Description

The Building Regulations in England and Wales impose increased performance requirements with the 2010 revision of Approved Document L: Conservation of fuel and power that takes effect in October. Compared to the 2006 Part L, the new rules demand a 25% improvement in thermal performance.

Designers following The Code for Sustainable Homes will find the thermal target for Code Level 3 matches the new 2010 Part L. Code Levels 4, 5 and 6 will be even harder to achieve. The 2010 Part L requires designers to analyse the entire fabric, with particular emphasis on cold bridging. The measure of heat loss via a cold bridge is the linear thermal transmittance (ψ-value), measured in W/mK.

This publication explains what cold bridging is, how to calculate the ψ-value and how to demonstrate compliance when using the standard details with mineral wool or rigid foam insulation. Working out the ψ-values needed to input to The Standard Assessment Procedure (SAP) can be taxing. Fortunately, software now exists to do the calculations. But even with the software, it remains a tedious process. SAP lists the situations in a typical building where cold bridging is likely to have a significant effect on overall thermal performance. TRADA Technology's Building Performance Service has identified 20 critical details that arise in timber frame construction, and has calculated the ψ-value in each instance using 'standard' details published in Timber Frame: Standard Details for Houses and Flats.

Also available: Timber frame: standard details for thermal performance. Volume 2: rigid foam insulation. This can be purchased individually, or as a pack combined with volume 1: mineral wool insulation. The pack price is £210.00 + VAT, representing a saving of £50.00 + VAT.

TRADA published a further set of 'enhanced' standard details for increased thermal performance, again for both mineral wool and rigid foam insulation. Designers will be able to select and combine details from either set to achieve regulatory requirements. These will be priced at the same level as the standard details (£130.00 + VAT for individual volumes and £210.00 + VAT for both volumes combined).

Customers can also select the option to receive the Enhanced Details when purchasing the Standard Details. This option represents a further saving of £60.00 + VAT on each volume set individually, and £120.00 + VAT on the pack price of both volumes.

The full pricing structure is set out below:

Mineral Wool Insulation
Volume 1: £130.00 + VAT (standard details); (enhanced details); £200.00 + VAT (standard & enhanced details combined)

Rigid Foam Insulation
Volume 2: £130.00 + VAT (standard details); (enhanced details); £200.00 + VAT (standard & enhanced details combined)

Both Types of Insulation
Volumes 1 & 2: £210.00 + VAT (standard details); (enhanced details); £300.00 + VAT (standard & enhanced details combined)

Please contact the TRADA Bookshop for further details on +44 (0)1494 569602/ publications@trada.co.uk