Engineered Wood Wear Layer: 3 mm, 4 mm or 6 mm
The wear layer is the oak you walk on and sand. What 3, 4 and 6 mm mean for refinishing, for underfloor heating and for the price of a board.
An engineered board is a layer of oak bonded to a core. The oak on top is the wear layer, and its thickness is the one number on a specification that decides how long the floor can go on being a floor. The range carries three: 3 mm on most 14 mm boards, 4 mm on the 15 mm Victorian Antique boards, and 6 mm on the two 20 mm boards. This guide is about what those numbers buy.
The three thicknesses in the range
3 mm is the wear layer on the 14 mm Ascot, Cobham and Weybridge boards, on the Oxford herringbone blocks and the Knightsbridge chevron boards, and on the walnut boards. It is the standard for a domestic floor and the largest part of the range.
4 mm is the wear layer on the 15 mm Victorian Antique boards at 220 mm wide, and on the Versailles panels. The extra millimetre is there for the deep brushed antique surface, which can be re-oiled and sanded more than once without losing its texture.
6 mm is the wear layer on the two 20 mm Victorian Antique boards. It is the thickness at which an engineered board can be treated like a solid one for refinishing, and it comes with the range's longer 20 year manufacturer's warranty. The antique oak boards carry both of the thicker options.
Wear layer and underfloor heating
Every engineered board in the range is listed as compatible with underfloor heating, whatever its wear layer, and none of the solid boards is. What limits wood over heating is the surface temperature, and the trade guidance that ties wood floors to a temperature limit is quoted below. A thicker wear layer is not a disadvantage over heat; the board's total thickness affects how readily heat comes through, and that is a question for the heating designer. The underfloor heating guide covers it.
Common questions
Is a thicker wear layer more durable day to day?
No. Day-to-day durability comes from the finish and the surface, oiled or lacquered, brushed or smooth, not from the depth of oak beneath them. The wear layer decides how many times the floor can be sanded, not how it wears between sandings.
Can a 3 mm wear layer be sanded at all?
Yes, with a light sanding by someone who knows it is 3 mm. The risk is a heavy sanding that goes through to the core, which cannot be undone. Tell the floor sander the wear layer thickness before they start.
Does the wear layer affect underfloor heating?
Not the compatibility: every engineered board here is listed as compatible, whatever its wear layer. The limit over heating is the floor surface temperature, and the guidance for it is quoted below.
How does engineered compare with solid for refinishing?
A solid board is oak throughout and can be sanded until the tongue is reached; a 6 mm wear layer comes close to that. The solid or engineered guide weighs the rest of the comparison.
The three thicknesses sit in the engineered oak range, and the specification on each product page says which. How hard a floor will be used, and how long it needs to last, depends on the house as much as the household. Browse by town and region.
