Solid wood countertops are natural products made of wood; wood is a living material and the more moisture receives, the more the wood countertop will expand. The wood we used in solid wood worktops has been previously kiln dried to a humidity level of 6%, and it is therefore important that the worktop is not exposed to a constantly high level of humidity. Normally the humidity level in kitchens is approximately 50-70%.
The solid wood top must be attached to the cabinet box using only wood screws and washers. It is not recommended at all to glue the top 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 the cabinet box.
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, in order to avoid cracks and splits. For the same reason, it is a good idea not to over tighten the screws. The finishing will considerably diminish the extent of such movements, but will not eliminate them altogether. Due to the panel’s laminated structure, the lengthwise movements are insignificant, so the installer should pay attention to the movements occurring across the panel’s width. In order to prevent the development of inner tensions, the holes in the metal fixings should be elongated in the direction of the movements.
When exposed to normal humidity levels – i.e. 50-60% – the worktop’s width will expand by 1/12”-1/24”, but when exposed to a level of 80-90%, this measurement may expand by up to 1/2″ or even more for some species. Therefore, when the rear edge of the counter top is installed against a wall, the wall might restrict the top’s natural movements, leading to undesired tensions in the wood. To avoid this, you can allow a 1/4”-1/2” 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 thus, allow the natural movements to occur at the expense of the opposite edge.
In this case, the holes in the metal fixings corresponding to the rear edge will be no larger than the screws diameter, while the holes corresponding to the middle section and the front edge will be elongated.