Accredited Details

Best Practice > Accredited Details

Accredited Construction Details (ACD’s) have been developed to assist the construction industry achieve the performance standards required to demonstrate compliance with the energy efficiency requirements (Part L) of the Building Regulations.

The details and introductory section focus on the issues of insulation continuity (minimising cold bridging) and air tightness.  They are not intended to provide any detailed guidance on other performance aspects such as vapour control, ventilation, etc which must also be considered by the design and construction team.

The details contain checklists which should be used by the designer, constructor and Building Control Body to demonstrate compliance.

The details have been grouped by generic construction type.  It is strongly recommended that the introductory section is read in conjunction with the particular set of ACD’s in order to better understand the principles underpinning the details themselves.

If you are using accredited details, you will be given some advantage in the SAP assessment, which will make it easier to reach your acquired carbon dioxide emissions target.

Accredited details specific for the Republic Of Ireland

These Acceptable Construction Details (ACDs) focus on thermal bridging and air tightness.  This guide will help appropriate persons to achieve the performance standards in the Technical Guidance Document (TGD) to Part L of the Building Regulations 2008 – Conservation of Fuel and Energy – Dwellings.

The guide is presented in 2 sections.  Section 1 discusses the general theory of insulation continuity and air tightness in construction.  Section 2, in seven separate parts, provides indicative detail drawings of thermal insulation and airtightness provisions for specific construction interfaces.

As maximum permissible U-values decrease, requiring more insulation the impact of thermal bridging and air tightness becomes more significant.

In Northern Ireland, there is a requirement for building control site visits and a site inspection regime. In the Republic of Ireland the architect signs off on the site.

Thermal imaging analysis

The air tightness of the dwelling can be confirmed via and air tightness test, however, it can be very difficult to pinpoint thermal bridges or gaps in insulation. One way of doing this is to use a thermal imaging camera, which will generate an image based on temperature of the service thus representing level of heat loss.