A discussion about wood countertops is not complete without talking about corners. Wood is a natural substance. As such, it absorbs and releases moisture depending on the season regardless of how it is finished. This causes the wood to expand and contract. It’s much like a spaghetti noodle. You toss it in water, it puffs up. You leave that same noodle on the counter to dry, and it shrinks down again. Interestingly, wood expands in width, but not in length. On average, wood changes about 1/16 of an inch per foot in width over a season. On a 25inch top, that’s almost 1/8 of an inch; that’s borderline trouble. If we have a 4ft wide countertop or table, that’s 1/4 of an inch; that’s significant.
So what does this mean for a countertop corners? Well, for corners it is important because the wood doesn’t have an ability to move very well in a traditional miter-joint corner. Overtime, the corner is may crack – perhaps just little, perhaps never, perhaps as big as an 1/8 of an inch. It depends on a lot of factors including wood species, environmental controls in your home, size of top, etc…
Mitered joints are what people normally envision. We can craft glued and epoxied miter-joints, but we’ll raise a red flag that there is a risk of future problems. One of the ways to reduce the risk is to create a loose joint in the corner. Typically, we round the edges a little bit and don’t glue the pieces together. This creates a seam. You always see it, but this allows the wood to move a bit. We pre-fit the corner, but provide countertop fasteners for underneath the top to bring the two sides together.
Single Direction Tops
Because wood expands and contracts in width and not length, going a single direction with the wood can be a great way to solve the mitered corner issue. In many cases, this approach can add some nice character to the kitchen.
90 Degree Joints
The other approach is to use 90 degree corners rather than 45 degree (or there abouts). This makes the stress on the joint consistent and can be addressed in installation. This joint can be glued tight and works well, but is not usually aesthetically pleasing as the other methods.