Paying extra for a 6mm oak top layer puts your money in the wrong place. Here’s why, with the numbers to back it up.
“I want the 6mm top layer, so it lasts.” We hear it a lot in the showroom, and we get it. Thicker sounds better. More wood, more sanding, more years. Surely?
But when you look at how floors are actually made, fitted and looked after, the extra millimetres rarely earn their keep. Most of the time they’re oak you pay for and never use.
What you actually need: 14–15mm
Most of the floors we sell at Kite are engineered boards, 14 or 15mm thick. That’s typically a 3.5–4mm oak top layer bonded to a plywood base.
These floors sit on top of a structural subfloor. They’re cosmetic, not structural, and that changes everything about how thick they need to be.
Even the British Standard for fitting wood floors (BS 8201) treats 14–15mm as the norm for multi-layer boards laid over a base. Unless you genuinely need a structural floor, which is pretty niche these days, this is all the floor you’ll ever need.
Myth #1: “I’ll need to sand it loads”
This is the argument that gets trotted out most. It doesn’t stand up to scrutiny.
One of the most trustworthy sources we know, the German parquet industry, expects a floor to be sanded twice in 50 years, taking off 0.7mm each time. Those figures come from the Verband der Deutschen Parkettindustrie’s environmental product declaration for multi-layer parquet, which models how a floor is used and looked after over its life.
The rest of the time? It assumes you re-oil the floor every five years. No sander required.
That matches what we see on real jobs. With a good-quality oil or lacquer, you’re unlikely to need a full sand more than a couple of times in your lifetime, unless you want to change the colour. Floors can be cleaned, re-oiled and even re-stained without going anywhere near a sander.
Do the maths
Two sands at 0.7mm is 1.4mm of oak in 50 years. Here’s what that leaves behind:
| Top layer | Sanded off in 50 years | Never touched |
|---|---|---|
| 4mm | 1.4mm | 2.6mm |
| 6mm | 1.4mm | 4.6mm |
A 4mm top layer already has plenty in reserve. Go to 6mm and you’re paying for 4.6mm of oak that will outlive you, untouched.
Myth #2: “Thicker is more stable”
Remember, these aren’t structural floors. Glue a 15mm floor to a sound subfloor and it isn’t going anywhere.
The British Standard only asks for boards of 18mm or more when they span joists or battens, where the board itself is doing a structural job. That’s a different situation from an engineered board bonded to a solid base.
On a sound subfloor, the extra 5mm just sits there.
Got underfloor heating? More wood, slower heat
Wood is a natural insulator. The thicker the board, the more it slows heat getting from your pipes into your room.
BS 8201 says your heating engineer needs to know the floor’s thickness so they can allow for it in their calculations. Warmup, one of the biggest UK underfloor heating brands, recommends wood floors no thicker than 18mm, because anything thicker hinders the system’s performance.
A 15/4mm engineered board sits comfortably under that. A 20/6mm “premium” board goes over it.
The character problem
If you’ve chosen a floor for its texture and its oil (a deep brush, a smoked tone, a bespoke finish), you’re never going to sand it. Sanding takes off everything that makes it special.
So on the floors people fall in love with, those extra millimetres are there for a job you’ll never want done.
Where your money should go
Every floor has a price, and every price is made up of inputs. To hit a budget, you can spend on the raw material or on the finish that protects it.
So you can decide to spend your budget on:
- A. A thick oak top layer you’ll never use, or
- B. Oils that stop the damage in the first place.
We’d pick the oil every time. Upgrading the finish is a far more efficient way to keep a floor looking good for decades.
The Kite view on wood floors
- A 3.5–4mm oak top layer
- 14–15mm total thickness
- The best oil you can afford
Floors last longer than most marriages, so it really pays to do your homework. Want to see (and feel) the difference? Pop into our showroom at 5 Hackney Road, Shoreditch, and we’ll talk you through it.
Sources
- VDP EPD Mehrschichtparkett, Verband der Deutschen Parkettindustrie, EPD-VDP-20210112-IBG1-DE (IBU-verified, valid to February 2027)
- BS 8201, Code of practice for installation of flooring of wood and wood-based panels, clauses 4.7, 15.5.1 and 27.4.4 (BSI)
- Underfloor Heating for Wooden Floors, Warmup
