By Mario Vlichis, owner of Vilchis Hardwood Floors Updated May 2026
The biggest thing people get wrong about hardwood floors in North Carolina is treating them like furniture. They aren’t. They’re alive. They move with the seasons, the way trees do, just slower and quieter. Once you understand that, taking care of them gets a lot easier.
I’ve been installing and refinishing hardwood in Durham, Raleigh, Cary, Chapel Hill, and Carrboro for over 16 years. The single most common reason a homeowner calls me back about their floors isn’t damage or wear. It’s seasonal movement they didn’t expect. Gaps that opened up in February. Cupping that showed up in August. A board near the door that suddenly sticks up an eighth of an inch.
None of that means anything is wrong with the floor. It usually means the air inside the house got away from you.
So this is a season-by-season guide, written from the perspective of someone who has been called out to fix the avoidable problems.
Why Triangle weather is hard on hardwood
Durham and the rest of the Triangle have one of the more challenging climates in the country for wood floors. The reason is the spread.
In August, outdoor humidity around here regularly sits above 90%. By January, with your heat running, indoor humidity in the same house can fall below 25%. That’s a swing of 65 percentage points across the year, indoors. The National Wood Flooring Association recommends keeping indoor relative humidity between 30 and 50 percent year-round (their full maintenance guidelines are worth bookmarking). Most Triangle homes blow through the top of that range every summer and the bottom every winter, unless you’re actively managing it.
Wood reacts to that. A 5-inch plainsawn red oak board can change roughly 0.09 inches in width when the humidity swings from 30% to 60%. Multiply that across a room full of boards and you get visible gaps in winter and tight, sometimes cupped boards in summer. This is normal. It only becomes a problem when the swing is bigger than the floor was designed to handle, or when it stays at an extreme for too long.
The other factor unique to Durham, especially in older neighborhoods like Trinity Park, Watts-Hillandale, and Forest Hills, is the crawlspace. A study out of Advanced Energy in Raleigh found that traditional vented crawlspaces here stayed above 70% relative humidity all summer, while sealed, conditioned crawlspaces stayed below 60%. Whatever is going on under your floor is going on inside your floor too, just delayed by a few weeks.
So: keep the air in the right range, keep the crawlspace dry, and most of the rest is just routine cleaning.
Spring (March through May)
Spring in the Triangle is a transition period and your floors will tell you about it. The boards that contracted all winter start expanding again as outdoor humidity climbs. Winter gaps close up. Doors that swung freely in February might start to drag a little.
This is the season to check the floors over and address anything that needs attention before summer humidity arrives.
The thing I’d watch for first is gaps that haven’t closed. If you have gaps wider than the thickness of a credit card and they’re still there by late May, that’s worth a call. Persistent gaps usually mean the floor was installed too dry, or there’s an ongoing moisture issue you haven’t found yet.
Switch your humidifier off and your dehumidifier on once outdoor highs are consistently in the 70s. In the Triangle, that usually happens by mid-April. Don’t wait until you feel sticky in the house. The wood feels it before you do.
Get a hygrometer if you don’t have one. They’re $15 at any hardware store. Put one in the main living area and one near any floor that’s been a problem in the past. If you don’t measure indoor humidity, you’re guessing.
Spring is also a good time for a deeper clean. Sweep or vacuum (soft-brush attachment, never a beater bar), then go over the floor with a barely damp microfiber mop and a pH-neutral hardwood cleaner. Bona’s standard cleaner is fine. So is the Rubio Monocoat soap if you have an oiled finish. Skip anything with vinegar, ammonia, or oil soap. Vinegar is acidic and will dull a polyurethane finish over time. Oil soap leaves a residue that builds up and makes recoating later a nightmare.
Summer (June through September)
This is the hard season. Outdoor humidity in Durham routinely hits 90%, peaks above that in August, and stays elevated for weeks at a stretch. The single most important thing you can do for your floors in summer is run your air conditioning consistently.
Central AC dehumidifies as a side effect of cooling. In a well-sized, well-running AC system, summer floor management mostly takes care of itself. But there are a few ways it goes wrong.
The biggest one is people turning the AC off when they go on vacation to save money. Don’t. Set it to 78°F and let it cycle. The “greenhouse effect” of a sealed house in a Triangle summer will cup hardwood floors faster than almost anything else. I’ve seen it happen in a week.
The second is undersized AC. If your system never quite catches up on the muggiest August days, indoor RH stays above 60% and the floors notice. You’ll need a supplemental dehumidifier in the worst rooms.
The third is a vented crawlspace. If the floor cups every summer in the same spot, the problem is almost certainly under the house, not in it. Crawlspace encapsulation runs $5,000–$15,000 for most Triangle homes, which is real money, but for older homes with persistent moisture issues it pays for itself in floor longevity alone.
Summer is also when boards are at their widest, so the seams are tight. That makes it a fine time to mop. Just go light on the water. A microfiber pad that’s been sprayed and wrung out, not a wet mop. Standing water on hardwood is bad in any season but particularly bad when the wood is already at its swollen maximum.
If you have a kitchen or bathroom on hardwood, watch the dishwasher and ice maker lines closely. The most common catastrophic floor damage I see all summer is a slow leak under an appliance that nobody noticed for three weeks. Pull the dishwasher out once a year and look behind it. And in second-floor laundry rooms, if you have hardwood up there, put a water alarm under the washer. They’re $20 and they save floors.
Fall (October and November)
Autumn in the Triangle is the most stable period of the year for hardwood. Outdoor humidity moderates, temperatures drop into a comfortable range, and indoor conditions tend to sit right in the NWFA’s recommended zone without much effort.
This is actually the best time of year to install hardwood in North Carolina, for exactly that reason. The wood acclimates quickly, conditions stay stable during the install, and the floor settles into normal seasonal movement instead of a dramatic swing in either direction. We talk about that in more detail in our post on how long new hardwood should acclimate in a Triangle home if you’re considering it.
For existing floors, fall is mostly about getting ready for winter.
Switch the dehumidifier off once outdoor highs are consistently in the 60s. In Durham, that’s usually mid-October. Don’t run a dehumidifier in fall and a humidifier in winter at the same time, which I’ve seen people do without realizing it. Pick the right tool for the actual indoor RH reading, not the calendar.
Watch the rapid temperature swings. Fall in NC bounces between 75°F afternoons and 40°F nights for weeks. If you’re heating the house aggressively at night and shutting it off during the day, you’re drying the top layer of the wood while the bottom stays saturated from the crawlspace. That’s the recipe for early gaps and light cupping. Try to hold the indoor temperature steadier.
Add area rugs back at entries before the wet, leafy season. Grit tracked in from outside is the number-one cause of premature finish wear. A breathable cotton or wool rug at every exterior door catches most of it before it gets onto the floor.
Winter (December through February)
Winter is the season where most Triangle homeowners notice problems with their hardwood for the first time. Gaps appear. The whole floor looks drier. Sometimes you’ll hear new creaking sounds at night as the wood contracts.
Almost all of this is normal. Heating systems pull moisture out of indoor air, the wood gives up some of its own moisture in response, and the boards shrink slightly. By late February the indoor RH in an unmanaged Triangle home is often down around 22–28%, well below what the NWFA recommends. Gaps of up to about the thickness of a business card between boards are within the range of normal seasonal behavior. They’ll close in spring.
To minimize the swing, run a humidifier. A whole-house unit mounted to the HVAC is the most effective option. A good one runs $400–$1,200 installed and pays for itself in floor and respiratory health over a few winters. Portable units work too but only treat the room they’re in. Aim for 35–40% indoor RH all winter.
Don’t park furniture or rugs directly over heating vents. That dries the wood underneath that one spot faster than the wood around it, and that’s how you get a single board that cups or crowns when the rest of the floor is fine.
Wipe boots and shoes at the door. Road salt isn’t a major issue in NC the way it is up north, but mud, sand, and gritty water all do damage. A boot tray at every entrance during the wet months is the cheapest floor insurance you can buy.
Be patient about gaps. I get a lot of panicked calls in January from new homeowners who just bought a place with original 1940s oak and are convinced something is failing. In almost every case those gaps will close on their own by April. The only winter gaps that are a real problem are the ones wider than about 1/8 inch, in which case there may be an installation or moisture issue worth investigating.
If the gaps in your old Durham floor are dramatic and don’t close, by the way, that’s often a clue that you’ve got bigger issues than the visible floor. There’s a whole conversation to have about what’s actually going on under there, which we covered separately in our refinishing cost guide for Durham.
Year-round basics that matter more than the seasonal stuff
If you do nothing else from this whole guide, do these:
- Put a hygrometer in the main living area. Target 35–50% RH year-round.
- Sweep or dry-vacuum every few days. Grit is the enemy.
- Damp-mop with a microfiber pad and a pH-neutral wood cleaner, no more than once a week, and only barely damp.
- Felt pads on every chair and table leg. Replace them once a year.
- No steam mops, vinegar, ammonia, oil soap, or “all-purpose” cleaners on hardwood.
- Wipe up spills immediately. Standing water for an hour can leave a stain even on a sealed finish.
- Trim your pets’ nails. Long nails on a 70-pound dog will chew through any finish in a year or two.
The maintenance part really is that simple. The harder part is the air, and that’s where most floor problems in the Triangle start.
When to call someone
A few things genuinely need a professional, not a DIY fix:
- Gaps wider than 1/8 inch that don’t close in spring.
- Cupping that doesn’t flatten back out by November.
- Any buckling, where boards lift off the subfloor entirely.
- Black or dark stains that don’t come up with normal cleaning (often a sign of moisture damage under the finish).
- Worn-through finish in high-traffic paths. A recoat is much cheaper than a full refinish, and there’s a window where that’s still an option.
For everything else, the right humidifier and the right hygrometer will do more for your floors than any product I could sell you.
If you’d like us to come take a look at floors that are giving you trouble, we offer free in-home evaluations across the Triangle. Request a quote or call (919) 794-1116. And if you’re still in the planning stage and considering new floors, you can read more about how we approach hardwood flooring in Durham, NC on our service page.
Mario Vlichis is the owner of Vilchis Hardwood Floors at 237 Obie Dr in Durham. He’s been installing and refinishing floors across the Triangle since 2009.
