Hardwood floor acclimation is also referred to as acclimation, acclimatization or wood conditioning. It is a pre-installation process for hardwood floor. The process involves giving the materials time to adjust to the change in its new environment. The hardwood should adjust to the humidity and temperature of the sub-floor in the job site.
Why Do Hardwood Floors Need acclimatization?
Wood is hygroscopic. As such, it tends to absorb moisture from its surrounding environment or lose moisture depending on the humidity levels of the surroundings. Wood flooring materials will expand due to retaining moisture when the environment is humid. On the other hand, when moisture is low wood contracts.
Because hardwood floors are hygroscopic, they perform better in some environments than others. They perform best in an environment with temperatures of between 60 to 80 degrees Fahrenheit. Wood floors do well in humidity range of between 35% to 50%.
In this regard, the hardwood acclimatization process gives the materials time to reach an equilibrium moisture content (EMC). There is a moisture content balance between the hardwood and sub-floor. Acclimation considers mainly two factors, first, the climatic conditions of where the wood came from. Secondly, the climate conditions of where you are installing the hardwood floor. Acclimation prevents structural damage, excessive shrinkage, excessive expansion, or dimensional distortion.
Moisture Content Guidelines
A moisture meter is a tool for comparing the subsoil or sub-floor of the job site with the moisture content in the hardwood. There are wood moisture meters and concrete moisture meters. The moisture content between the sub-floor and the hardwood should only differ by between 2% to 4% depending on the size of the hardwood materials you are installing. Thin hardwood planks that are below 76mm should not have more than a 4% difference in moisture content with their environment. On the other hand, wider planks above 76mm should only have a difference of 2% with its environment.
It is advisable to follow the manufacturer’s instructions on hardwood acclimation. But if there are no conditioning and acclimatization instructions, here is what you can do.
Hardwood acclimation Steps
There are two main steps of hardwood acclimatization process. First you should prepare the environment at the job site. Secondly, prepare the hardwood materials. Because both the job site and the wood have to be ready for installations.
1. Preparing the Job site Environment
You should install the hardwood flooring materials in normal conditions expected in the environment. Also, humidity levels should comply with recommended levels which are between 35% to 60%.
If the hardwood flooring materials absorb moisture from the environment and you install them with high moisture levels, after installation, they will shrink until they reach their EMC. As a result, there will be wide spaces and gaps in the flooring. On the other hand, hardwood floor will expand to reach their EMC after installation if coming from low humidity.
Therefore, to control humidity levels, only install hardwood flooring materials when they are at an EMC. Moreover, you should also put in mind any expected seasonal change in climatic conditions at the job site before bringing the materials in.
To control the acclimation process, the hardwood floor installations should come last when constructing a building. In this regard, the following building constructions should be completed before hardwood flooring materials are delivered to a job site:-
- The premises should be enclosed by ensuring that windows, doors and the HVAC are in place.
- All wet constructions should have been completed. You should deliver the hardwood flooring materials only after the sub-floor and the wall painting are dry. Otherwise, the hardwood flooring materials will absorb the moisture in the paint or sub-floor which will cause expansion.
- Additionally, the air conditioning and heating systems should be in place for about a week’s duration before you can plan to deliver the hardwood materials.
It is only after the job site is ready for the wood, that you should plan to deliver the hardwood flooring materials to the premises. Moisture measurements of the sub-floor and concrete should comply with standards before delivering hardwood flooring materials. Now you can follow your manufacturer’s recommendations about acclimatizing the hardwood flooring materials you bought.
2. How to acclimate Hardwood Flooring Materials
How long should hardwood acclimate before installation? Various factors influence hardwood acclimation period. The factors include the hardwood tree species, the job site’s climatic conditions, and whether the tree species is exotic or domestic. Please note that exotic wood species require more time to acclimatize because they have a high content of oil and resin and they are denser.
Both engineered hardwood and solid hardwood flooring materials need to acclimate unless the manufacturer prohibits it. Going on, wood flooring materials should stay at the job site for at least three days before installation. However, the best acclimation test is measuring the hardwood’s equilibrium moisture content.
The process starts with measuring the wood moisture to establish a baseline as soon as you deliver the materials, and writing down all the measurements. It is best to take samples from different boxes of the materials for an accurate measurement. You then need to monitor the acclimation of the wood flooring materials by continuing to take its moisture content on a daily basis. For fast acclimation, encourage air circulation by spacing and cross-stacking the hardwood materials.
What happens if you don’t acclimate hardwood floor? Failure to acclimatize your hardwood flooring materials or prepare the job site for the materials can result in flooring failure. If you fail to do the process right, it can result in the wood floor cupping, warping, buckling or having excessive gaps after installation. In fact, failure to follow the manufacturer’s acclimation instructions can void the warranty on the materials.