Publication of Approved Document L (2026) Volumes 1 and 2, and Approved Document F, Ventilation, Volume 1 (WGC 006/2026)

Circular number: WGC 006/2026

Date issued: 7 April 2026

Status: For information

Title: Publication of Approved Document L (2026) Volumes 1 and 2, and Approved Document F, Ventilation, Volume 1

Issued by: Paul Keepins, Building Standards Technical Manager

Addressed to: 

Local Authority Chief Executives
Welsh Local Government Association 
Construction Industry Council
Competent Persons Forum

Please forward to:

Local Authority Building Control Officers
Members of the Senedd

Summary: 

This is a circular letter to announce the publication of a new Approved Document L 2026 (Conservation of fuel and power and the minimisation of greenhouse gas emissions) Volumes 1 and 2, and Approved Document F, Ventilation, Volume 1. 

For further information contact:

Building Regulations Team
Welsh Government Offices
Rhydycar
Merthyr Tydfil
CF48 1UZ 

Direct line: 0300 060 4400
E-mail: enquiries.brconstruction@gov.wales
Website: building and planning 

1. I am directed by the Welsh Ministers to draw your attention to the publication of Approved Document L 2026 (Conservation of fuel and power and the minimisation of greenhouse gas emissions) Volumes 1 (Dwellings) and 2 (Buildings other than dwellings). In addition, Approved Document F, Ventilation, Volume 1 (Dwellings). 
    
2. In accordance with section 14(7) of the Building Act 1984, the Building etc. (Amendment) (Wales) Regulations 2026 were made after consultation with the Building Regulations Advisory Committee for Wales. 
    
3. The purpose of this Circular is to draw attention to the publication of Approved Document L 2026 (Conservation of fuel and power and the minimisation of greenhouse gas emissions) Volumes 1 and 2, and Approved Document F, Ventilation, Volume 1.
    
4. This circular does not give advice on the technical requirements in the Building Regulations 2010 as these are matters covered by Approved Documents.

5. The Approved Documents apply only to buildings and building work in Wales.

6. Welsh Ministers have approved new statutory guidance to support compliance with the Building etc. (Amendment) (Wales) Regulations 2026 (please see circular WGC 003/2026)  and Part L in Schedule 1 to the Building Regulations. Annex A to this Circular gives the Notice of Approval for the new Approved Document L Volumes 1 and 2, and Approved Document F, Ventilation, Volume 1. These approved documents are subject to the transitional provisions. 
    
7. Annex B to this Circular give the Notice of Withdrawal of previous editions of the Approved Documents, subject to the transitional provisions.
    
8. The approved documents are available at: Building regulations: approved documents

9. The new approved documents do not apply where building work on an individual building is to be regarded as commenced before 4 March 2027 in accordance with any relevant notification provision, or a relevant notification provision has been complied with in relation to proposed building work on an individual building before 4 March 2027 and the building work is to be regarded as commenced before the period ending on 3 March 2028.
    
10. In some cases, applications will be in respect of a number of buildings on a site, for example a number of houses. In such cases, it is only those individual buildings for which work is commenced which can take advantage of the transitional provisions.

Enquiries

Any enquiries on this Circular Letter should be addressed to: 

Mark Tambini
Building Regulations
Welsh Government
Rhydycar
Merthyr Tydfil
CF48 1UZ 

E mail: enquiries.brconstruction@gov.wales 

Yours faithfully,

Mark Tambini
Head of Building Regulations Policy

Notice of approval of revision of documents giving practical guidance with respect to the requirements of the Building Regulations 2010

The Welsh Ministers give notice under section 6 of the Building Act 1984 that, in the exercise of their powers under section 6, they have approved amendments to the Approved Documents listed below for the purposes of giving practical guidance with respect to the specified requirements of the Building Regulations 2010 (as amended) in Wales only.

The approval takes effect on 4 March 2027 except in respect of work on individual buildings for which a building notice or initial notice has been given or full plans deposited before that date and provided work commences before the period ending on 3 March 2028. 

Notice of withdrawal of documents giving practical guidance with respect to the requirements of the Building Regulations 2010

The Welsh Ministers give notice under section 6 of the Building Act 1984 that, in the exercise of the powers under section 6 they have withdrawn approval of the documents listed below for the purposes of giving practical guidance with respect to the specified requirements of the Building Regulations 2010. 

The withdrawal of approval takes effect on 4 March 2027 except in respect of work on individual buildings for which a building notice or initial notice has been given or full plans deposited before that date and provided work commences before the period ending on 3 March 2028.