All you need for thermal performance

We’ve analysed the changes to Approved Document L 2021, breaking them down into easy-to-digest information for Volume 1: dwellings and Volume 2: buildings other than dwellings, and giving you a side-by-side comparison versus the 2013 edition.

You’ll also find required u-values at-a-glance, whether you’re working on a wall or warm roof, and a link to our u-value calculator to work out the required thermal performance for your individual project.

Part L Guide

Insulation specification – don’t look any further 

Easy and interactive, use our Approved Document L guide to navigate to the applications you need and find suggested substrate constructions to help meet or exceed the new thermal regulations.

We’ve also advised how to use ROCKWOOL insulation alongside other commonly specified materials to help achieve the updated demands.

Part L Guide

Download the ROCKWOOL guide to Approved Document L 2021

Our guide to Approved Document L gives you everything you need to address the new thermal regulations with confidence.

Part L Guide