What is Acclimatization?
Acclimatization is a process for raw unfinished timber that needs to be installed in a house or other internal location. This is a very simple process often overlooked in timber flooring. It is vitally important to successful floor installation.
Timber naturally adjusts to its environment. It does this by taking on or losing moisture in accord with the environment in which it is at the time. So if timber is going to be installed into a house it will adjust it’s moisture content to match the average moisture content in the air in the house. There is a surprisingly stable moisture content in the air in dwellings that are occupied. It does vary quite a lot during the day but the averages from day to day are quite consistent and timber doesn’t react so quickly that these variations will affect it greatly.
It is important that the adjustment occurs naturally before the timber is installed. Virtually all mills provide direction that their timber should be acclimatized before installation. [If you don’t you cannot go back to the mill and raise an issue.] Otherwise it can cause gaps and cupping in the floor: this would spoil the appearance of the flooring.
The process of acclimatization can take anything from 1 week to 3 weeks depending on species and situation. This applies to all houses that have been occupied and have therefore adjusted to the livable habitat.
If the house is brand-new then a natural climate has not been established. In this case there is no benefit in bringing timber to site and installing it after a period of acclimatization. The timber should be installed quickly if the floor is to be installed in a house that is not occupied. The timber purchased for a new dwelling should have a kiln dry certificate of Moisture Content commensurate with the local average.
Alternatively site testing with slow ‘new builds’ may indicate that the area is close to the local norm but this can only be measured against the EMC chart.
At VCS we use a testing procedure to check the condition of the house. Once we know statistically and measurably that the house has reached equilibrium we can then ensure that the timber comes into equilibrium with the house. This is the only accurate way to achieve acclimatization.
NOTE RE OTHER TYPES OF FLOORING
The process of acclimatization applies only to raw timber that does not have finish applied to its surface. Engineered floors and pre-finished flooring cannot effectively be acclimatized to their surroundings and therefore do not require the same process. This means that pre-finished timber can only successfully be installed in areas that have an EMC that is within plus or minus 1% of the MC of the pre-finished or engineered flooring.