Is it normal for deck posts to be buried directly in the ground?

The way your contractor handled those posts is definitely the old-school method, and while it was standard practice for decades, it's generally considered a shortcut by modern building standards. By burying the 6x6s directly in the dirt on top of a concrete pad, he created a situation where the wood is constantly exposed to ground moisture. Even with pressure-treated lumber, being encased in soil or sitting in a 'cup' of concrete at the bottom of a hole is the number one cause of premature rot. In a perfect world, he would have poured concrete piers all the way to a few inches above the grass line and used a **Simpson Strong-Tie** stand-off bracket to keep the wood completely dry. Since the deck is already finished, you're looking at a lifespan of maybe 10 to 15 years for those posts instead of 25 plus. It's not going to fall down tomorrow, but you'll want to keep a close eye on the base of the wood where it meets the soil for any signs of softening or 'mushiness' in about a decade. $17,600 is a very competitive price for a full tear-down and composite install, especially with the current cost of materials. Most guys charging that rate are going to move fast and skip the extra labor of forming up above-ground piers. If the finish work and the sliding door transition are as clean as you say, he likely knows his way around a saw but just stuck to his 'fast' framing habits. If you're really worried about it, you can clear some of the dirt away from the post bases and backfill the top few inches with gravel to help with drainage. But honestly, for that price point, you got a decent deal on the aesthetics and the structural skeleton. Just make sure the beam-to-post connections have proper **through-bolts** or heavy-duty structural screws rather than just nails, as that's arguably more important for the immediate safety of an elevated deck than the burial depth.

The longevity of your installation depends almost entirely on whether your contractor sourced UC4B rated timber, which is specifically designated for heavy-duty ground contact, rather than the more ubiquitous UC4A grade that frequently lacks the preservative retention levels required to withstand constant saturation in a subterranean environment lacking a dedicated drainage plane. I’d also check if he applied a copper naphthenate solution to any field cuts, beacuse if he dropped a raw, cut end onto that concrete pad, the internal heartwood—which is notoriously resistant to pressure treatment penetration—will likely begin to compromise the structural integrity far sooner than the exterior sapwood might suggest.

Oh wow, $17k for a full composite setup sounds like an absolute steal! I'm just starting to plan my first DIY build and I'm totally obsessed with the white railing look too. Since you mentioned the light brown boards, do they get super hot in the direct sun? I'm worried about my dogs burning thier paws if I go with a darker tan color!

Since those posts are already buried, you need to seal the wood where it meets the grass line immediately to stop the rot before it starts. I'd grab a few cans of Copper-Green Wood Preservative and soak the base of those 6x6s as much as possable. It’s a copper naphthenate solution that’s way better than the standard stuff for ground contact. Even if the contractor used treated lumber, that extra layer of Copper-Green acts as a chemical barrier against the moisture in the soil. It's the only way I'd trust a buried post to last more than a decade without turning into mush.

Quick update—I checked the tags on the leftover wood and they were actually UC4B rated for ground contact! To be safe, I also applied some Copper-Green around the base as suggested. Feeling way more confident about the deck now. Thanks for the peace of mind, everyone. Now I just need to see if the boards get too hot for the dog!