool costs $30,000-60,000. The math is easy.

What causes osmotic blistering, and can I prevent it?

Blistering happens when water seeps into the fiberglass laminate through tiny cracks in the gelcoat. It’s usually a manufacturing defect or damage that wasn’t sealed properly. Prevention: keep the gelcoat sealed with UV protectant, address cracks and chips immediately, and maintain proper water chemistry. If blistering shows up on a newer pool, it’s likely a warranty issue.

Can I use a pressure washer on fiberglass?

Carefully. Use low pressure (under 1,500 PSI) and keep the nozzle at least a foot away from the surface. High pressure can damage the gelcoat and push water into microcracks. A soft brush and mild detergent are safer and just as effective.

Do I need special products for fiberglass pools?

Your basic pool chemicals (chlorine, pH adjusters, alkalinity boosters) are the same for any pool. But for cleaning and protecting the surface, fiberglass-specific products (like Starbrite or Meguiar’s) are worth the small extra cost. They’re formulated to be gentle on gelcoat and include UV protectants that plaster-pool products don’t.

What’s the best way to prevent fading in the Inland Empire?

Use a pool cover when not in use, keep the water chemistry balanced, and apply UV-protective sealer annually. Some people also use pool shade structures (shade sails or umbrellas) if they’re in an area that gets afternoon sun all year. We’ve seen pools with shade maintain color noticeably better than uncovered pools in the same neighborhood.

How to Pick a Fiberglass Pool Repair Contractor

Not every pool company is comfortable with fiberglass. Plaster repair is a different skill set, and a contractor who’s great with plaster can still botch a gelcoat job. A few things to check before you sign anything.

Ask how many fiberglass pools they finish or repair in a year. A real fiberglass specialist will be doing this work weekly. If the answer is “a few a season,” you’re probably their training pool. Ask which gelcoat product they spray and whether they color-match on site or order pre-tinted. A shop that color-matches in the truck has done this enough to know what works in our climate.

Get the warranty in writing. A reputable fiberglass refinish should carry at least a one-year workmanship warranty, and quality gelcoats come with a 5-year manufacturer warranty. If a contractor pushes back on putting that in writing, walk. Also ask about acetone tests on the existing gelcoat before they quote a refinish, since old gelcoat can have surface contamination that ruins adhesion if it’s not addressed up front.

Finally, check that they pull permits for any structural work. In Riverside and San Bernardino counties, structural pool repairs may need permits depending on scope. A licensed contractor who handles permits is a contractor who plans to be in business next year.

Your Inland Empire Pool is Worth Fixing

We’ve built our 25-year reputation on fixing pools right, the first time. A fiberglass pool in good structural condition is an asset worth maintaining. Whether you’re patching a small crack yourself or we’re handling a full refinish, the goal is the same: get your pool back to something you’re excited to use instead of worried about.

If you’ve got damage you’re unsure about, call us for a free estimate. We’ll show you what it is, explain your options, and give you an honest assessment of whether it’s DIY material or time to bring in the crew. Same-week service, fair pricing, and the kind of straight-talking repair advice you’d get from a neighbor who’s been doing this for two and a half decades.

Contact Pool Spa Repairs today. Call (909) 330-4730 for your free estimate.