What Is the Difference Between Composite and PVC Decking?
Quick Answer: Composite decking is made from a blend of wood fiber and plastic. PVC decking contains no wood at all – it’s cellular PVC through and through. This difference matters in Illinois because wood fiber absorbs moisture, even in a capped composite board. Full PVC is completely impervious to moisture, making it the better choice for pool decks, shaded decks, and applications where moisture is constant. PVC costs more and retains more heat in summer. Both outlast wood dramatically.
The Core Material Difference
Composite decking: Wood fiber (sawdust, wood flour) combined with plastic (polyethylene or polypropylene), formed into boards. Most quality composite boards are “capped” – meaning a protective polymer shell wraps the wood-plastic core. This cap prevents most moisture penetration.
PVC decking: No wood fiber at all. Cellular PVC foam core, typically with an embossed surface texture that mimics wood grain. Azek is the dominant brand in this category.
The practical implication: composite boards can absorb some moisture through cut ends and any imperfections in the cap. PVC cannot – there is no wood to absorb moisture.
How This Plays Out in Illinois
Illinois’s freeze-thaw cycles are the most relevant climate factor for this comparison. When moisture gets into a material and freezes, it expands. In uncapped or lightly capped composite, this cycle can degrade the board over many winters. In fully capped composite, it’s largely mitigated. In full PVC, it’s a non-issue entirely.
For most standard deck applications in the Fox Valley area, quality capped composite performs very well. For pool decks, perpetually shaded decks, or applications where constant moisture contact is the norm, full PVC offers a meaningful advantage.
Heat Retention: PVC’s Trade-Off
PVC retains heat more than composite. In direct Illinois summer sun, Azek boards in dark colors can reach surface temperatures that are notably higher than comparable composite products. This is a real consideration for pool decks and any deck where children or pets walk barefoot.
Lighter colors help significantly. And TimberTech’s composite products have specifically engineered lower heat absorption into their upper product lines.
How hot does decking get in Illinois summers – both composite and PVC compared.
Cost Comparison
Full PVC is generally more expensive than comparable composite. The premium for Azek Landmark over TimberTech PRO Reserve, for instance, is meaningful – both in material cost and total project cost.
However, PVC’s 50-year warranty (on Azek Landmark) makes the lifetime cost comparison more complex. The full cost-worth-it analysis is covered there.
Important Considerations
Installation differences: PVC expands and contracts more dramatically with temperature than composite. Installation in Illinois’s wide temperature range requires careful spacing management. This is not a DIY-friendly material. Framing and installation requirements for PVC are specific and must be followed.
Appearance: At the premium tier, both composite and PVC look convincingly like wood. Multi-tonal grain patterns in both categories are impressive. Some homeowners prefer the consistency of PVC surface; others prefer specific grain patterns available in composite.
The full comparison of composite vs. PVC decking goes into much more detail on all of these factors.
What to Do Next
The right material for your deck depends on your specific application, site, and budget. Call DDT Deck Builders at 630-200-3945 – we install both and will help you choose the right one.
We serve Oswego, Aurora, Montgomery, Yorkville, Plainfield, and Kane and Kendall County.