Richard Renouf points out that laminate must be free to expand and contract just like wood, and advises contractors to check the product’s suitability before starting to fit it.
‘THERE’s more wood in this than if it was solid wood.’ I must’ve said that 100 times this year already when inspecting a laminate floor, and I say it to emphasise that laminate must be free to expand and contract just like wood.
I hold my hands out to indicate a depth of 450mm (okay, it’s 18in in old money, I’m old enough to say that!) and move them together as if I was crushing a pile of sawdust as I explain to the customer – or installer – how laminate is made to help them understand how critical expansion is to the product, and the usual response is surprise.
It’s easy to assume such things will be obvious, especially to installers, but it isn’t. At least, not when your job involves looking at flooring failures, so you’re dealing with the consequences of misunderstandings.
And now the use of click LVT and stone composite tiles are becoming more common, so are the assumptions that it should behave like the previous flooring, whatever type that may have been.
Joints are the most common example, probably because it’s the joints that are likely to show the first signs of any problems. As soon as they begin to show crease lines or pop up after use, it’s always assumed to be the fault of the manufacturer.
‘I noticed they were flimsy when I put the flooring down.’
‘It doesn’t matter how often I press them back together, they still keep popping open, so they must be faulty.’
‘This never happened with the laminate flooring I had before.’
No-one, it seems, stops and considers that the joints are machined about of a tile that’s maybe 3mm thick, and to create a locking profile this requires some of the edge profile to be less than 1mm thick. That’s more than adequate to hold the joints together from side-to-side to prevent the tiles coming apart, but it isn’t strong enough to create a joint that can take vertical pressure. And if the tile has a stone or mineral core (a rigid LVT) then the profile is even less flexible and can break very easily.
Let’s put that in practical terms:
Click-together flooring needs a flat subfloor. BS 8203: 2017 defines the basic requirement: ‘surface regularity 1 (SR1), which means you shouldn’t be able to get an old pound coin under a 2m straightedge. However, some manufacturers know, after testing, that their flooring can cope with a floor that isn’t as flat as this and they’ll set out what’s needed in their fitting instructions. For laminate, it’s commonly 2mm over 1m.
But for some rigid LVT floors the floor must be to a higher standard, sometimes no more than 5mm over 3m. It’s the floorlayer’s responsibility to check the instructions for what they lay and if they miss this basic requirement, failure, and the associated cost, is likely. The use of a self-levelling compound doesn’t guarantee the floor will meet this standard. It can do, but only if the compound is applied correctly.
Click-together flooring needs the right underlay, if any at all. Some rigid LVTs have a thin underlay built into the product and nothing else should be used. LVT tiles are more flexible than laminates and wood flooring, so when you walk on them your weight is applied over the area of your foot, whereas with laminates your weight is spread across the area of the plank, and perhaps a bit further, and this means laminate underlays can be softer to improve noise reduction. Put a laminate underlay under an LVT floor and the joints will break very quickly.
Click together flooring needs to be free to expand and contract. This means, like laminate and floating wood floors, a minimum expansion gap must be left all around the flooring, and at intervals if the length or width exceeds the maximum size stated in the fitting instructions.
The width of the gap varies, usually between 2-15mm, but the instructions will make this clear. And the gap must be left everywhere, including along floor-level window and door-frames and around the feet of kitchen units and décor panels. Kitchen units and wood-burning stoves should not be fitted on top of a floating floor.
A few weeks ago I examined some flooring in the home of the owner of a wood-burning stove company. He’d installed a stove when the floorlayers had gone and so I had to talk to him about the problems this created. He gave me two useful pieces of information. First, to dismantle a stove to replace flooring and then to reinstall it’ll cost an average of about £500. Ouch.
Second, there are two types of hearth: the flat slab which we seem to come across very often and the alternative, a slab with set back feet that will allow flooring to be fitted underneath to leave an expansion gap. He had the luxury of being able to change his hearth easily, but it would be another cost for the average customer.
And while on the topic of expansion, it’s always worth remembering laminates expand and contract with changes in ambient humidity, while LVT is affected by temperature. In front of south-facing windows and in conservatories, heat can build up to well over 50deg C on a reasonably sunny day, so check the product’s suitability before you start fitting it.
www.richard-renouf.com
