img keystobe

Understanding thermal bridging

  • 8 Sep 2017

  • Share

With a drive towards more energy efficient homes, thermal bridging is becoming more important within the industry. But what is thermal bridging?

A thermal bridge is part of the building envelope through which heat is transferred at a substantially higher rate than through the surrounding area. The heat loss at these junctions are considered independently of the U-Values of the elements.

It has been found that up to 30% of all heat loss from buildings is due to thermal bridging. Therefore, building regulations now require the heat loss through U-Values and Thermal Bridging (Psi values) to be accounted via SAP calculations. 

The two main types of thermal bridges in building are repeating and non-repeating. Repeating thermal bridges occur regularly within a typical dwelling; for example where timber studs bridge a layer of insulation in a cavity wall. These are taken into account in the ‘U-Value’ calculation.

Non-repeating thermal bridges occur at junctions between building elements and around openings, these are measured as Psi values (linear thermal heat transmittance). The Psi values are accounted for in the SAP calculation.

Non-repeat thermal bridging is measured as a Psi Value, which is a measure of linear thermal heat transmittance usually at a junction in a dwelling. A Psi value is calculated using specialist thermal modelling software, where the thermal modeller will draw the construction detail in the software package and add in the material conductivities. This sophisticated software then calculates the heat loss at the junction, subsequently producing a Psi value.

Psi values are based on standard construction details but default Psi values can be enhanced through the use of thermal modelling by a third party-accredited assessor. Improved Psi values can help eliminate the need for costly eco add-ons, such as solar panels, and are worth exploring as a means to reduce the cost of a new build whilst meeting fabric requirements, energy requirements of Part L of the building regulations and Code of sustainable homes.

Visit the Keystone Lintels website

Leave a Reply

More articles

Washroom Washroom

Camden Market gets Washroom Washroom delivery

Washroom Washroom has delivered a complete turnkey washroom refurbishment for Camden Market, one of London’s largest and most diverse markets.

Posted in Articles, Bathrooms, Bedrooms & Washrooms, Building Industry News, Case Studies, Interior Design & Construction, Interiors, Posts, Restoration & Refurbishment, Retrofit & Renovation

  • Share
Screen Shot 2018-04-20 at 11.49.41

Charcon ups the game with new innovative lightweight stairs

Charcon Construction Solutions, part of the Aggregate Industries Group, has introduced a lightweight product to its pre-cast concrete portfolio.

Posted in Articles, Building Industry News, Concrete, Cement, Admixtures, Innovations & New Products

  • Share
SFS Intec

New assembly facility for SFS following feedback

In response to market feedback, SFS has invested in a new, Leeds-based assembly facility that will offer supreme quality, colour-matched AP rivets for rainscreen cladding.

Posted in Articles, Building Industry News, Building Products & Structures, Cladding, Facility Management & Building Services, Plant, Equipment and Hire, Posts, Walls

  • Share
MRA Marketing

Marvellous MRA and brilliant Brisant scoop CIM award

MRA Marketing and Brisant Secure have bagged the 2018 Chartered Institute of Marketing (CIM) Award for Innovation – New Product/Service in April.

Posted in Access Control & Door Entry Systems, Articles, Awards, Building Associations & Institutes, Building Industry Events, Building Industry News, Posts, Security and Fire Protection

  • Share