This is the time of year where people start to notice seperations between planks in their hardwood floors. Depending on the species, colour, width, and format of your hardwood flooring product, these separations can be slight (less then a credit card in width) to gaps that are more noticeable (fits a toonie).
Wider boards have more surface area so variations in width become more noticeable, and should be expected.
Light floors (example, Maple or Birch) tend to show the separations more due to the light colour of the field being broken by the separations appearing as dark lines.
Site finished floors tend to show movement more due to the smooth, flat surface of the wood as opposed to prefinished floors which have a micro-bevel around each board.
This separation is due to the wood shrinking with a change in the relative humidity in a home or commercial space.
Alberta is considered a very extreme environment as our relative humidity levels can swing drastically from 100% humidity in the summer to 10-15% in the winter. Since wood is still reactive to changes in temperature and humidity due to the open vesicles within the wood that can absorb and release moisture, it is imperative that homes and offices be kept within a range of acceptable RH in order to minimize movement.
A quick note on engineered products: It is true that engineered products are more stable then solid products. Having said that, engineered products are still susceptible to changes in RH. The top surface or wear layer of an engineered product is solid hardwood, and the structural layers beneath it are made from a stable plywood core (in most cases), the hardwood can exhibit a cupped look when RH levels drop below optimal levels.
We recommend to our customers to try and keep the RH in their homes between 30 and 50% year round. We realize that this can be difficult in the winter months trying to strike a balance between a constant RH and frost on your windows. However, if the RH falls below 30%, you can expect the separations and board movement to be more noticeable and in some cases, can void the warranty on some products. In extreme cases (RH below 20%), the cupping can become a structural issue and the floor may not flatten out again, even when the RH levels increase to an acceptable level.
We recommend that all home owners have a flow through humidifier installed in their home and talk to an HVAC expert about running a two stage fan in their furnace. The flow through humidifiers are able to properly humidify your home and will help keep the RH level within the acceptable range. In most cases, seasonal movement will correct itself as the seasons change.
It is important for customers to know that wood is reactive to moisture and movement will occur. It will not detract from the look and overall aesthetic of a beautiful hardwood floor. With proper maintenance and care, a properly installed hardwood floor should last a lifetime!