Timber Flooring is a delicate product as it is a natural product that expands and contracts with seasonal changes and is also affected by the moisture content of the air. It is important to remember it is not in any relation to other types of flooring such as tiling or carpet, as timber is an organic material that is going to be affected by the climate around it.
Acclimatisation is making sure the timber floorboards are ready to be installed safety, it is the process of allowing partial equalisation of the moisture content of the hardwood timber flooring when supplied, to the moisture content of the surrounding environment where the timber is to be installed.
The moisture content of timber can be defined as the percentage weight of water present in the timber in comparison to the weight of the wood with all the water removed. A timbers moisture content varies with changes in temperature, humidity in the air that the timber’s climate is in. Small seasonal changes in timber floors are considered normal and small gaps that open up during dry periods are not considered a defect, in theory boards that may gap in hotter periods of the year will close in the colder and higher humid times of the year.
Timber Supply
Many customer’s of timber flooring companies may be a victim of buying timber which has been poorly kiln dried and has not settled down, thus down the track will result in inevitable shrinking or cupping depending if the wood is too dry or too wet. To minimise the movement of your timber floor caused by swelling on moisture uptake and shrinking on moisture loss, it is important to lay boards that are close to the average moisture content of the environment in which it is to be laid. This can only be achieved when the timber is properly kiln dried by its supplier, this involves a lot of time and care to make sure the boards have been dried as naturally as possible and they will not be unstable which occurs when timber drying is rushed by some larger corporate companies.
When choosing your timber request certificates of authentication for moisture content from your flooring contractor or builder to make sure the timber you are paying for is worth the money.
Engineered timber flooring (pre-finished) is sealed earlier and tends to be a far more stable in regards to changing moisture than in comparison to organic raw solid flooring that has not been sealed. Therefore acclimatisation is not needed when installing engineered boards.
Site assessment
All building or residential sites require climate assessment prior to the installation of a timber floor. It is important to know the long term relative humidity for the area where the floor is to be installed, such as if you acclimatise a timber floor for a household in the wet season, you will find in the hotter seasons the floor will dry out and shrink, so it is good to keep a fair balance. Relative humidity (RH) is the major influence determining whether solid timber flooring will absorb moisture from the air and swell, or whether it will lose moisture and shrink.
To some that point up, If the moisture content of the timber floor is close to the average long term relative humidity for the area then succeeding seasonal changes will be minimal. However, if the long term relative humidity for the area is significantly different from that of the timber flooring, seasonal changes in the moisture content of the floor can create problems. Local site climates for your area zone can sometimes be found by the bureau of weather meteorology in your state. For example for Australia site climate can be assessed using data from the Australian Bureau of Meteorology website at http://www.bom.gov.au/climate/data
Where seasonal variations are greater, seasonal movement (shrinkage and swelling) can be expected to be greater also. Areas that experience high levels of seasonal variation require greater allowance for floor expansion at the time of installation.
The building site or place of work should also be assessed for adequate sub-floor ventilation. This is a very important factor in reducing expansion and cupping of hardwood timber flooring. Where humidity beneath a floor remains high, the boards will cup on the surface where you walk as a result of the timber absorbing moisture from the humid air beneath. Timber is like a sponge it soaks up water and spits it our just as fast.
Your States Moisture Content Percentage
It is important to be aware of the right moisture content {7871f4c91f79cbddef59511eb5b9899c6f1d497baab0afdeab5a98ee6e504626} for the geographical location you are situated in. A base or all round figure is generally known by the timber flooring contractor you employ and varies 6-10{7871f4c91f79cbddef59511eb5b9899c6f1d497baab0afdeab5a98ee6e504626} from state to state in the US. In Australia moisture content of the wood depends on which state you are in also, for example Western Australian residents should be expecting a moisture percentage of around 9-11{7871f4c91f79cbddef59511eb5b9899c6f1d497baab0afdeab5a98ee6e504626}, in the Eastern States that figure changes from 11-13{7871f4c91f79cbddef59511eb5b9899c6f1d497baab0afdeab5a98ee6e504626} which is fairly large amount. Where the average supplied moisture content of the flooring is near the expected moisture content of the area where you live, acclimatizing your floor is not necessarily required. As the process has already been completed by the wholesaler.
Where conditions are drier, such as isolated inland areas or air conditioned buildings, or where conditions are humid, such as in coastal areas or higher regions, flooring may need to be acclimatized on site. The proper time frame for acclimatization of timber for that job is 2-4 weeks, not 3-6 days like some may think.
Stacking of Boards to Ensure Moisture Acclimatization
When storing timber floorboards for acclimatization for that job, if the timber is stack all on top of each other to timber in the middle of the stack will not be able to breath, hence only the outer boards will change is moisture content to suit the surrounding humidity and conditions. Please note that the rate of moisture uptake varies from species to species.
A criss-cross method is recommended to make sure every boards receives good air ventilation so that when the floorboards are installed they are all ready and will not be unstable in their environment.
