Each floor is part of a building system and the performance of the floor is dependent on other elements within the building. The key element which influences the way a timber floor will react is moisture. As mentioned above, wood is hygroscopic, absorbing and releasing moisture to and from the air depending on the temperature and relative humidity of the air. This loss, gain or redistribution of moisture creates visible movement. You can expect your floor to move to some extent. You can expect fine gaps to appear from season to season, especially in rooms which experience unusual or significant changes in humidity and temperature (both from heating and sunlight).
The moisture content of timber in a building moves towards the Equilibrium Moisture Content (EMC) of that building. EMC is a function of the average temperature and relative humidity of the building.
In general, floating floors will react more to a high EMC than direct fix floors and moisture problems can result in cupping and/or swelling. When the EMC falls back within the range, cupping and shrinkage should correct itself.
Bathrooms and laundries can often have higher EMC´s. In these areas, the timber should be well looked after and the following steps should be taken to keep the EMC within an acceptable range.
- • Prevent water leaking from washing machines, shower doors and other plumbing fixtures.
- • Do not leave puddles of water, damp towels, bathmats or clothes on the floors.
- • Use extraction fans and heaters, as well as heated towel rails.
If the house is being maintained at a comfortable temperature and relative humidity, then the EMC should not go above 13%. Moisture content above this usually indicates a problem such as inadequate ventilation, moisture egress from the subfloor or plumbing or drainage problems.
Please be aware that there are potential problem areas within a house where the floor may be more likely to take on moisture. This may result in expansion, possibly damaging the finish – for example by the base of external doors that do not have adequate door seals; rooms on the south side of houses which are seldom used and are unheated during winter; doorways with immediate access to the house from swimming and spa pools; underneath dishwashers which accidentally drip; potentially “wet areas” such as bathrooms and laundries as previously discussed. It is not recommended that a house is left unheated for long periods during winter, as the EMC will rise without the drying effect of the heating and venting associated with normal occupation.