Acclimation - Site Finished & Prefinished Solid Flooring
When you receive your flooring, we suggest that you let the wood acclimate to the moisture in your home for 10-14 days before installation begins. Longer periods are required for dryer areas. Atmospheric conditions cause all wood to expand and contract to a certain degree. It is also critical that your sub-flooring be quite dry before installation. In new structures, windows and doors should be closed in the evenings and during fog or rain. All sheet rock and masonry work should be completed and dry. These steps insure the least amount of shrinkage which causes cracks to develop.
The point of acclimating wood flooring before installing it is to allow the moisture content of the wood to adjust to “normal living conditions” at the site – that is, the temperature and humidity conditions that will typically be experienced once the structure is occupied. Thus, it does no good at all – in fact, it is likely harmful – to store wood flooring at the jobsite under conditions that don’t reflect those normal environmental conditions. The wood flooring industry has done a good job in recent years communicating the message that wood flooring is a dynamic material subject to changes in dimension as a result of changes in humidity in the surrounding environment. That has led to increasing awareness of the need to acclimate wood flooring before installation. Unfortunately, some installers have heard the message as, “Leaving wood flooring at the jobsite for two weeks will properly acclimate the wood, no matter what the conditions are.” In truth, some wood flooring may already be at the proper moisture content when it’s delivered. To allow it to sit at the job site under excessively humid conditions will only cause the flooring to absorb unwanted moisture. So, the key message is not that acclimation is good, and that’s all you need to know. Rather, installers need to understand the dynamics of water and wood and make educated judgments about when and how much acclimation is required. To do so requires knowing what the moisture content of the flooring is at the time of delivery and what its expected moisture content will be “in use.”
Acclimating the Wood...
If flooring is delivered on a damp day or during rain, the boards will absorb moisture. If installed in this condition, the flooring will shrink a few months later and show cracks. Wood flooring should not be delivered to the jobsite until plastering and painting are completed and dried. Moisture evaporates from damp walls into the air within the house, and the flooring will absorb some of it. Another condition that causes flooring to pick up moisture during construction is less obvious, but more common: If the heating or air conditioning is not operating from the time the floor is installed until the house occupied, the humidity may be higher than it would be if the house were occupied. Only after getting satisfactory moisture measurements from the concrete slab and the sub floor, and only after wood has acclimatized to the jobsite, is the installer ready to install. When installation is completed, good practice calls for a delay of one or more weeks for further acclimation before beginning the sanding and finishing part of the job.
Acclimating the Wood at the Jobsite...
Before wood is delivered, the jobsite must be checked to determine if it is ready. Wood should not be delivered if jobsite moisture conditions are excessive. Otherwise, one will absorb moisture from the other. The structure should be fully enclosed, with doors and windows in place, and interior climate controls should be operating for at least 48 hours to stabilize the jobsite, the wood should be set indoors on sticks up off the floor. About one week should pass before the flooring installation is started. Moisture contents of both the flooring and the sub floor must be checked and recorded before any work begins.
Solid (3/4") - Suitable for installation on or above grade only. Solid wood floors should be nailed and possibly glued, depending on the width(s). Wider boards (8" +) should be facenailed OR glued and blindnailed.
Engineered (5/8") - Engineered flooring can be nailed, glued or floated and installed above, on or below grade. Ideal for installation directly to concrete slabs and over radiant heat.