Installation of edge-grain solid wood countertops
For a long-lasting, great-looking wood countertop, bar top, or kitchen island top, some specific directions concerning storing, installation, and maintenance must be followed. Failure to comply with the prescribed procedure might trigger damages that are not covered by our warranty.
Storing and handling
Ideally, boards should be stored flat against the ground. If the boards are stored on level supports, please ensure the supports are evenly distributed along with the boards. In a tight space, you can also store the boards leaning against the wall at a pretty sharp angle. Do not store the boards outdoors, in an excessively dry or moist environment, or near a heat source.
We also recommend that the protective plastic sheet not be removed too long before installation and cutting.
Large wooden tops are usually quite heavy, so please handle them with care to avoid injury and damage to the product.
Oiling the top
Solid wood tops should be finished before installation. The finishing we supply along with the boards is food-grade mineral oil, and ecological, a biodegradable product specially designed for this type of application. The mineral oil is versatile, easy to apply, inexpensive, and offers proper overall protection.
For the mineral oil to seal the wood pores effectively, it must be applied correctly. Please follow these instructions:
- Using a paintbrush, apply the oil abundantly onto the wood surface. Insist on the end-grain area, where the pores are wide, and the wood is more prone to absorbing moisture. Make sure the oil is applied evenly on both sides of the wooden top.
- Let the wood absorb the oil into its fiber. Depending on the wood type and the environmental conditions, this process can take between 1 and 6 hours. The Proterra oil we supply is one of the fastest absorbing oil finishing. If you choose to use tung oil, teak oil, or walnut oil instead, please note that these products usually take longer to cure.
- Repeat the process for the second coat of oil. Allow drying, and then apply the third coat. At this point, the wood should be soaked in oil, and you should allow it to dry overnight.
- Remove the excess oil with a paper towel or a clean cloth, and your top is ready for installation.
Attaching the top to the cabinet box
The solid wood top must be attached to the cabinet box using only wood screws and washers. Do not glue the countertop on the cabinet box. The top and the box expand and contract at different rates; therefore, cracks might eventually appear, most probably on the cabinets’ surface.
The proper way of installing a solid wood top is using metal fixings along with the cabinet box, as shown in the drawing on the right.
The metal fixings must be uniformly distributed throughout the length of the top, spaced at a 1′ – 1.5′ distance from each other. Across the width, the top is usually fixed to each metal support with three screws, one in the middle, one toward the front edge, and one toward the rear edge. The supports must be perfectly leveled; otherwise, tensions can develop in the wood, leading to warping, cupping, or cracks.
We recommend pre-drilling the screw holes into the wood countertop, to avoid cracks and splits. For the same reason, it is a good idea not to over tighten the screws.
Wood displays natural movements, usually following changes in the environmental humidity. The finishing will considerably diminish the extent of such actions, but will not eliminate them. Due to the panel’s laminated structure, the lengthwise movements are negligible, so the installer should pay attention to the movements occurring across the panel’s width. To prevent inner tension development, the holes in the metal fixings should be elongated in the direction of the movements (see picture).
When the rear edge of the countertop is installed against a wall, it might restrict the top’s natural movements, leading to undesired tensions in the wood. To avoid this, you can allow a 5-10 mm joint between the wall and the countertop edge and caulk it with a thin bid of acid-free silicone. Additionally, you can firmly fix the rear edge to the metal supports underneath and allow the natural movements to occur at the expense of the opposite side.
In this case, the holes in the metal fixings corresponding to the rear edge will be no larger than the diameter of the screws. The holes corresponding to the middle section and the front side will be elongated as previously shown.
Joining two sections of a solid wood surface
This is a pretty straightforward operation that can be quickly done by press-gluing the boards. All you need is a suitable adhesive and a perfectly flat surface. If the total width is not too big, you can press the boards using clamps; alternatively, you can use bolts and washers attached on the bottom side, as shown in Drawing #2.
The panels’ edges are straight, at a perfectly straight angle, and the lamellas all have the same width. Consequently, if the boards are appropriately pressed, the seam will be invisible. After the seam is cured, the gauge hiding the bolt can be covered with silicone caulking. Additionally, a few biscuit joints along the seam will grant extra stability.
A sink insert is usually associated with increased moisture. Therefore, regardless of whether the sink is over mounted or under mounted, the edge grain of the sink cutout must be carefully sealed, using a polyurethane-based lacquer or varnish. Mineral oil finishing might not always grant the necessary protection for this area.
The sink’s edges must be adequately caulked to prevent water infiltration between the sink and the wood surface. For configurations stipulating multiple sinks, the distance between them should be kept to at least 8″.
We do not recommend allowing unsupported ends longer than 1.5′. The average specific weight of the hardwoods species we promote is about 46 lb/ cubic foot, so the unsupported section might, over time, bend under its weight.