Solid wood furniture is built from boards of real wood, and those boards trade moisture with the air for as long as the piece lasts. Damp air makes wood swell, and dry air makes it shrink. Held at a steady, moderate humidity, a dresser moves very little.
I'm Michael Ruhr, and I work the floor at Merit Home Furniture in Duncan. On Vancouver Island, the trouble comes from particular rooms, like a bedroom full of wood furniture on a cold outside wall in a wet November, or the space beside a woodstove in January.
In more than four years at Merit, I haven't seen or heard of a humidity problem with wood furniture. Merit sells a lot of solid wood, too. Mildew here shows up on houses and roofs, so this guide is about the few rooms where wood has a hard time.
What is the ideal humidity for wood furniture?
The ideal humidity for wood furniture is 30 to 50 percent, held as steady as the house allows. That is Health Canada's range for homes, from its current guide to moisture and mould. Its 2016 factsheet narrows winter to 30 to 35 percent, since a house in very cold weather may not hold more than 30 without condensation on the windows. At the damp end, the Canadian Conservation Institute, which advises Canada's museums, draws its line at 75 percent.
Is 50% humidity in a room too high?
Fifty percent humidity is fine for wood, but it is the level above which Health Canada's guide says to run a dehumidifier.
Is 10% moisture in wood bad?
Ten percent moisture in wood is normal indoors. The US Forest Products Laboratory's Wood Handbook recommends 6 to 10 percent for individual pieces of furniture in most of the United States, averaging 8. For damp, warm coastal areas it gives 8 to 13, averaging 11. It has no figure for a cool, damp coast, but a heated Island house in January puts wood near 6.5 percent.
Humidity levels for wood furniture, and what to do at each
Each humidity level below comes with the moisture wood settles at in a room held at 21°C, from the Wood Handbook's equilibrium table.
| Room humidity | Effect and fix |
|---|---|
| Under 30%, wood under 6.2% | Wood shrinks, and tight joints and film finishes can crack, most often right beside a woodstove or baseboard heater. Move the piece out of the heat, and add moisture only while the windows stay dry. |
| 30 to 50%, wood at 6.2 to 9.2% | Within the Handbook's range for furniture: a heated, lived-in Island room most of the year. |
| 50 to 65%, wood at 9.2 to 12.0% | Wood swells and snug drawers can stick, in cool bedrooms, basements and a wet fall. A dehumidifier in that room fixes it. |
| 65 to 75%, wood at 12.0 to 14.4% | Leather or dirty fabric can grow mould if it lasts. Heat and air out the room. |
| Over 75%, wood over 14.4% | Damp by the Conservation Institute's line, and past 80 to 85 percent mould becomes likely even on clean wood. Find where the water comes from. |
A hygrometer (a humidity gauge) tells you which row a room is in. Health Canada's factsheet says any hardware store sells one, while the Conservation Institute calls cheap ones unreliable and puts an accurate instrument at $100 or more. I'd treat a cheap reading as a rough guide.
What Vancouver Island's wet winters and dry summers do to indoor humidity
Vancouver Island is wet in winter and dry in summer. Environment and Climate Change Canada's 1981 to 2010 normals put Nanaimo Airport at 197 mm of precipitation in November and 25 mm in July. North Cowichan, just north of Duncan, gets 194 mm in January. The Alberni Valley is wetter: Robertson Creek, northwest of Port Alberni, averages 2,154 mm a year, 353 mm of it in November.
Heating dries that air indoors. Thirty years of records at Comox Airport put January's vapour pressure, a measure of how much water the air carries, at 0.74 kPa. Saturated air at 20°C is 2.34 kPa by the Conservation Institute's figure, so that air warmed to 20°C reads about 32 percent before cooking and showers add to it.
Why solid wood swells and shrinks with the seasons
Solid wood swells and shrinks across the grain and barely at all along it. The Wood Handbook gives each species a coefficient, the share of its width a board changes per point of moisture. Flat-sawn red oak, with the growth rings running across the board's width, is 0.00369. Quartersawn, with the rings on edge, it is 0.00158.
Take a 6-inch drawer side in flat-sawn red oak. From a room at 30 percent to one at 65, it goes from 6.2 to 12.0 percent moisture and grows 0.13 inch (6 x 0.00369 x 5.8). Quartersawn, it grows 0.055 inch. If drawers like these stick in a wet fall, drying the room frees them; planing them to fit would leave them loose by winter.
Real furniture rarely makes the whole trip: the Conservation Institute says most pieces take many days, even months, to respond fully. A finish only slows it. In the Handbook's pine test, three coats of urethane varnish blocked 90 percent of the moisture after a day and 44 percent after two weeks.
Cracks and finish checking near a woodstove
Solid wood cracks when it shrinks while something holds it, such as a glued joint or a screw through a wide top. The Conservation Institute rates floating panels, which sit loose in a frame, as low sensitivity to humidity swings. Plain furniture with tight joints, and veneer glued over a continuous piece, rate high: a swing of 20 points either side of normal can do small to severe damage.
The Institute adds that order matters. Swelling in damp weather can crush joints invisibly, which makes them likelier to split when the air turns dry: a damp November, then a woodstove January. Finish checking, the fine cracking in a varnished or painted top, is the same movement at work, as a film finish is prone to cracking and loosening.
How far should wood furniture sit from a woodstove or baseboard heater?
No source here gives a humidity-safe distance from a woodstove, so start with fire safety. A certified stove's clearances to anything that burns are in its installation instructions, and furniture burns. Past that, farther is kinder to wood, since a radiant stove warms whatever faces it, as CMHC's wood-heating guide notes. The Conservation Institute advises keeping wood furniture away from fireplaces and baseboard heaters.
For a stove room under 30 percent, CMHC's guide describes the kettle of water many wood-heating households use, set on a trivet so the stove top doesn't rust. Leather near a woodstove wants conditioning at least twice a year where its maker's care terms allow it, and the rest of the leather routine has its own guide.
Why is my wooden furniture going mouldy against the wall?
Wooden furniture goes mouldy when the air around it stays damp long enough, often against a cold outside wall. "Shelving or cabinets placed against exterior walls suffer high RH during cold weather," the Conservation Institute says. A dresser pushed tight to the wall blocks the room's warm air, so the wall behind it runs colder. Room air at 20°C and 50 percent reaches 100 percent, its dew point, near 10°C.
How damp is damp enough depends on the surface. By the Institute's table, clean wood needs 80 to 85 percent before mould is likely at all. Leather and dirty fabric go sooner, in about 100 days at 70 percent in a warm room.
Health Canada's guide says to keep beds, bedding and furniture away from outside walls. The Institute's simplest fix for a cold surface is an air gap of 20 cm or more. For mould already on a piece, the guide lists wood as washable with a cloth and an unscented soap solution, dried completely and quickly, without bleach. Everyday cleaning, well short of mould, has a weekly routine for wood finishes of its own.
If mould comes back after cleaning, the guide's advice is to seek professional assistance. Infants, children, seniors, pregnant people and anyone with asthma should stay away from any clean-up. No dresser, solid or veneered, fixes a wet wall, and Merit can't either.
Cabins and cottages left unheated all winter
An unheated cabin spends the winter at whatever the outdoor air brings, and Nanaimo's January averages 93 percent humidity at 6 a.m. and 82 percent at 3 p.m. In air between the two, say 85 to 90 percent at about 4°C, the Wood Handbook's table puts wood at 18.5 to 21.0 percent moisture. The Handbook warns that lumber stored above 20 percent for long, without drying, can start to decay.
For winter visits, the Institute tells seasonal buildings that warming up slowly doesn't protect furniture; keeping a dry spell short does, and a weekend of stove heat is short.
- Leave a recording hygrometer. The Institute calls instruments that record humidity over time the most useful.
- Keep spare pieces out of the attic. The Institute calls attics, basements and garages poor places to store furniture.
- Keep the firewood in the shed. Health Canada's mould guide says to store firewood in the garage or shed.
- Set the heat by humidity. The Institute's example is a Prince Edward Island storage building whose heaters run on a humidistat: on above 50 percent, off at 50. A dehumidifier only helps in a heated room, since GE says one ordinarily will not operate satisfactorily below 41°F (5°C). Robertson Creek averages 2.0°C in January.
- Check with salt. Table salt on clear tape, left where you suspect damp, turns to droplets at 75 percent after some hours.
What type of furniture is best for high humidity: solid wood or veneer?
Furniture for a damp coastal home depends more on how it is built than on whether it is solid wood or veneer, and Merit lists plenty of both. Solid wood that swells in a wet fall shrinks back as the room dries. For the woods on Mako's own site, the Handbook puts red alder at 0.00256, the pines between 0.00194 and 0.00271, and the maples between 0.00248 and 0.00353. Sugar maple, at the top of that range, moves almost as much as flat-sawn red oak. How alder, pine and maple look beside each other is a matter of mixing wood tones in one room, not of humidity.
Particle-based board fails differently. The Handbook says most panels made from particles, unlike plywood, can swell in thickness for good if they get wet.
Solid wood, like the Mako range
190 of Merit's 210 Mako listings name solid wood as the material, and Mako's bedroom suites have no veneer, no MDF and no particleboard. The Mako Brandon six-drawer dresser in the photos is $1,699. Mako is a Surrey, BC company whose site doesn't say where it builds, and what we know about Mako has its own guide. On a solid piece, look for panels that float in a frame and a finished back.
Veneer over MDF, like the Ashley dressers
All three Ashley dressers Merit lists name MDF or engineered wood in their materials. The Ashley Danabrin, $1,299, is hardwood solids and birch veneer over an MDF substrate. On a veneered piece, check the edges and underside wherever a spill or a damp wall could reach the board. None of the three Ashley dresser pages mentions fully finished drawer interiors, so it's worth asking.
Where a piece is made is a separate question from how it is built, and bedroom furniture made in Canada has a guide of its own. Height and drawer count are in choosing a dresser that fits the room, and everything else on bedroom furniture sits on one page.
Where the humidity and wood numbers come from
- Health Canada, moisture and mould guide and 2016 humidity factsheet, checked September 2026.
- Canadian Conservation Institute, incorrect relative humidity, basic care of wooden furniture and CCI Notes 7/2 on finishes, checked September 2026.
- USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-190), chapters 4, 11, 13 and 16, checked September 2026.
- Environment and Climate Change Canada, 1981 to 2010 normals for Nanaimo A, Comox A, North Cowichan and Alberni Robertson Creek, checked September 2026.
- CMHC, A Guide to Residential Wood Heating (2008), checked September 2026.
- GE Appliances, dehumidifier operating conditions, checked September 2026.
- Mako Wood Furniture, woods and Surrey office, checked September 2026.
- Merit's live product and delivery pages, and the owners' answers, checked September 23, 2026.
Comparing solid wood and veneer dressers in Duncan
Solid wood and veneer dressers are easiest to judge side by side. Most of our Mako listings point to the Duncan showroom on Ingram Street, open Monday to Saturday, 9 to 5, so ask which pieces are on the floor before you come. Nobody hovers while you open drawers. If the piece is for a cabin or a woodstove room, tell us.
Delivery from Merit's Duncan store is $150 across the Island, assembly included, and for the Gulf Islands, the store tells you on the phone what it can do. The whole Mako collection carries its prices online, and the Island page covers ferry runs and our four stores.