By the Weather Shield Roofing team · Published October 14, 2026
The short answer
- Most "fiberglass roofs" on the Grand Strand are corrugated see-through panels over a porch, patio, carport or pool area. Many of them are really vinyl (PVC) or polycarbonate, not fiberglass, and the difference changes the fix.
- One cracked panel, a few loose screws or a leak at the house wall can usually be repaired. A roof that is yellowed, brittle or shedding glass fibers all over is at the end of its life, and patching it buys little time.
- The usual replacements are polycarbonate panels (if you want light through the roof) or metal panels (if you want a solid, longer-lasting roof). Either one has to suit the frame's slope and support spacing.
- TUFTEX, one of the big panel brands, does not recommend its panels as the main roof of a house or laid over an existing roof. If your porch roof ties into the house roof, it needs a real roof system.
- A walkable fiberglass roof deck is a roof over a room. A flaking top coat can be recoated, but leaks in several places or wet, soft boards mean the deck has to be redone, and water standing on it means the slope is too flat.
- Horry County lists permit requirements even for detached structures under 400 square feet, and its roof covering letter points to the high-wind rules in the 2021 South Carolina Residential Code.
The panel makers' numbers
1:12
minimum slope for TUFTEX panels
1 inch of rise per foot. The maker says they perform best at 2:12 or steeper.
24 in / 36 in
maximum support spacing
24 inches apart for TUFTEX vinyl panels, 36 inches for TUFTEX PolyCarb.
125°F
surface heat limit for clear vinyl
Clear and translucent vinyl panels are not recommended where surface temperatures can go higher, or where UV is high.
From the TUFTEX installation guide (Palram Americas, 2024). Other brands set their own limits; follow the sheet for the panel you buy.
Which fiberglass roof do you have?
"Fiberglass roof" covers four different things, and only some of them are a roofer's job. Work out which one you have before you call anyone.
Corrugated panel roof (porch, patio, carport, pool area)
Wavy, usually see-through or tinted sheets screwed to wood or metal cross supports. This is what most people on the Grand Strand mean by a fiberglass roof, and it is what most of this guide covers.
Fiberglass flat roof or walkable roof deck
A solid, seamless resin surface over plywood, sometimes called GRP. It is common in the UK, which is why so many repair videos online are British. On a beach house, a surface that looks like this may also be a coated membrane over plywood, so have it identified before anyone quotes a repair. Decks have their own section below.
Asphalt shingles with a fiberglass mat
Many asphalt shingles are built on a fiberglass mat, so a shingle roof is sometimes listed as "fiberglass". That is a normal shingle roof, and shingle repair rules apply.
RV, camper or boat roof
A one-piece fiberglass RV or boat roof is a job for an RV or marine repair shop, not a roofing contractor.
Panel makers sell these sheets for exactly the first kind: VALTO Engineered Materials lists its Sequentia translucent corrugated panels as "ideal for patios, pool enclosures, carports, decks and more", and TUFTEX names deck covers, sun porches, carports and patio covers. If yours is a shingle roof, start with our shingle types guide.
Is it really fiberglass? Fiberglass, vinyl and polycarbonate
Many corrugated panels called fiberglass are something else. The difference matters because each material has its own support spacing, heat limit and life on the coast.
Real fiberglass (FRP)
Glass strands are set in resin. As the surface weathers, the fibers come up through it and trap dirt, which glazing makers call "fiber bloom": the panel looks fuzzy, chalky or streaked and lets less light through.
Vinyl (PVC)
Sold widely for patio covers and carports. TUFTEX's own guide limits clear and translucent vinyl to milder weather and says it is not recommended where UV is high or the panel surface can pass 125°F.
Polycarbonate
Clearer, tougher plastic, usually with a UV-protected side that must face up. TUFTEX tells buyers in hot, humid places to choose its PolyCarb panels. SUNTUF polycarbonate panels carry a manufacturer warranty on light transmission and hail.
Sources: Crystal Structures (a polycarbonate glazing company) on fiber bloom; TUFTEX on vinyl heat limits and PolyCarb; SUNTUF on its warranty.
Why panel roofs fail on the Grand Strand
The panel makers' own instructions point to the usual weak spots: sun, fastening, slope, support spacing, laps and heat.
Sun and UV
Fiberglass panels "will develop a yellow hue" from UV exposure, according to a metal roofing supplier that sells them, and fiber bloom dulls them further. On the coast the sun works on these panels all year.
Screws driven too tight, or no washers
Panels grow and shrink with heat. TUFTEX says to pre-drill every hole oversized (5/16 inch with its own fasteners), use EPDM-washered screws, fasten on the crowns of every other corrugation and never overtighten. Cracks that start at screw holes are the classic sign this was skipped.
Too flat
TUFTEX panels need at least 1 inch of fall per foot, and SUNTUF at least 1½ inches per foot. Below that, water sits at the laps and finds its way in.
Supports too far apart
Vinyl panels need cross supports no more than 24 inches apart and TUFTEX PolyCarb no more than 36 inches. Wider spacing lets panels sag, flex in wind and crack.
Laps and the house wall
Side laps overlap one corrugation and end laps up to 4 inches, sealed. TUFTEX itself warns that lap adhesive "does not guarantee a waterproof seal". The joint where the panel roof meets the house needs real flashing tucked under the siding.
Heat and condensation underneath
TUFTEX says covered structures need ventilation to control condensation, and that panels should not sit directly on dark rafters, which build heat. Drips under a roof that is not cracked are often condensation.
Sources: Western States Metal Roofing on yellowing; the TUFTEX guide on fastening, slope, supports, laps and ventilation; the SUNTUF guide on its 1½-inch minimum slope. For how slope is measured, see our minimum roof pitch guide or the roof pitch calculator.
Repair or replace
A repair usually holds when
- One or two cracked or holed panels, with the rest still flexible and clear
- Leaks at screws that are loose, overtightened or missing washers
- A leak only where the panel roof meets the house wall
- A lap that has opened up, on a roof with enough slope
Replacement makes more sense when
- Yellowed, cloudy or fuzzy panels across the whole roof
- Panels that crack when pressed or around many screw holes
- Rot or rust in the rafters or cross supports
- A slope flatter than the panel maker's minimum, so water sits
- A panel roof that ties into the main house roof and leaks at the joint
Do not climb onto the panels to look. Palram's SUNTUF instructions say never to walk on the sheets, and to lay a board across at least three rafters to spread the load. If water is coming in now, our temporary leak guide covers safe stopgaps from the ground and inside.
What to replace it with
Polycarbonate panels
Keeps the light-through look. Check that the frame meets the new panel's support spacing and slope, and that the UV side faces up. Palram's SUNTUF warranty only applies when its installation instructions are followed, including purlin spacing, EPDM washers (never PVC), screw spacing and roof pitch, and it covers the price of the panels, not labor.
Metal roof panels
A solid roof that blocks the sun and handles coastal weather. Corrugated or exposed-fastener metal is the closest match to an existing panel frame; standing seam is a bigger job that suits a roof tied into the house.
A full low-slope or shingle roof
When the porch roof is part of the house roof, panels are the wrong product. TUFTEX states its panels "are not recommended as the primary roofing for residential or commercial buildings" and should not be laid "over existing roofing".
For the metal options side by side, see standing seam vs corrugated metal. For a porch roof that is part of the house, see flat roof replacement. Sources: SUNTUF warranty and the TUFTEX guide.
Fiberglass roof decks and balconies
A walkable fiberglass (GRP) deck or balcony over a room is a roof first and a deck second. When it fails, the water ends up in the ceiling below, so it needs a different answer from a panel roof.
Signs a fiberglass deck is failing
- Cracks or splits in the fiberglass surface
- The top coat flaking or peeling away from the layer under it
- Water standing on the deck long after rain
- Stains, drips or bubbling paint on the ceiling under the deck
- Spots that feel soft or springy underfoot, which can mean water has reached the boards underneath
Recoat, overlay or redo
Only the top coat is flaking
Resin Library's repair guide says to sand back to the fiberglass layer, check it for defects, repair what is found and apply a new top coat. This is what most people mean by recoating a fiberglass roof.
Surface defects all over
The same guide says the whole surface should be sanded back and given a new fiberglass layer and a new top coat, not spot repairs.
Worn but not leaking
The guide says an overlay, a new deck covering laid over the old one, is generally preferable to tearing it off.
Leaking in several places, or for a long time
Where the leaks have caused damage inside, the guide says a full replacement is required. It warns that moisture left in the structure can make the inner materials mold and rot, so wet boards come out.
Water standing on the deck
The 2021 South Carolina Residential Code requires built-up, modified bitumen, thermoplastic single-ply and liquid-applied roofs to have a design slope of at least 1/4 inch per foot (2 percent). Duradek, a maker of walkable vinyl deck membranes, says its decks should ideally slope 2 percent to get rid of ponding water. Water that sits on a fiberglass deck for long after rain means the deck is flatter than that, and fixing the slope is part of the job, not just the surface.
What to replace a failed deck with
A walkable vinyl (PVC) deck membrane
Made for decks people walk on. Duradek recommends 5/8-inch tongue-and-groove untreated plywood under its vinyl, a slope of ideally 2 percent, and an authorized Duradek installer. It says standing water will not affect the vinyl's waterproofing but may discolor it early.
A new fiberglass deck
Stripped back to sound, dry boards and laid again, as in the Resin Library guide. It keeps the look, but the slope and the boards underneath still have to be right.
A low-slope roof
If nobody needs to walk on it any more, a low-slope roof system at the code's 1/4 inch per foot is an option. See our flat roof replacement page for how those roofs are built.
Questions to ask whoever inspects the deck:
- Is the surface fiberglass, or a coating or membrane that looks like it?
- Are the boards underneath dry and solid, and how was that checked?
- What is the slope, and does it meet 1/4 inch per foot?
- Where exactly is water getting in: the surface, a seam, the wall, the door or the drain?
Sources: Resin Library (a guide by Strandek's managing director) on repairing fiberglass roofs; the 2021 South Carolina Residential Code, Chapter 9 on low-slope roof slopes; Duradek on deck slope, plywood and ponding.
Permits in Horry County
- Horry County Code Enforcement publishes permit requirements for a detached structure less than 400 square feet: an application, a scope of work, a site plan drawn to scale, and owner and contractor authorizations. Small does not automatically mean no permit.
- The county's roof covering letter asks the owner or contractor to certify that the roof covering was installed to the manufacturer's instructions and, for high wind areas, to the 2021 South Carolina Residential Code. That is one more reason to follow the panel maker's fastening rules. Our SC wind zone guide explains the coastal wind rules.
- Call Horry County Code Enforcement at 843-915-5090 (1301 Second Avenue, Conway) before work starts. Inside a city's limits, that city's building department may issue the permit instead.
What drives the cost
We do not publish prices, because two panel roofs of the same size can need very different work. These are the things that move a quote:
- Roof area, and whether only some panels or the whole roof is replaced
- Which panel or metal you choose
- The frame: whether rafters and cross supports are sound and spaced for the new panels
- Whether the slope has to be raised to meet the maker's minimum
- Flashing where the roof meets the house
- A permit, if the job needs one
- Getting to the roof and hauling the old panels away
What a good inspection checks
Whoever looks at your panel roof should identify the panel material, measure the slope, check the rafters and cross supports against the maker's spacing, look at how the panels were fastened and lapped, and trace the flashing where the roof meets the house. Only then can anyone say whether to repair, re-panel the frame, or put a real roof on it.
Weather Shield Roofing offers a free roof inspection and installs metal roofing and low-slope roof systems across Myrtle Beach, Horry County and Georgetown County, and handles leak repairs through our roof repair service. When you call, tell us it is a panel roof and what it covers, so we can say up front whether it is a job for us.
Questions about fiberglass roofs
Can a cracked fiberglass roof panel be repaired?
Usually, if only one or two panels are cracked and the rest are still flexible and clear. The damaged panel is replaced, the screws reset with washered fasteners, and the laps resealed. If the whole roof is yellowed, brittle or fuzzy with exposed fibers, patching buys little time and replacement is the better spend.
Why is my fiberglass porch roof turning yellow?
Ultraviolet light. Fiberglass roof panels yellow with sun exposure, and as the surface wears the glass fibers come up and trap dirt, which makers call fiber bloom. On the coast the sun works on these panels all year, so yellowing is a sign of age, not just dirt.
Is my roof fiberglass, vinyl or polycarbonate?
Many corrugated panels called fiberglass are vinyl (PVC) or polycarbonate. Fiberglass shows glass strands as it weathers and can look fuzzy or chalky. Polycarbonate is usually clearer, tougher and has a marked UV side. If you are not sure, have it identified before ordering replacement panels, because each needs different support spacing.
What should replace a fiberglass patio or carport roof in Myrtle Beach?
Polycarbonate panels if you want light to come through, or metal panels if you want a solid roof that blocks the sun. TUFTEX tells buyers in high-heat, high-humidity areas to choose its PolyCarb panels over vinyl. If the roof is attached to the house roof, use a real roof system instead of panels.
How long does a corrugated fiberglass roof last?
Stabilit America, a maker of fiberglass and polycarbonate panels, says fiberglass roof panels can last 20 to 30 years or more with proper installation and maintenance, and that panels become brittle over time when exposed to UV without protective coatings. On the coast, yellowing, fuzzy fibers or cracking around the screws mean the roof is near the end of that life.
What should seal the laps on a corrugated panel roof?
TUFTEX says to seal all side and end laps with a silicone sealer, vinyl adhesive or PVC cement, overlapping one corrugation on the sides and up to 4 inches at the ends. It also warns that adhesives do not guarantee a waterproof seal, so slope, fastening and wall flashing matter more than the sealant.
How do you recoat a fiberglass roof?
On a solid fiberglass roof or deck, Resin Library's repair guide says to sand back to the fiberglass layer, check it for defects, repair what is found and apply a new top coat. If defects cover the whole surface, the whole roof is sanded back and given a new fiberglass layer and top coat. A recoat does not fix wet or rotten boards underneath, so those are checked first.
Why is water pooling on my fiberglass roof deck?
Usually because the deck is too flat. The 2021 South Carolina Residential Code requires low-slope roofs such as built-up, modified bitumen, thermoplastic single-ply and liquid-applied roofs to slope at least 1/4 inch per foot, and Duradek says its vinyl decks should ideally slope 2 percent to get rid of ponding. Fixing pooling means fixing the slope, not just the surface.
Can new panels go over the old fiberglass roof?
TUFTEX says not to overlap or apply its panels over existing roofing. Old panels should come off so the frame, fasteners and flashing can be checked and the new panels fastened as the maker requires.
Do I need a permit to replace a fiberglass carport or porch roof in Horry County?
Ask Horry County Code Enforcement at 843-915-5090 before work starts. The county lists permit requirements even for detached structures under 400 square feet, including an application, a scope of work and a site plan. Its roof covering letter asks for certification that the roof was installed to the manufacturer's instructions and, for high wind areas, the 2021 South Carolina Residential Code. Inside a city's limits, that city's building department may handle the permit instead.
Can I walk on a fiberglass or polycarbonate roof to clean or fix it?
No. Panels are not made to carry a person's weight. Palram's SUNTUF instructions say never to walk on the sheets and to lay a board across at least three rafters to spread the load.
Who fixes a fiberglass RV, camper or boat roof?
An RV or marine repair shop. A one-piece fiberglass RV, camper or boat roof is a different product from a panel roof on a building. This guide is about fiberglass panel roofs and roof decks on homes and buildings.