Times of highest concern: May – August. We have discussed in previous Tech Bulletins (#11 ‘Winter Gaps in Floor’) how winter effects timber floors that are already installed. This particular Tech Bulletin is going to point out some essential tips to remember when INSTALLING a floor during winter.
WHAT ARE THE CONCERNS?
With everything drying out in colder months (like your lips) it also dries out timber floors. This removes the moisture in the product and as a result ‘shrinks’ the floor boards (see diagram). This can also have the same effect on laminate, hybrid and engineered timber floors.
Whilst shrinking is normal and isn’t necessarily a problem, if boards that have already shrunk are installed tight, you will have possible major issues come summer time when they expand again.
These issues include ‘cupping’ / ‘peaking’ or over expansion, it could even result in the boards lifting up off the floor (see image).
HOW TO AVOID THIS?
All flooring products are made to be an exact size in the width and particular moisture content, for example in diagram 1, the standard size of the board is 80mm wide at a moisture content (MC) of 11%. When conditions are dry, this board is expected to shrink possibly down to 79mm and 8% MC, but when humidity increases they may grow to as much as 81mm wide or 16% MC.
If the boards that are about to be installed are normally 80mm wide, but are only 79mm at the time of the installation, they will then have no room to grow to 81mm when the humidity increases, thus causing cupping.
To avoid such issue, the width of the boards or moisture content should be checked prior to installation, ideally using measuring callipers or a timber moisture tester (see image). If they are measuring much lower than the standard size or MC then there are two things that could be done to avoid possible problems.
1. Allow boards to acclimatize back to their normal size and MC before installing. This can be done by stacking the flooring on-site or unboxing all of the flooring and conditioning the environment. This could mean placing buckets of water in the same room to allow it to evaporate into the environment which would then be taken up by the flooring, ‘growing’ the boards back to their standard size.
Other options could be the use of humidifiers or air conditioning that can be set to a mode that does not dry the air out. Continue to check the width and MC of the boards until they have stabilized before installation begins.
2. If time does not permit to allow the flooring to return to normal before installing, there is another method that could be used. The use of ‘control joins’ in the floor could then be the best method. Control joins are when very small 1-2mm gaps are left purposely in the floor every 1 metre or so. This is to be done with extreme caution or only after consultation with a flooring expert as if done incorrectly it could cause other issues.
Adhesive and coatings are normally ‘moisture cured’ products meaning they require moisture before they start curing. In drier periods of the year it can also mean that drying times for adhesives and coatings can differ. Allowing more time for adhesives to set is essential and following our tips in Tech Bulletin #10 – Coatings & Winter is also essential if sanding and coating the floor in winter as well.
For more technical information please contact the team at Marques Flooring.