· by Michael Blair, Nashville's Countertops
Wood is one of the few countertop materials that can be sanded and refinished where it sits, and water left standing on it does real damage. Both shape how you live with it. If you are still weighing wood against stone and quartz, our post on matching a worktop to how you cook sets them side by side.
Oil or film finish
Food-grade mineral oil and paraffin wax soak into the wood rather than sitting on top of it. The USDA Forest Products Laboratory’s Wood Handbook says mineral oil penetrates without ever curing and still improves water resistance, that paraffin oil and wax do not go rancid or support microbes, and that buyers should look for products labeled food grade. The same chapter steers people away from olive, corn and other vegetable oils, which can turn rancid and feed mildew and bacteria, so the bottle by the stove is not the one to use. An oiled top is kept up by oiling it often: Grothouse’s use and care guide, from a maker of wood countertops, gives a rule of thumb of once a week for the first month and at least monthly after that, adjusted for the room and how hard the top is worked.
A film finish such as polyurethane or varnish sits on the surface instead. The Wood Handbook rates film finishes generally the easiest to clean and more resistant to staining than oils or sealers, with the catch that the film may eventually crack, chip and peel. An oiled top asks for more frequent attention; a film asks for less until it fails, and then it needs refinishing.
What ruins a wood countertop?
Standing water is what ruins a wood top, whether it collects at the sink, under a dish rack or around the base of a kettle. Grothouse’s care guide says liquid left on the block can stain it and make the wood swell, and that the swelling can end in failed glue joints and warping. The Wood Handbook makes a similar point about finishes: the less water reaches them, the longer they last.
The sink cutout needs the most protection. Grothouse’s installation guide says any new cut in the top should be sealed with oil, and that edges exposed to constant moisture, an undermount sink cutout being its example, need a permanent sealer such as polyurethane or clear acrylic caulk. It also calls for a moisture barrier or sheet metal cover over a dishwasher or warming drawer, to keep heat and steam off the underside of the wood. Which way the sink itself should mount is a separate decision, covered in our post on undermount and drop-in sinks.
- Oil finish: easy to renew, reapplied often
- Film finish: easier to clean, can eventually crack and peel
- Never let water stand, especially at the sink
- Seal every cut edge, and the sink cutout with a permanent sealer
- Fasten the top so it is free to move
Movement in our humidity
Wood swells as it takes on moisture and shrinks as it dries. According to the Wood Handbook it moves most in the direction of the growth rings, about half as much across them and only slightly along the grain, which is why a wide top changes in width far more than in length. Indoors, the house sets the conditions more than the Middle Tennessee weather does: the handbook puts air-conditioned rooms at around 45 to 55 percent relative humidity and notes that winter heating lowers indoor humidity. With normal changes in humidity, dry wood moves only a little, but a top that is pinned in place has to relieve that movement somewhere.
Grothouse’s installation guide says to drill holes 3/8 inch larger than the screw in the cabinets or mounting brackets and to fit the screws with large washers, so the top can move on them, and it warns that a top screwed down without that room can crack and split. The handbook adds that wood should be brought to the moisture content it will have in service before it goes in, to head off cracks of the kind it describes in furniture.
Can a wood countertop be repaired?
Knife marks and wear come out. Grothouse’s care guide tells owners to use a steel scraper or sandpaper as needed to keep an oiled top smooth and free of deep cuts, then oil it again. A chip in stone is a repair job for a fabricator, as our post on chipped and cracked stone explains, while a worn oiled wood top can be scraped and re-oiled at home.
That makes wood a reasonable choice for a household that cooks a lot, provided the sink area is sealed properly and nobody leaves water sitting on it. If you are deciding between wood and granite or other natural stone for part of the kitchen, or want to talk through where the sink should go, ask us for a free estimate.
Sources
- USDA Forest Products Laboratory, Wood Handbook: Wood as an Engineering Material (FPL-GTR-282, 2021) — Mineral oil penetrates without curing; paraffin and wax food safe; avoid vegetable oils; film finishes easier to clean and more stain resistant but may crack, chip and peel; less water exposure prolongs finish life; directional shrinkage; indoor humidity set by heating and air conditioning; install at in-service moisture content; warping, checking and splitting
- Grothouse, Countertop Use & Care — Oil once a week for the first month, then at least monthly; dry looks mean oil, sticky means too much; standing liquid stains, swells, causes glue-joint failure and warping; scrape or sand out deep cuts and re-oil
- Grothouse, Countertop Installation Guide — Holes 3/8 in oversize with large washers so the top can move; screwing it down tight risks cracking and splitting; seal cut edges, permanent sealer at undermount sink edges; moisture barrier over dishwasher and warming drawer compartments
FAQ
Living With a Wood Countertop in a Kitchen — questions
Can I put a sink in a butcher block worktop?
Yes, with more care than the rest of the top needs. Every cut edge should be sealed, and Grothouse’s installation guide calls for a permanent sealer such as polyurethane or clear acrylic caulk on edges that see constant moisture, such as an undermount sink cutout. Standing water should be wiped up right away, because it can stain the wood and lead to swelling, failed glue joints and warping.
How often does butcher block need oiling?
For a penetrating mineral oil finish, Grothouse suggests once a week for the first month and then at least monthly, adjusted for the room and how much the top is used. Wood that looks dry is due, and a top that feels slightly sticky has had too much. A film finish needs no routine oiling, but the Wood Handbook notes the film may eventually crack, chip and peel, and then it needs refinishing.
Will a wood worktop crack in Nashville humidity?
It can. Wood swells and shrinks as its moisture content changes, and the Wood Handbook lists warping, checking and splitting among the results. A top screwed down with no room to move is one cause, which is why Grothouse’s guide calls for oversized screw holes and large washers. Standing water and a top installed before it reaches the moisture content it will live at are others. Indoors, the air conditioning and heating set the humidity the top lives in more than the weather does.
Is butcher block a good countertop?
It is for a household that cooks a lot and will look after it. Wood can be scraped, sanded and re-oiled where it sits, which no stone allows, but standing water stains and swells it, so the sink area has to be sealed properly and nobody can leave water sitting on the top.