Our Engineered Oak Wear Layer Explained
The wear layer of an Engineered Oak board is the top part that you walk upon when it is installed. It is called the ‘wear layer’ because it is the part of the floorboard that will become most ‘worn’ during usage when it’s walked upon.
Many companies choose to bond the wear layer to a softwood or MDF underside but this does not provide sufficient strength and stability for many installation situations.
A plywood underside, especially Eucalyptus or Birch, will provide excellent stability. Naturally, the more plies within the plywood results in better stability of the wear layer.
Many companies describe the plywood they use as Birch but often it is a mix of Birch and something like Poplar, which reduces its effectivity of resistance to dimensional movement.
Some people worry that Engineered Oak is not as durable as Solid Oak and as such will not last as long but the oak wear layer is produced from exactly the same oak as the solid.
As long as the wear layer of oak is substantial enough, it will last for many years (a 4mm wear layer product can last more than 50 years in some situations like bedrooms etc, where traffic is not heavy).
Engineered oak is usually described in a 2 figure format like 14(3), 15(4), 20(6) or 21(6). The first number refers to the overall thickness of the board whilst the number within the brackets is the thickness of the actual wear layer of oak.
Of course the thicker the wear layer, the longer the oak flooring will last. The minimum wear layer for our engineered oak is 4mm on our 15mm flooring, so it is described as being 15(4). The board width is currently 189mm.
Our 21mm flooring is 21(6) with a full 6mm wear layer. Widths available are mostly 189mm but we also supply a 240mm wide board with the 21mm structure as unfinished.
Many people get distracted by the number of times a wear layer can be sanded when it requires repair or maintenance to enable refinishing. This concern is generated by the way that oak flooring was finished when it first became a popular floor covering. Most was either varnished, lacquered or waxed. This meant that when a floor needed to be refinished or repaired, the whole area would need to be sanded completely to remove all the existing covering, so that new lacquer, varnish or wax could be applied. These types of finish cannot be patch-repaired and unless the old covering is completely removed down to bare wood, then the new will not adhere to it sufficiently.
Sanding this type of finish means that some of the oak itself will be also removed. With an oiled or waxoiled floor finish, maintenance becomes a lot more simple and easy, although it may well require maintenance a little more often than a fully lacquered floor.
Oiled oak flooring should not require the use of industrial sanders to remove the existing oiled finish and can usually be simply sanded by hand or with a small hand-held sanding unit sufficiently well to accept the new finish coat (of course this new coat must be the same type of finish as what’s already on the flooring).
This means that an oiled finish will last much longer than a lacquered finish when maintenance and repair is taken into consideration because there is no need to sand it down to bare wood.
Another factor to consider when sanding is on the agenda is that an 18mm thick solid oak does not necessarily last longer than an engineered oak. Any Tongue & Grooved flooring product can only be sanded down to where the T meets the G. An 18mm solid oak floor board has approx 6mm of wear layer before this happens. This means that our 21(6) engineered oak has as much ‘wear capacity’ as the solid oak does, whilst providing much better stability and our 15(4) product isn’t far behind. Do not confuse overall thickness with wear layer.
This leads on to why we stock a minimum wear layer of 4mm when many other companies supply 3mm or 2mm wear layered products. We believe that when manufacturing and material costs are considered, having a thinner wear layer than 4mm is false economy. Not only will anything thinner wear out faster but it also reduces the overall thickness of the board itself, sometimes resulting in more ‘give’ or ‘bounce’ when the finished floor is walked upon, making it feel unlike an oak floor.
The 15(4) product thickness is also great for installing over Underfloor Heating because its thermal resistance is sufficiently low to allow the UFH system to work effectively and efficiently, whilst possessing sufficient strength to feel like a solid oak floor when installed.
Although our 21(6) product is also suitable for installation over UFH, because of its structural strength and thickness, it may reduce the efficiency of the UFH output.
Also, with the 21(6) product, because the 6mm wear layer of oak is so strong, unless humidity levels are monitored and controlled, during prolonged very cold periods it can be forced to lose moisture, resulting in it pulling away from the plywood underside. This is not a product fault because the oak is simply acting as any natural hygroscopic material. All it is doing is trying to seek sufficient moisture to regain its acclimatised moisture content.
Sometimes the 21(6) thickness is required because it’s classed as structural grade, so can be installed over joists that are themselves fixed at a maximum of 400mm centres without any further subfloor support between for the flooring. When UFH is present in this installation situation, we advise the implementation of a Thermo-Hygrometer, which will constantly monitor the temperature and Relative Humidity that surrounds the oak flooring. When the Relative Humidity becomes too low, moisture needs to be introduced into the air by way of portable units or other such devices.
Which thickness and wear layer combination you choose will depend on a number of contributing factors and question;
- How long you want your flooring to last?
- Your available budget?
- Your chosen finish; lacquered or oiled?
- Where it is being installed; the amount of traffic it will receive?
- Is it being installed over UFH?
Some things to be aware of that can have a negative impact on your new oak floor’s performance and your overall experience are;
- Insufficient or incorrect advice from the supplier before purchase
- Insufficient or incorrect installation guidelines for the purchased product
- Insufficient or incorrect maintenance guidelines
- Insufficient or incorrect after-sales support
- Sufficient and correct information supplied but a failure to follow it
Whatever the combination though, try to choose a high quality plywood backed engineered product because you will experience far less challenges after installation.
- Wherever you buy your Engineered Oak Flooring, we want your project to go well during installation and also for the performance of your finished floor to be as you expected.
- Any problems that arise through challenges you experience can affect the wood flooring industry, so ultimately they will also affect our future business, even if you have not bought your flooring from us.