A is for acclimatisation

Sid Bourne, independent consultant.

Sid is often asked whether engineered wood flooring needs to be acclimatised.

This month, he addresses the question.

THIS column is a little different to the usual. I often get asked this question: does engineered wood flooring need to be acclimatised. I’ll delve deeper into this, but the only real advice when asked this, is that you should follow that manufacturer’s instructions.

The reason I say this is that I get involved in many disputes where a supplier or manufacturer says the problem with the floor (regardless of whether it’s delaminating or buckling) is acclimatisation – or the lack of it.

So, I’ll give you my tried-and-tested opinion. I’ve tested various floors with acclimatisation and the results I get are surprising. Most engineered flooring will be wrapped to help protect the ingress of moisture and preserve the kiln-dried product, but then other engineered floors I see are delivered with simple wrapping and part-exposed boards -  there’s no way this type of wrapping will preserve anything, so much depends on how the product is delivered or shipped to you.

One important thing I always say is: on delivery take moisture readings. It’s surprising how many times there’s an existing issue with high moisture in particular, and this is a problem with the delivered goods. As an example, I visited a supplier who was in dispute with the installer. The reason was that after the floor installation, gaps appeared throughout onsite.

‘Did you take moisture readings of the product?’ I asked the installer.

‘No,’ he said.

I measured the product and came to my own conclusion as to what had occurred. The supplier said he’d never acclimatised the floor. On seeing where the flooring products were kept, I was astonished most of the wood flooring was left outside the building, exposed to the elements.

I can tell you, hand-on-heart, while at the suppliers I saw the warehouse lads loading up a van with engineered flooring and using clingfilm to quickly wrapped the flooring, then off went the flooring.

Unless the installer at the other end knows his stuff, I’ll be expecting a call, I thought to myself.

Notwithstanding everything I’ve said, the manufacturer’s instructions override everything, but common sense will also play a big part in this.

It can be confusing for the simple reason that some manufacturers say acclimatise 48 hours or so and others say no, install straight from the packs. First, when working with wood always check everything. If you heat it up and it works, and if there are no plasterers or other trades onsite and if the subfloor is all as it should be, then in my professional opinion acclimatisation of engineered boards isn’t required.

Relative humidity plays a big part in acclimatisation (or not, as the case may be). If for example the moisture content is at a higher content you could have problems engaging the tongue-and-groove. If this happens, it may indeed need to be acclimatised.

I’m often told that: ‘We acclimatised the floor for more than a month or so.’ This, however, means nothing. Simply take the required readings, such as relative humidity and consider the seasonal changes, moisture check the flooring and you’ll have no problems. By acclimatising something for over a month means nothing as it will change as the humidity changes so consider what the overall building is being used for and whether there’s regular heating.

Now something I say to installers is to measure the face of the product they ordered. Check it’s within tolerance of the dimensions sold. If it isn’t, then the product is defective - don’t install it. This is particularly important if you arrive to install a floor for someone who’s had it onsite acclimatising. Measuring will tell you if the floor has been poorly acclimatised ie exposed to the elements or not.

Let’s face facts, engineered flooring was made to be hassle-free but still I see hundreds of complaints.

Providing you buy your flooring from a recognised manufacturer or supplier and the products are well packaged, then in my opinion you can in most cases install straight within 24 hours from the unopened pack, but you should still check moisture content.

Remember with top manufacturers the tongue-and-groove are precision milled, and any changes in moisture before installation will generally affect the installation of the tongue-and-groove and also uptake in moisture will also cause distortion of the boards.

One problem I see often onsite is that the wood is delivered all well-packaged, then stored directly onto screeded subfloors, which may have only been down for a few weeks. When storing keep the flooring off the ground and well supported. The floor needs to be at the same ambient temperature as the room. If you have differential temperatures, this will not allow the flooring to acclimatise if that is required by that manufacturer and will inevitably cause the boards to deform, owing to an imbalance of moisture (if left long enough).

Often, even when the floor is installed to perfection, the property is then neglected and exposed to incorrect relative humidity and temperature. It’s so important that after installation, the relative humidity and temperature is kept to within that manufacturer’s instructions to allow a natural process of acclimatisation.

The key to all this is (as I’ve stated so many times before that I bore even myself) to take the appropriate readings. This includes moisture content of the delivered product, relative humidity, temperature and subfloor testing. Document the results and get it signed by a witness. Doing this prevents comebacks if the floor has been mistreated after installation - believe me it works.

Now, as a wakeup call, I’ll relate this job from nearly 18 months ago. I was called to inspect a prestigious building with engineered Versailles panels about 1mx1m.

The installation was carried out by the building company (Bob, in case you’re unfamiliar with my old friend). Why didn’t the end-user just employ a professional wood flooring expert? Anyway, I was told the install and products cost more than £120,000 and was installed right through this prestigious building. The complaint was of gapping.

The gapping was more than 1.5mm on every panel. Bob had tried to fill the gaps but – surprise, surprise – had made a hash of it.

Onsite, I was shown where the panels were stored, in a lower ground, old cellar, which was to be made into a winery store eventually.

The panels had been delivered well wrapped but had then been unwrapped by Bob for easier handling. They’d been kept in this unheated cellar for more than two months before installation. Bob told me the panels were extremely difficult to get together, but other than random small gaps the floor was fine. However after several weeks large gaps appeared – shock, horror!

I measured the panels, which were now at the milled dimensions. The cause? The product was acclimatised to a much higher moisture content owing to poor storage and incorrect storage, installed and now exposed to the normal living conditions the panels were contracting, leaving large gaps.

The outcome was that the flooring in its entirety had to be replaced. There was nothing to be done to prevent this replacement and it was all down to incorrect acclimatisation. In reality Bob should never have taken on this installation; he should’ve employed the expertise of a flooring expert installer, who would’ve immediately prevented this disaster.
Lesson learned.