· by Michael Blair, Nashville's Deck
Composite decking is sold as maintenance free and wood as a constant chore. Neither is quite true. What separates them here is heat underfoot, refinishing, and how each handles our humidity. If you’re already leaning toward composite, our composite decking page covers how we build with it.
What upkeep does each kind of decking need?
Wood needs cleaning and a fresh coat of sealer or stain every few years, and boards that take the full afternoon sun go first. We judge it by the boards rather than the calendar, and the steps we follow are in our post on cleaning and sealing a deck. A gray, rough wood deck can also be sanded back and recoated, which is part of our deck repair and resurfacing work.
Composite needs washing, and Trex’s care and cleaning instructions spell out what that means: a hose, warm soapy water and a soft bristle brush, with oil, grease and food spills cleaned off within seven days to keep the stain warranty. Sanding is where composite parts company with wood. Trex does not recommend it, says it changes the look of the surface, and voids the warranty for any condition sanding causes, so a deep scratch is something you live with or fix by swapping the board.
The older uncapped lines change color on their own, too. Trex’s page on natural weathering says an early-generation deck typically fades to a lighter color 12 to 16 weeks after installation, while its newer boards carry a protective shell against weather and age.
How hot does dark composite decking get?
Dark composite gets hot in a Nashville August, hot enough that you won’t want to stand on it barefoot for long. The 2026 Trex decking installation guide says the darker the color, the hotter the deck will feel, and tells buyers in hotter climates to choose lighter colors or boards with heat-mitigating technology. On its home page, Trex says its SunComfortable boards build up as much as 35°F less heat than its original boards in lab testing, and the fine print still warns they get hot in direct sun on hot days.
Wood is no escape from that. The same guide lists wood decking with concrete, asphalt and beach sand among the surfaces that heat up in the sun. On a fully exposed south or west deck we also look at the windows, because Trex warns that Low-E glass can concentrate sunlight on decking enough to char or discolor the surface, and TimberTech’s decking installation guide warns that the heat build-up from Low-E glass can make its boards sag, warp or discolor.
- Wood: can be sanded and recoated, needs a fresh finish every few years
- Composite: washed with a soft brush, no sanding, dark colors run hot
- Capped composite: a protective shell that Trex says fights weather and age, where its early-generation boards fade
- Either way the frame underneath is usually wood, and it needs protecting from rot
Can composite decking grow mold?
Composite is not immune to what grows on a damp deck under trees. Trex says its early-generation boards are susceptible to mold and mildew when certain environmental conditions exist and should be cleaned regularly with a deck cleaner, and its care page traces mold on any of its boards back to pollen and dirt left sitting on the surface. Its installation guide adds a detail worth knowing before you scrub: use a soft brush on the boards, never a wire one.
We treat airflow under a low deck as part of the build. When the boards sit close to grade, we keep the sides open enough for air to move and leave a way to clear leaves out from underneath, and our post on the space under a deck goes further into keeping it dry.
Cost over the life
What either deck costs installed depends on the board line, the color, the railing and the frame, so we price both side by side on a written estimate instead of putting a twenty-year figure in a blog post. Our deck guide walks through what moves the price in Nashville. Whatever goes on top, the frame underneath is usually wood, and the Trex guide recommends its joist tape on the tops of joists, rim joists and ledger boards to help prevent rot and wood decay.
The real difference is what you spend your time on. If you won’t keep a finish on wood, composite is the easier deck to own, provided somebody still gives it the spring and fall cleaning Trex asks for. When you want both priced for your own yard, ask us for a free written estimate.
Sources
- Trex, 2026 Trex Decking Installation Guide — Darker colors feel hotter; lighter or heat-mitigating colors for hot climates; wood decking among surfaces that get hot; Low-E glass can char or discolor decking; no wire brush; joist tape on wood framing; span chart
- Trex, Care and Cleaning — Hose, warm soapy water and soft bristle brush; food and grease spills cleaned within seven days for the stain warranty; sanding not recommended and voids the warranty; mold feeds on pollen and dirt left on the surface
- Trex, Natural Weathering for Early-Generation Trex Composites — Early-generation boards fade lighter 12 to 16 weeks after installation and are susceptible to mold and mildew; newer lines have a protective shell
- Trex, home page (SunComfortable Technology) — Up to 35°F less heat buildup than original boards in lab testing; still gets hot in direct sun on hot days
- TimberTech (AZEK), Decking Installation & Maintenance Guide: TimberTech Composite and Specialty Decking (REV 09/23) — Extreme Heat Warning: heat build-up from Low-E glass can make its boards melt, sag, warp, discolor and weather faster; all decking gets hot in the sun, darker colors hotter
FAQ
Composite or Wood Decking in Nashville Humidity — questions
Does composite decking get too hot to walk on?
Dark composite in direct Nashville sun can become uncomfortable barefoot, and Trex’s own installation guide says the darker the color, the hotter the deck will feel. Lighter colors help. Trex says its SunComfortable boards build up as much as 35°F less heat than its original boards in lab testing, and it still warns that they get hot in direct sun. If the deck is unshaded and used barefoot, choose the color with that in mind.
How often does a wood deck need staining?
There is no fixed number of years we would promise, since sun, the finish and foot traffic all change it, and a fully exposed deck comes due sooner than a shaded one. We check with a little water on the sunniest boards: if it sits on the surface the finish is still working, and if it soaks in and darkens the wood we plan a cleaning and a fresh coat.
Can composite decking be installed over an old frame?
Sometimes, if the frame is sound and its joist spacing suits the board. Each composite line has a maximum joist spacing, which Trex publishes as a span chart in its installation guide, and a diagonal layout makes each board cross a longer distance between joists. We measure the existing frame against the chart before quoting, and we would rather replace a tired frame than put new boards on one that will not outlast them.
Is composite decking cheaper than wood?
We cannot answer that in general, because the installed price of either depends on the board line, the color, the railing and the frame. So we price both side by side on a written estimate for the actual yard. Over the years, wood adds a fresh finish every few years, while composite still needs its spring and fall cleaning.