Tom's Mulch Fence & Deck has published guidance on the industry standard that governs how composite and PVC deck boards are rated, ahead of the autumn freeze-thaw season across southwest Ohio. The company is directing property owners toward performance data that is publicly available but rarely reviewed during material selection.
Composite and plastic lumber deck boards sold in North America are rated under ASTM D7032, a specification maintained by ASTM International that establishes performance ratings for deck boards, stair treads, guards and handrails. The standard sets out the test methods a product must pass before it can be recognized under model building codes, and it applies across the category rather than to any single manufacturer.
Those methods include flexural testing, temperature and moisture effects, ultraviolet resistance, freeze-thaw resistance, biodeterioration and fire performance. Deck boards are additionally evaluated for creep-recovery, allowable load, mechanical fastener holding and slip resistance. Three of those categories, ultraviolet resistance, freeze-thaw resistance and moisture effects, correspond directly to the conditions decks encounter in the region.
"Homeowners are shown color samples and a warranty document, and that is usually where the conversation ends," said Judd Powell, Owner of Tom's Mulch Fence & Deck. "The testing data exists, it is public, and almost nobody looks at it."
The standard itself notes that composites should not be assumed to behave like wood. It states that structural, physical and fire attributes may differ because of the presence, type and quantity of plastic in the composite, and it includes specific provisions addressing sensitivity to temperature, ultraviolet exposure and freeze-thaw cycling.
That distinction matters at the point of installation. Framing layouts, fastening methods and spacing practices developed for lumber do not transfer automatically to composite products, which is why the standard evaluates fastener holding and thermal behavior as separate categories rather than assuming performance carries over from wood.
Individual product results are published in evaluation reports issued by ICC Evaluation Service, which are searchable and free to read. Those reports identify the manufacturer, the product line and the span rating assigned, allowing a property owner to look up the specific boards named in a quote rather than relying on general category descriptions or marketing material.
Span rating is the figure most directly tied to construction. It indicates the maximum distance a board may span between supports for a given end use, which in turn determines joist spacing beneath the surface. Boards carrying different span ratings require different framing layouts, which is why the rating functions as a structural specification rather than a product feature.
The distinction becomes practical when a homeowner changes material after framing has been planned. A board with a shorter span rating than the one a deck was designed around requires closer joist spacing, and that is a framing decision rather than a surface one. Reviewing the rating before framing begins avoids revisiting the structure later.
Slip resistance and biodeterioration are the categories most often overlooked. Slip resistance affects surfaces near pools or in areas that stay damp, while biodeterioration testing addresses the biological growth that develops on decking held in prolonged shade or moisture. Neither is visible in a showroom sample, and both describe conditions common on north-facing decks and those under heavy tree cover.
Powell said the ratings matter most where site conditions are demanding. "A deck in full sun and a deck under heavy tree cover are not facing the same problem. The test categories are already separated that way. It is worth knowing which one a board is strong in."
The standard covers a range of formulations, including polyvinyl chloride boards, polyethylene-based composites containing wood fiber, and polypropylene blends, in both solid and hollow cross-sections. Products within that range vary considerably in density and moisture absorption, which is why each formulation is tested according to its own composition and intended structural application rather than against a single category benchmark.
Property owners can review the test categories through the ASTM D7032 listing on the ASTM International website and search product-specific results through the ICC Evaluation Service directory. Tom's Mulch Fence & Deck builds decks in wood, composite and PVC, along with fences, gates, porches and outdoor structures for residential and commercial properties across the Miami Valley region of Ohio.
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For more information about Toms Mulch Fence and Deck, contact the company here:
Toms Mulch Fence and Deck
Corey Hughes
+19377076878
cjhughes3139@gmail.com
2107 Ferry Rd, Sugarcreek Township, OH 45305, United States
