When it comes to designing a durable, long-lasting, and aesthetically pleasing outdoor deck, 1.5 inch thick composite decking stands out as one of the most dependable options available. The thickness of decking boards plays a critical role in both the structural integrity and the comfort of outdoor living spaces. While many homeowners and contractors are familiar with standard thicknesses such as 0.9 to 1 inch, the 1.5 inch thick composite decking category caters to more demanding applications where strength, durability, and resilience are paramount.
Table of Contents
In this comprehensive guide, we will walk you through everything you need to know about 1.5 inch thick composite decking—from its core benefits, applications, installation methods, to how it compares with standard thicknesses. If you’re planning a deck for a high-traffic area, a rooftop terrace, or a premium backyard retreat, this guide is for you.
What is 1.5 Inch Thick Composite Decking?
1.5 inch thick composite decking refers to decking boards made from composite materials—typically a blend of wood fibers and plastic polymers—with a thickness of 1.5 inches. This thickness level is notably above the industry standard, which generally ranges from 0.9 inches to 1.1 inches.
These thicker boards are designed for superior load-bearing capacity, resistance to warping, and long-term performance in high-impact environments. They are especially suitable for projects where strength and longevity are non-negotiable.
Why Choose 1.5 Inch Over Standard Thickness?
While thinner boards may suffice for simple residential decks, 1.5 inch thick composite decking opens up possibilities for structurally demanding or design-driven applications. Here’s why this extra thickness matters:
Load-bearing capacity: With more material, the board supports heavier loads and wider spans.
Resistance to warping: Thicker boards are less prone to warping or cupping due to environmental stressors.
Better sound insulation: They absorb more impact noise—useful in multi-level decking or rooftop areas.
Visual depth: The boards offer a more luxurious, substantial look.
Advantages of 1.5 Inch Thick Composite Decking
Let’s explore the key benefits of choosing 1.5 inch thick composite decking for your next outdoor project.
3.1 Strength and Stability
Due to their added thickness, these boards are capable of spanning longer distances between joists without sagging. This reduces the need for closely spaced framing members, potentially saving on structural costs.
3.2 High Resistance to Moisture and UV
Like all quality composite decking, the 1.5-inch variety resists rot, mold, mildew, and UV fading far better than wood.
3.3 Better Impact Resistance
The thicker profile cushions impacts better, which is especially useful for commercial decks, rooftop patios, or areas with heavy furniture or grills.
3.4 Enhanced Appearance
The substantial thickness creates a more premium, architectural finish that mimics the look of exotic hardwood planks.
Common Applications of 1.5 Inch Thick Composite Decking
Because of its durability and structural advantages, 1.5 thick composite decking is ideal for the following scenarios:
| Application Area | Reason for Using 1.5″ Thick Boards |
|---|---|
| Rooftop decks | Extra strength compensates for less structural support below. |
| Commercial walkways | Handles higher foot traffic and occasional equipment loads. |
| Pool surrounds | Water-resistant and structurally sound under wet conditions. |
| Raised or cantilevered decks | Greater thickness minimizes flex and deflection. |
| Coastal/marine areas | Withstands salt air, humidity, and stronger environmental stress. |
Material Composition and Manufacturing Process
Most 1.5 inch thick composite decking boards are made from a carefully engineered blend of 55–70% recycled wood fibers and 30–45% plastic polymers, typically recycled high-density polyethylene (HDPE) or polyvinyl chloride (PVC). This combination leverages the best properties of both materials—wood fibers provide natural aesthetics and rigidity, while plastic polymers enhance moisture resistance and durability. In addition to the core components, manufacturers add special additives such as UV stabilizers, color pigments, coupling agents, and binding agents to improve performance and appearance.
Co-extrusion Technology
One of the most advanced manufacturing processes used for high-end 1.5 inch thick composite decking is co-extrusion. This technique involves extruding a durable outer shell layer, often polymer-based, simultaneously with the core material. The shell acts as a protective barrier that significantly enhances the board’s resistance to stains, fading, scratches, and surface wear.
The benefits of co-extrusion include:
Superior stain resistance: The outer shell repels common outdoor contaminants such as food, oils, and dirt, making cleaning easier and maintaining appearance longer.
Improved UV protection: The polymer cap absorbs and disperses harmful ultraviolet rays, preventing discoloration and brittleness caused by prolonged sun exposure.
Increased surface hardness: The tough outer layer resists dents, abrasion, and impacts, which is especially important for thicker boards that are often used in high-traffic or commercial settings.
Moreover, the co-extrusion process allows manufacturers to create a variety of textures and finishes—ranging from wood grain embossing to smooth surfaces—while maintaining consistent quality across each board. This makes 1.5 thick composite decking not only highly functional but also aesthetically versatile for different design preferences.
Comparison Table: 1.5" vs Standard Composite Decking
| Feature | Standard Composite Decking (1.0″) | 1.5 Inch Thick Composite Decking |
|---|---|---|
| Load capacity | Moderate — suitable for typical residential use and light foot traffic. | High — ideal for heavy loads, wider spans, and commercial applications. |
| Visual appeal | Basic to moderate — standard thickness with common design options. | Premium and robust — thicker profile offers a more substantial, luxurious look. |
| Joist spacing requirement | 12–16 inches — requires closer joist spacing to prevent sagging. | 16–24 inches — allows for wider joist spacing, reducing structural costs. |
| Cost per sq. ft. | Lower — more affordable option for standard projects. | Higher — reflects better material quality and enhanced performance. |
| Application suitability | Residential, low-traffic areas like backyard decks or patios. | Commercial, high-traffic, specialty projects such as rooftop decks, pool surrounds, or public walkways. |
Installation Best Practices
Installing 1.5 inch thick composite decking requires attention to a few key details to ensure performance and longevity:
Joist Spacing
Thicker boards allow for increased joist spacing—up to 24 inches on center in some designs—but always refer to the manufacturer’s guidelines.
Fastening Methods
Use hidden clip systems or stainless steel screws designed specifically for composite materials. Pre-drilling may be required in colder climates or on mitered ends.
Expansion Gaps
Leave sufficient space between boards to accommodate expansion and contraction—especially in climates with extreme temperature swings.
Maintenance and Care Tips
Though composite decking is much lower maintenance than traditional wood, thicker boards still benefit from regular upkeep to maintain their appearance and longevity:
Cleaning: Wash seasonally with warm water and mild soap or a specialized composite deck cleaner to remove dirt, grime, and mildew buildup. Using a soft brush can help clean textured surfaces effectively without damaging the board.
Avoid harsh chemicals: Especially those containing chlorine or bleach, as these can degrade the protective polymer cap, causing discoloration or surface damage over time.
Prevent debris buildup: Use a leaf blower, broom, or soft-bristled brush to keep dirt, leaves, and organic matter out of board gaps, which can trap moisture and promote mold growth if left unchecked.
Inspect regularly: Check for any loose fasteners, gaps, or surface wear periodically, especially in high-traffic areas, to address minor issues before they develop into costly repairs.
By following these simple care tips, your 1.5 inch thick composite decking will stay beautiful and durable for many years.
Cost Considerations
The price of 1.5 inch thick composite decking is generally higher than standard composite boards due to the increased amount of raw materials, enhanced manufacturing processes, and superior performance characteristics. While the upfront cost may seem significant, the overall return on investment (ROI) can be substantial. This is primarily because thicker composite decking often requires less frequent repairs or replacements, saving both time and money over the deck’s lifespan.
Additionally, because 1.5 thick composite decking can span greater distances between joists, you may reduce the amount of structural framing required, potentially lowering your initial installation costs. The thicker boards also provide better resistance to sagging, warping, and surface damage, which means fewer maintenance expenses and longer intervals between cleaning or refinishing compared to wood or thinner composites.
Moreover, the enhanced durability and aesthetic appeal of 1.5-inch boards can increase the property’s value, making it a wise investment for homeowners planning to sell or lease. When comparing costs, it is essential to consider these long-term benefits rather than focusing solely on the initial purchase price.
Average Price Range:
| Type of Board | Estimated Cost (per linear foot) |
|---|---|
| Standard composite (1.0″) | $3.00 – $6.00 |
| 1.5 inch thick composite decking | $7.50 – $11.00 |
Note: Prices vary based on brand, finish, and location.
Where to Buy and What to Look For
Many reputable composite decking brands offer 1.5 inch thick options, though availability may be more limited compared to standard profiles. Always check:
Warranty: Look for warranties of at least 25 years, especially for fade and stain resistance.
Certifications: FSC or LEED compliance can indicate sustainable sourcing.
Finish options: Some brands offer multi-tone colors and embossed wood grain textures.
Slip resistance: Especially important for pool areas and wet climates.
Final Thoughts
1.5 inch thick composite decking is not just a premium choice—it’s a performance upgrade for serious outdoor projects. Whether you’re crafting a luxury deck by the sea, designing a commercial terrace, or simply want something that will outlast traditional options, these thick-profile boards are an ideal solution.
While the upfront cost may be higher, the reduced need for frequent maintenance, extended warranty periods, and superior durability make it a smart investment in the long term. If your deck is meant to last, look great, and support real-world usage scenarios, upgrading to 1.5 inch thick composite decking might be the best decision you make.
FAQs
Q: Can I mix 1.5 inch and standard composite decking boards?
A: Technically yes, but visually and structurally it’s not recommended. The difference in thickness can cause uneven surfaces and load inconsistencies.
Q: Is 1.5 inch decking suitable for DIY installations?
A: Yes, especially with pre-grooved hidden fastener systems. However, because of its weight and density, it’s easier with two people and the right tools.
Q: Does it come in grooved and square-edge versions?
A: Most manufacturers offer both, to accommodate different fastening systems and border trim requirements.
