So. You’ve managed to get the new house to ‘lock up’ before the summer holidays begin. You look back at the work you’ve done so far. The Vic Ash windows look great. The entertaining area will be a great selling point. The timber floor is a beautiful addition. Before you close the door, you reflect on all the work it took to reach lock up on time. The house looks fantastic.
After the scorching summer break you return. Sporting a singlet tan, the Aussies have won the Ashes, you finally finished that job you said you would but wait… whats this?? The floor boards have shrunk!
Unfortunately this is an all too common feeling across the country just after Australia Day.
You see, timber flooring sold in Australia is kiln dried to a rooms optimum EMC (equilibrium moisture content) as advised by the Australian Standards (AS2796). While this is acceptable, we are generally able to dry with a closer consistency of 9-10% moisture content exceeding recommendations. This means the floors are perfect for homes with an EMC of 9-10%. When laying a floor, the floor layer should always consider the in use conditions of the floor. If the home is based in a high humidity area where average EMC would be higher than 9-10% MC, time should be allowed for the boards to expand. If the area is lower in humidity than 9-10% MC then the boards will need to contract.
Newly built homes, left locked up over summer often have the same thing in common. Large windows with no curtains, lack of air flow, high temperatures, very low humidity. Even if the windows aren’t the size of the Rialto, generally speaking, heat can find its way in to reduce humidity which causes the boards to contract as they meet the rooms EMC.
The ATFA (Australian Timber Floor Association) are the peak body for floor layers in Australia. They have some great documentation on how to predict the EMC of a floor and many tips on how to avoid or fix any problems you may come across. While you need to be a member to access the majority of these documents, the following link will give you what you need.
scroll down to where it says ‘Acclimatisation of Solid T&G Flooring” and click the download PDF button.