Best Roofing Materials for Flat Roofs in Myrtle Beach: 2026 Guide

Every flat roof guide tells you material selection matters. But in Myrtle Beach, the stakes are significantly higher than what those generic guides describe. The coastal environment here creates a combination of stressors that accelerate material degradation and amplify the consequences of choosing the wrong system.

Rainfall: 50+ Inches Annually with Tropical Intensity

Myrtle Beach receives over 50 inches of rain per year — significantly above the national average of 30 inches. More importantly, much of this rain comes in intense tropical downpours that can drop 2 to 4 inches per hour during summer storms. Flat roofs are inherently more vulnerable to water because they rely on drainage systems rather than gravity and slope to move water off the surface. A flat roof material that cannot handle ponding water or has seams that degrade under constant moisture exposure will fail here faster than anywhere inland.

Proper flat roof drainage requires a minimum slope of 1/4 inch per foot and drainage capacity to handle at least 4 inches per hour during peak events. The material you choose must maintain watertight integrity even when water ponds temporarily during heavy downpours — because in Myrtle Beach, that happens regularly from May through October. For a deeper understanding of how flat roofs manage water, see our complete guide to the layers of a flat roof.

Salt Air: The Silent Material Destroyer

Properties within 5 miles of the ocean — which includes most of the Myrtle Beach area — are exposed to salt-laden air that accelerates corrosion and material degradation at 3 to 5 times the rate of inland environments. Salt air attacks metal fasteners, degrades adhesive bonds, causes chalking and surface deterioration on membranes, and corrodes flashing. Not all flat roof materials resist salt air equally. PVC and certain metals like aluminum handle it well. EPDM and standard steel fasteners are more vulnerable. The material comparison tables later in this guide rate every option for salt air resistance specifically.

Hurricane Wind Codes: 130+ MPH Design Requirements

South Carolina building code requires flat roofs in coastal Horry County to meet wind design criteria for 130 to 150 mph based on the property's specific wind zone classification under ASCE 7. This is not optional — it is code. The way a flat roof material is attached matters as much as the material itself. Fully adhered membrane systems (where the membrane is glued directly to the substrate) outperform mechanically attached systems (where fasteners hold the membrane down) in hurricane conditions. Gravel-ballasted systems — where loose stones hold the membrane in place — are prohibited in hurricane zones because the gravel becomes dangerous projectiles in high winds.

UV Exposure and Humidity

Myrtle Beach averages over 215 sunny days per year with intense southern sun that accelerates UV degradation on roof membranes. Combined with average humidity above 75%, you get an environment where moisture gets trapped under or within roofing systems, promoting mold growth, substrate deterioration, and adhesive failure. White reflective membranes like TPO and PVC handle this environment significantly better than dark-colored materials like EPDM, which absorb heat and contribute to higher cooling costs and accelerated aging.

TPO (Thermoplastic Polyolefin) has become the most widely installed flat roof membrane in the United States, and for good reason. It delivers an excellent balance of performance, energy efficiency, and value that makes it the go-to choice for most commercial and many residential flat roof projects in Myrtle Beach. For a comprehensive deep dive into this material, read our complete TPO roofing guide.

What TPO Is and How It Works

TPO is a single-ply roofing membrane made from a blend of polypropylene and ethylene-propylene rubber. It comes in large rolls that are laid across the roof deck and joined together using hot-air welding — a critical advantage for coastal applications. The welded seams create a bond that is actually stronger than the membrane itself, unlike adhesive-bonded seams that can degrade in high humidity. TPO is typically white or light-colored, which reflects solar radiation and reduces cooling costs.

TPO Coastal Performance

• Lifespan: 20 to 25 years with proper installation and maintenance
• Wind resistance: Excellent — fully adhered TPO systems can be rated for 120+ mph uplift resistance, meeting Horry County building code requirements
• Salt air resistance: Good — TPO resists salt air degradation well, though PVC edges it out in this category
• UV resistance: Excellent — the white reflective surface bounces back 80%+ of solar radiation, reducing cooling costs by 25 to 40% compared to dark membranes
• Ponding water: Good — TPO handles temporary ponding well, but like all flat roof systems, proper drainage design is essential
• Humidity performance: Excellent — hot-air welded seams are unaffected by high humidity during and after installation, unlike adhesive-dependent systems

Pros and Cons for Myrtle Beach

Best For

TPO is the best overall choice for commercial flat roofs in Myrtle Beach — hotels, retail centers, office buildings, and condos along the Grand Strand. It is also an excellent choice for residential flat roof sections where energy efficiency and hurricane resistance are priorities. If you are working within a budget and need proven performance in coastal conditions, TPO should be your starting point.

PVC (Polyvinyl Chloride) roofing membranes are the premium single-ply option for flat roofs, and they earn that position with superior chemical resistance and the best salt air performance of any membrane material. For properties near the ocean, PVC is the material that gives you the longest service life and fewest problems. For detailed lifespan data, read our guide on how long PVC roofing lasts in Myrtle Beach.

What Sets PVC Apart

PVC membranes are reinforced with polyester or fiberglass and contain plasticizers that keep the material flexible over decades of service. Like TPO, PVC seams are hot-air welded, creating permanent bonds stronger than the membrane itself. But PVC has two key advantages over TPO: significantly better chemical resistance (critical for restaurants, commercial kitchens, and industrial facilities) and superior resistance to salt air and coastal atmospheric conditions.

PVC Coastal Performance

• Lifespan: 25 to 30 years — the longest of any single-ply membrane in coastal environments
• Wind resistance: Excellent — fully adhered PVC systems meet and exceed Horry County wind code requirements
• Salt air resistance: Best in class — PVC shows minimal degradation from salt exposure even after 20+ years of coastal service
• Chemical resistance: Excellent — handles grease, animal fats, and chemical exposure that would damage TPO or EPDM
• UV resistance: Excellent — white reflective surface with built-in UV stabilizers
• Fire resistance: Superior — PVC is inherently fire-resistant without additional treatments

Why PVC Outperforms TPO Near the Ocean

For properties within 1 to 2 miles of the Atlantic Ocean, PVC has a measurable advantage over TPO. The salt air concentration in this zone is at its highest, and PVC's chemical composition resists salt-induced degradation better than TPO's polypropylene blend. In our experience installing both materials on oceanfront properties in Myrtle Beach, North Myrtle Beach, and Surfside Beach, PVC membranes consistently show less surface chalking, better seam integrity, and longer maintenance-free service periods than TPO in the same salt-heavy environment.

Pros and Cons for Myrtle Beach

Best For

PVC is the best choice for oceanfront commercial properties, restaurants and commercial kitchens (grease resistance), hotels and resorts within 2 miles of the beach, and any flat roof project where long-term durability in salt air justifies the premium cost. If your property is on or near Ocean Boulevard, PVC should be your first consideration.

EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber membrane that has been used on flat roofs for over 50 years. It is the most affordable single-ply option and has a proven track record in many climates. However, EPDM has specific limitations in coastal Myrtle Beach that every property owner should understand before choosing it.

What EPDM Is and How It Works

EPDM is a black (or white-coated) rubber membrane that comes in large sheets. Unlike TPO and PVC, EPDM seams are joined using adhesive tape or liquid adhesive rather than heat welding. This is a critical distinction for coastal applications. The adhesive bond is the weak point of any EPDM system, and high humidity environments like Myrtle Beach can compromise adhesive performance both during installation and over the life of the roof.

EPDM Coastal Performance

• Lifespan: 25 to 30 years in ideal conditions, but coastal salt air and UV exposure can reduce this to 18 to 22 years
• Wind resistance: Good when fully adhered, but adhesive-bonded seams are more vulnerable to wind uplift than welded seams
• Salt air resistance: Good for the membrane itself, but salt air accelerates adhesive degradation at seams
• UV resistance: Fair — black EPDM absorbs significant solar heat, accelerating aging and increasing cooling costs
• Energy efficiency: Poor for standard black EPDM — the dark surface absorbs heat instead of reflecting it, increasing summer cooling costs. White EPDM coatings are available but add cost
• Ponding water: Good — the rubber material handles ponding well

Coastal Limitations You Should Know

EPDM's biggest weakness in Myrtle Beach is its adhesive-bonded seam system. In our 75%+ average humidity, adhesive bonds are harder to establish correctly during installation and degrade faster over time compared to heat-welded seams. We have repaired numerous EPDM roofs along the Grand Strand where seam failure was the primary issue — and it almost always traces back to the adhesive, not the membrane itself.

The second concern is energy cost. Standard black EPDM can reach surface temperatures of 150 to 170 degrees Fahrenheit on summer afternoons in Myrtle Beach. That heat transfers into the building, driving up air conditioning costs significantly. For a commercial building with a large flat roof, this energy penalty can add up to thousands of dollars annually compared to a white TPO or PVC membrane.

Pros and Cons for Myrtle Beach

Best For

EPDM makes sense for budget-conscious residential flat roof projects, properties more than 5 miles from the ocean where salt air exposure is reduced, small flat roof sections like carports, covered patios, or additions, and situations where upfront cost is the primary constraint. For commercial flat roofs or properties near the coast, we recommend TPO or PVC instead.

Modified bitumen is a multi-layer asphalt-based roofing system that has been protecting flat roofs since the 1960s. It combines the proven waterproofing properties of asphalt with modern polymer modifiers that improve flexibility, UV resistance, and longevity. Modified bitumen comes in two main types: SBS (Styrene-Butadiene-Styrene) and APP (Atactic Polypropylene), each with different properties relevant to Myrtle Beach conditions.

SBS vs APP Modified Bitumen: Which Is Better for Coastal SC?

SBS modified bitumen uses a rubber modifier that provides excellent flexibility and elongation, making it better at handling the expansion and contraction cycles that Myrtle Beach temperatures create. SBS can be installed using cold adhesive, hot mopping, or self-adhering sheets — all of which are viable in our climate.

APP modified bitumen uses a plastic modifier and is typically torch-applied (heated with an open flame to bond the material). APP provides better UV resistance and handles high temperatures well, making it suitable for Myrtle Beach summers. However, the torch application process raises fire safety considerations, particularly on occupied commercial buildings.

For most Myrtle Beach applications, SBS is the preferred choice because of its superior flexibility, multiple installation methods, and better performance in humid conditions. The cold-adhesive SBS installation avoids the fire risk of torch application while still delivering excellent performance.

Modified Bitumen Coastal Performance

• Lifespan: 15 to 20 years in coastal conditions
• Wind resistance: Good — multi-layer construction provides redundancy, but not as wind-resistant as fully adhered TPO or PVC
• Salt air resistance: Fair — asphalt-based materials are moderately affected by salt air over time
• Walkability: Excellent — modified bitumen produces a durable, walkable surface that handles foot traffic better than any single-ply membrane
• Puncture resistance: Very good — the multi-layer construction resists punctures from debris and foot traffic
• Heat application note: Torch-applied APP installation during Myrtle Beach summers (90+ degree days) requires careful scheduling and safety protocols. Self-adhering or cold-adhesive SBS avoids this issue entirely

Pros and Cons for Myrtle Beach

Best For

Modified bitumen is the best choice for flat roofs that need regular foot traffic — rooftop HVAC access areas, rooftop decks, restaurant rooftops with equipment, and commercial buildings with frequent maintenance access. It is also a solid choice when overlaying an existing modified bitumen roof to extend service life without a full tear-off.

Built-up roofing (BUR) is the oldest flat roofing technology still in active use. Also known as "tar and gravel" roofing, BUR consists of alternating layers of bitumen (asphalt or coal tar) and reinforcing fabric (fiberglass or organic felts), topped with a surface layer of gravel, mineral granules, or a reflective coating. BUR has protected commercial flat roofs for over 100 years, and when properly installed, it remains a viable option — with important caveats for Myrtle Beach.

How BUR Works

A typical BUR system consists of 3 to 5 alternating layers of bitumen and reinforcing plies. The multiple layers create redundancy — even if one layer is compromised, the layers beneath continue to protect. The top surface is typically either loose gravel (aggregate), mineral cap sheets, or a reflective coating. The number of plies determines the system's classification: a 3-ply BUR, 4-ply BUR, etc.

Critical Hurricane Zone Warning: No Gravel Ballast

BUR Coastal Performance

• Lifespan: 20 to 30 years depending on number of plies and maintenance
• Wind resistance: Fair to good — the weight of BUR provides some wind resistance, but it is not designed for the high uplift forces in hurricane zones. Mineral cap sheet versions perform better than smooth-surfaced systems
• Salt air resistance: Fair — asphalt-based bitumen is moderately affected by salt air, and exposed surfaces can degrade faster than membrane roofs
• Waterproofing: Excellent — the multiple layers provide outstanding waterproofing redundancy. BUR's greatest strength is its ability to resist leaks even when individual layers are compromised
• Weight: Heavy — BUR is the heaviest flat roof system. The building structure must be designed to support the additional load, which can add cost to new construction or limit its use on existing buildings

When BUR Makes Sense in Myrtle Beach

BUR is most appropriate for large commercial flat roofs where the building structure can support the weight, where maximum waterproofing redundancy is desired, and where a reflective cap sheet (not gravel) surface is used. It is commonly found on older commercial buildings in the Myrtle Beach area, and re-roofing with a new BUR system over an existing one can be cost-effective when the structure supports the added weight.

Pros and Cons for Myrtle Beach

Best For

BUR is best suited for large commercial and industrial flat roofs with adequate structural capacity, buildings where maximum waterproofing redundancy is the top priority, and re-roofing projects over existing BUR where the structure can handle additional layers. For new construction in Myrtle Beach, single-ply membranes (TPO or PVC) have largely replaced BUR due to lower weight, faster installation, better wind performance, and competitive pricing. For a broader look at commercial options, see our commercial roofing guide for coastal Myrtle Beach.

The following comparison tables rate every major flat roof material across the performance factors that matter most in Myrtle Beach. Use these to narrow down your options before consulting with a contractor.

Table 1: Material Specifications Comparison

*EPDM coastal lifespan reduced from 25-30 year manufacturer rating due to salt air, humidity, and adhesive seam degradation. Data reflects real-world performance in coastal SC.

Table 2: Coastal Suitability Ratings by Environmental Factor

This table rates each material specifically for the environmental conditions found in Myrtle Beach and along the Grand Strand. Ratings are on an A+ to C scale based on material performance data and our direct experience installing and maintaining these systems in coastal South Carolina.

With all the material data in hand, how do you actually decide? The right flat roof material depends on your specific property, location, budget, and priorities. Here is a decision framework that accounts for the factors that matter most in coastal South Carolina.

Step 1: Residential vs Commercial

Residential flat roofs (home additions, sunrooms, carports, modern flat-roof homes) are typically smaller in area and have lower traffic requirements. TPO and EPDM are the most common residential choices, with PVC for oceanfront homes. Modified bitumen works well for small walkable sections like rooftop decks.

Commercial flat roofs (hotels, retail, offices, restaurants, warehouses) involve larger areas, more rooftop equipment, and stricter code requirements. TPO dominates the commercial market for good reason — it offers the best combination of cost efficiency at scale, energy savings, and hurricane code compliance. PVC is standard for restaurants and food-service buildings. For more on commercial applications, see our commercial roofing coastal guide.

Step 2: Distance from the Ocean

Salt air concentration decreases with distance from the coast, and this should influence your material selection:

• 0 to 2 miles from ocean (Ocean Boulevard, oceanfront condos, beachfront commercial): PVC or aluminum standing seam metal. Salt air at its most aggressive. Material must have top-tier salt resistance.
• 2 to 5 miles from ocean (central Myrtle Beach, most of the Grand Strand commercial corridor): TPO is the sweet spot. Good salt resistance at a better value than PVC.
• 5+ miles from ocean (Conway, inland areas of Carolina Forest): All materials are viable including EPDM. Salt air concentration is low enough that it is no longer the primary material driver.

Step 3: Wind Zone and Building Code Requirements

Horry County has specific wind design speed requirements based on your property's location. Your roofing contractor should verify your exact wind zone classification and select a material and attachment method that meets code. Generally:

• 130+ mph zones: Fully adhered TPO, PVC, or standing seam metal. No ballasted systems. Enhanced edge metal per ANSI/SPRI ES-1.
• All coastal areas: Gravel-topped BUR is prohibited. Cap sheet or coated surfaces only for BUR.
• Secondary drainage required: Overflow scuppers or secondary drains are required by code to prevent catastrophic ponding if primary drains fail.

Step 4: Budget Considerations

Flat roof material costs vary significantly. Rather than looking only at upfront cost, consider the total cost of ownership over the roof's lifespan — including energy savings, maintenance costs, and expected service life. A material that costs more upfront but lasts 10 years longer and saves on energy costs may actually be the most affordable choice over the long term. Contact WeatherShield at (843) 877-5539 for a detailed estimate tailored to your property.

Step 5: Building Use and Special Requirements

• Restaurant or commercial kitchen: PVC (grease and chemical resistance is essential)
• Rooftop HVAC or frequent maintenance access: Modified bitumen (walkable surface)
• Warehouse or industrial: TPO or EPDM (large area, cost-driven)
• Hotel or resort: TPO or PVC (energy efficiency and appearance)
• Residential addition or sunroom: TPO for value, PVC for premium

Step 6: Ventilation Matters

Regardless of which material you choose, proper flat roof ventilation is critical in Myrtle Beach's humid climate. Trapped moisture beneath the roof membrane accelerates substrate deterioration, promotes mold growth, and can cause premature membrane failure. Read our flat roof ventilation guide for detailed information on ventilation strategies for each material type.

Step 7: Get a Professional Assessment

The best material decision starts with a professional assessment of your specific property. Factors like existing roof structure, load-bearing capacity, drainage design, equipment placement, and local wind zone classification all influence which material is optimal. WeatherShield Roofing provides free flat roof assessments that include material recommendations, drainage evaluation, and code compliance review for your specific property. Call (843) 877-5539 or visit our flat roof systems page to learn more about our flat roof services.