18mm vs 14mm vs 20mm Engineered Wood Flooring – Which Thickness is Right for You?

Introduction

One of the most common questions we hear from customers is: “What thickness of engineered wood flooring do I need?” With options ranging from 10mm to 22mm, it is easy to feel overwhelmed. The thickness you choose affects everything from durability and installation methods to underfloor heating compatibility and cost.

In this guide, we compare the most popular thicknesses — 14mm, 18mm, and 20mm — to help you make an informed decision for your project.

Quick Comparison: Engineered Wood Thicknesses

14mm Engineered Wood Flooring

Best for Bedrooms, Home Offices, and Low-Traffic Residential Areas

14mm engineered wood is a popular choice for rooms that do not experience heavy foot traffic. Its lighter weight and thinner profile make it easier to handle during installation, and it is often more budget-friendly.

Pros

• Excellent heat transfer for underfloor heating

• Lower cost per square metre

• Easier to cut and install

• Suitable for floating installations

Cons

• Limited sanding capacity, typically 1–2 times

• May feel less substantial underfoot

• Not suitable for installation over joists

• Shorter overall lifespan, usually 15–20 years

Ideal for

Guest bedrooms, home offices, spare rooms, and areas where budget is the main concern.

18mm Engineered Wood Flooring

Best for High-Traffic Areas, Family Homes, and Rooms with Underfloor Heating

The 18mm category represents the sweet spot for many UK homes. It offers substantial durability while remaining compatible with underfloor heating systems.

Pros

• Can be sanded and refinished 3–5 times with a 4–6mm wear layer

• Suitable for installation over joists, as 18mm is usually the minimum required

• Excellent durability for high-traffic areas

• Better sound and heat insulation

• Long lifespan of 25–30+ years

Cons

• Higher cost than 14mm options

• Heavier and more difficult to handle

• May require door undercutting

Ideal for

Living rooms, hallways, open-plan family areas, kitchens with precautions, and homes with underfloor heating.

20mm Engineered Wood Flooring

Best for Luxury Projects, Commercial Applications, and Period Properties

Premium 20mm engineered wood delivers the most substantial feel and longest lifespan. It often features wear layers of 5–6mm.

Pros

• Maximum sanding capacity, usually 4–6 times

• Most substantial feel underfoot

• Can be installed over wider joist spacing

• Premium appearance and longevity

• Often features traditional tongue-and-groove fitting

Cons

• Highest cost per square metre

• May be too thick for some door clearances

• Can be heavy and difficult to install

• Some 20mm products require glue-down installation

• May not suit all underfloor heating systems

Ideal for

Luxury new builds, commercial spaces, heritage properties, and projects where budget is less of a concern.

Sanding Capacity Explained

One of the most important factors when choosing thickness is how many times the floor can be sanded. Every time engineered wood floors are restored, around 1mm is removed by the sanding process, with another 1mm often allowed for factory defect differences.

Most of our 18mm engineered wood flooring features a wear layer between 4mm and 5mm, allowing the flooring to be refinished 2–4 times.

Installation Considerations by Thickness

14mm Installation

• Primarily floating installations

• Click-lok systems are common

• Requires quality underlay

• Must be installed over a flat subfloor

18mm Installation

• Floating, glue-down, or secret-nail options

• Click-lok available for DIY fitting

• Can be installed over joists with 400mm spacing

• Versatile installation methods

20mm Installation

• Often traditional tongue-and-groove requiring glue

• Can be secret-nailed over timber subfloors

• Professional installation is recommended

• Some products are suitable for floating installation

Underfloor Heating Compatibility

All thicknesses require water-based systems. Electric underfloor heating can overheat and damage boards.

Which Thickness Should You Choose?

Choose 14mm if

• You are on a tight budget

• The room has light foot traffic

• Maximum underfloor heating efficiency is your priority

• You do not plan to sand the floor in the future

Choose 18mm if

• You want the best all-round value

• The room has moderate to heavy traffic

• You have or plan to install underfloor heating

• You want a floor that can be refinished multiple times

• You are installing over joists

Choose 20mm if

• Budget is less of a concern

• You want maximum longevity and sanding capacity

• The project is commercial or luxury residential

• You prefer traditional installation methods

Conclusion

While each thickness has its place, 18mm engineered wood flooring offers the best balance of durability, performance, and value for most UK homes. It provides the reassuring solidity of a substantial floor while remaining compatible with modern features such as underfloor heating.

Browse our full range of 18mm engineered wood flooring and order free samples to find your perfect match.