When a deck fails in the Chicago suburbs, it rarely fails in the summer. It fails in March, after the boards have spent four months getting soaked, frozen solid overnight, and thawed again by afternoon, over and over until something gives. I wanted to understand which materials actually survive that cycle and which ones quietly fall apart, so I called someone who has watched it happen on hundreds of decks.
Radu Oprea owns Wolf Spirit Deck, a deck builder in Naperville and the surrounding Chicago suburbs, and has been building here for more than a decade. He has also been called back to inspect and rebuild plenty of other people’s work, which means he has seen how every common decking material ages once a few hard winters get hold of it. What follows is most of our conversation, lightly edited for length.
First, what is actually happening to a deck in winter here?
I asked Radu to explain the mechanism before we got into materials, because “freeze-thaw” gets thrown around a lot without anyone saying what it does.
“It is water,” he said. “That is the whole story. Wood is full of tiny channels, and it drinks up moisture from snow and rain. When that water freezes, it expands. It pushes the wood fibers apart from the inside. Then it thaws and the wood contracts again. One cycle is nothing. But around here we get that cycle dozens of times every winter, sometimes a few times in a single week in February. Do that for five years and the wood is a different material than the one you installed.”
He said the damage shows up in a predictable order. “First the surface checks, those little hairline cracks along the grain. Then the boards start to cup or warp because they are drying unevenly. Then you get real splits, usually around the fasteners, because that is where water sits. By then the board is not just ugly. It is a splinter hazard and sometimes a structural one.”
Pressure-treated wood: the most common, and the one that suffers most
Most decks in the area are still pressure-treated pine, because it is cheap upfront. I asked Radu how it holds up over five years of real Naperville winters.
“Honestly, it is the material I get called back to look at the most,” he said. “The pressure treatment protects against rot and bugs, which is real, and people think that means it is protected against everything. It is not. The treatment does almost nothing for freeze-thaw. The wood still absorbs water, it still freezes, it still moves.”
He was blunt about the timeline. “A pressure-treated deck that nobody maintains will start showing serious cracking and warping in three to five winters here. If the owner is diligent, sealing it every year or two, cleaning it, keeping water from pooling, you can stretch that out a lot. But that is the catch. Most people do not keep up with it. They seal it once when it is new and never again. And an unsealed pressure-treated deck in this climate ages fast.”
His bottom line on wood was not that it is bad, but that the real cost is hidden. “The board is cheap. The maintenance is not, if you actually do it. And if you do not do it, you are buying another deck in ten years.”
Cedar: prettier, a little tougher, still thirsty
I asked whether cedar, which a lot of homeowners want for the look, does any better.
“Cedar is a nicer wood, no question,” Radu said. “It has natural oils that resist rot better than treated pine, and it looks beautiful for the first few years. But it is still wood, and it still absorbs water, so the freeze-thaw cycle still gets it. Cedar is a middle ground. It ages better than pressure-treated, but it is needy. It wants to be sealed and maintained even more than people expect, because once it dries out and goes gray and starts cracking, there is no easy fix. You are sanding and refinishing, or you are living with it.”
He said cedar makes sense for a specific kind of owner. “If you love the look and you are genuinely willing to maintain it, cedar can be great. If you are buying it because you think it is low-maintenance, you are going to be disappointed by year four.”
Composite and PVC: where the freeze-thaw problem mostly goes away
This was the part I most wanted his honest read on, because every composite manufacturer claims their product is bulletproof. I asked what he actually sees after five years.
“Composite is where the freeze-thaw problem mostly stops being a problem,” he said, “and the reason is simple. The good boards have a polymer cap, a plastic shell sealed around the core. Water cannot soak in. If water cannot get into the material, freezing cannot tear it apart. That is the entire mechanism, and the cap shuts it down.”
But he was careful not to oversell it. “Not all composite is equal, and this is where people get burned. Some cheaper boards are only capped on the top surface. The sides and the bottom are exposed. So water gets in from underneath, where you cannot see it, and you get swelling and soft spots down the road. I push people toward boards capped on all four sides for exactly this climate. It costs a little more and it is worth every dollar here.”
I asked about the one knock on composite, that it expands and contracts in temperature swings. “It does move a little with heat and cold,” he admitted. “That is real. But it moves as a sealed unit, it does not crack from water expanding inside it, because there is no water inside it. The installer just has to account for that movement with proper gapping and fastening. Done right, a capped composite deck I built five years ago looks almost the same today as the day we finished it. That is not something I can say about pressure-treated.”
He mentioned PVC as the extreme end. “Full PVC, all plastic, no wood fiber at all, is the most water-resistant thing you can put down. For someone who wants maximum freeze-thaw resistance and does not care about the higher price, it is the top of the line. For most people, a good capped composite gets them ninety percent of the way there for less money.”
What he tells homeowners who are deciding right now
I closed by asking Radu what advice he gives a Naperville homeowner standing in the driveway trying to choose.
“I tell them to be honest with themselves about maintenance,” he said. “If you are the kind of person who will seal a wood deck every single year without fail, wood can work and it will save you money upfront. If you are not, and most people are not, then you should look hard at capped composite, because this climate is brutal on anything that drinks water. I would rather talk someone into the right material once than rebuild their deck in eight years.”
He added one last thing that stuck with me. “People focus on the price of the boards. They should be thinking about the cost over fifteen winters. That is the number that actually matters around here.”
Radu Oprea is the owner of Wolf Spirit Deck. The observations in this article are drawn from his field experience and reflect his views.