A Guide To Oak Flooring


( To download a printable pdf version of this guide, click here)

What Is Solid Oak Flooring?

Solid oak flooring is exactly what it says on the tin - wooden flooring where each individual board is made up of solid oak wood, milled from a single piece of timber.

Solid oak flooring profile

Solid oak floor boards are available in widths ranging from 120mm wide to 200mm+ wide. At Peak Oak, we are known for our long boards, with lengths from 2000mm to 3000mm. Our solid oak boards are 20mm thick with a grooved underside, designed to give maximum stability to the flooring.

Solid oak flooring underside

The boards are machined to give a tongue and groove structure, allowing the boards to simply slot together when being fitted. These boards can then be either glued, nailed or screwed to a sub-floor (width dependant).

Solid oak flooring groove detail

Solid oak flooring is available in a number of different grades, which dictate how your finished floor will look. The grade of flooring you choose comes down to personal preference with such a wide range of styles available. Some of these grades include: Barn, Character, Select, Classic, Prime and Quarter-sawn. Quarter-sawn oak flooring is often seen as the “creme de la creme” of solid oak flooring, with its beautiful figuring and super tight grain. Quarter-sawn is created from only a small part of a complete tree, which makes it much rarer and more costly to produce.

Solid oak flooring in the showroom


What Is 14mm Solid Oak Flooring?

Our range of 14mm Solid Oak Flooring is similar in style to our 20mm Solid Oak Flooring. Like our 20mm boards, the 14mm boards are made completely out of solid oak which has been milled from a single piece of timber.

14mm solid oak flooring groove detail

One of the key benefits of using a 14mm solid oak board compared with a 20mm solid oak board, is price - each tree can produce more 14mm boards than 20mm and so you can fit an oak floor for much less cost. An added benefit is that a 14mm floor is closer in depth to a carpet/underlay and may allow you to fit a solid oak floor without having to modify doors.

14mm solid oak flooring top surface

These 14mm solid oak floor boards are strong enough to use as a stable floor, yet thin enough to not take up too much room. Like the 20mm boards, these boards also incorporate a tongue and groove structure, to allow for easy fitting.

Currently we have the 14mm Solid Oak Flooring available in three different grades, which are: Legere, Grange and Mansion.

What Is Engineered Oak Flooring?

Although engineered wooden floors are the most common type of wood flooring globally, you may be unaware of the differences between solid wood flooring and engineered wood flooring.

Engineered wooden flooring, rather than being completely solid wood, is made up of a solid wood top layer which is bonded to multi-layered back board (usually ply wood).

Engineered oak flooring profile showing wear layer and plyboard backing

At Peak Oak, our engineered oak boards consist of a 6mm top layer of solid oak bonded to 15mm (11 layers) of Siberian birch ply. The thicker, or the higher the number of layers, the better quality the board will be. A tongue and groove is cut into the ply backboard to allow each piece to be firmly connected to the next.

Once laid, engineered oak flooring is indistinguishable from a solid oak floor. You can finish an unfinished engineered floor in exactly the same way as solid flooring, using stains, waxes or oils, depending on the desired effect. We supply some engineered flooring pre-finished too.

Engineered oak flooring boards are available in a number of different grades, which include: Character, Select, Classic, Prime and many more.

So why fit an engineered floor?

One of the main benefits of engineered oak flooring is that the boards are far more stable when exposed to changes in humidity. This means that engineered oak is better suited for use in areas such as the kitchen and bathroom or used over the top of an underfloor heating system with minimal expansion or shrinkage.


Solid Oak, 14mm Solid Oak Or Engineered Oak Flooring?

So now that you know exactly what solid oak flooring, 14mm solid oak flooring and engineered oak flooring are, the next question has to be which one is right for you?

This choice largely comes down to where the flooring is to be laid.

In areas with stable humidity, such as a living room, solid oak flooring is perfect for the job.

If you need to lose as little room height as possible, perhaps to replace carpet in rooms with a stable humidity, our range of 14mm oak flooring is probably best.

In rooms with variable humidity, such as the kitchen, or where you have fitted underfloor heating, engineered oak boards are normally a better solution.

14mm solid oak, 21mm engineered oak and 20mm solid oak flooring


Great article ....really informative

Tony Skerl February 23, 2013 at 4:21pm

Very easy to read and understand.
Thank you!

kerry knight November 24, 2016 at 1:43pm

It appears there is some contradiction.

1. It implies 20mm boards need a sub-floor, whilst 14mm boards can be used as primary.
"These boards can then be either glued, nailed or screwed to a sub-floor"
"These 14mm solid oak floor boards are strong enough to use as a primary floor"

It says engineered oak can be used in kitchens or bathrooms implying solid oak cannot but in the product description it says solid character grade can be used in any room.
"This means that engineered oak can be used in areas such as the kitchen and bathroom"
"Character grade oak boards also look great in more modern homes where they provide a durable, eco-friendly, warm floor in any room"

Ian Warhurst March 18, 2019 at 9:45am

Hi Ian,

Thanks for your comments. We have now reworded the guide to hopefully clear up any confusion.

20mm Solid Oak boards can be fitted to joists, fitted over wooden subfloors or (for boards no wider than 120mm) glued to a concrete subfloor.

Our 14mm solid oak boards are designed for laying over an existing timber subfloor/plyboard base.

Engineered oak flooring is typically more stable than solid, making it more suitable for use in areas of changeable humidity.

Hope this helps.

Peak Oak March 18, 2019 at 9:57am

I’ve seen the comments referencing boards coming with small knots and cracks unfilled. What is your recommendation as what should be used as a filler? I see you sell a resin and I have seen other sites talk of mixing resin with dust from the boards. Is this Peak Oak’s recommended method or do you advocate pre-made wood fillers?

John Petley October 21, 2019 at 12:36pm

Hi John,

Generally we would leave these knots etc. unfilled to add to the character of the oak floor or if you are worried about knots we would suggest opting for a cleaner grade of timber.

We do have the Blanchon Resin Filler available which as you suggest is mixed with the sawdust leaving a filler that tends to blend into the wood better than the likes of "putty" fillers.

Hope this helps

Peak Oak October 21, 2019 at 12:42pm

I purchased about 40 sq mtrs some 8 years ago and they still look brilliant. Best thing I ever did.

David Bate December 3, 2020 at 4:35pm

Hi We installed a lovely oak floor in a previous property using face screw and plug using a countersink. It gave a lovely old appearance when the Oslo was applied. I am now considering laying a 21mm thick 15/6 oak engineered board to the kitchen and wondered if this method is acceptable for that flooring. Subfloor will be existing floorboards which have previously been covered by 9mm marine ply. Thanks

Rab January 13, 2021 at 3:21pm

Hi Rab,

When laying an engineered oak floor, you would typically lay onto a wooden subfloor using the secret fixing method. This involves screwing or nailing through the tongue/groove of the oak board.

An alternative method of laying which is possible with engineered oak flooring is the floating method. For this method, the engineered boards are laid ontop of an underlay. The tongue/groove of these boards are then glued together using a PVA Wood Flooring Glue.

Hope this helps.

Peak Oak January 13, 2021 at 5:19pm

We have had 14mm boards from you in the past and are generally happy with them, We found on the second batch that the boards are trying to bow up at the ends (or has the appearance of doing so).
Anyway, we are thinking of redoing the front room and instead of covering with 14mm over the existing floor boards we want to rip up the original pine boards and replace with oak so we can put insulation between the joists. Are engineered solid planks ok for a primary floor like this and is the hidden nailer sufficient for fixing.

Philip Cross January 17, 2024 at 9:49am

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