A thermal bridge, also knows as a heat bridge or a cold bridge, is the term used to describe areas within a building envelope where heat can flow through easily via conductive materials, bypassing any insulation materials. These occur when a component with high thermal conductivity disrupts the continuous insulation and creates a pathway for heat / energy transfer. These bridges provide a path of least resistance for heat transfer, resulting in heat loss or gain in these areas, alongside reduced energy efficiency and creating potential condensation issues.
When determining a building or structures overall energy efficiency, thermal bridging plays a vital part as even with some of the most efficient solutions on the market, these can be rendered almost redundant if significant thermal bridges are present. Let’s take a closer look at the effective strategies to mitigate the effects in order to reduce energy bills and the impact on the environment.
Examples of thermal bridging
There are several different factors that can contribute towards a thermal bridge occurring. Some of the most common causes include structural elements such as concrete slabs and steel beams that conduct heat past any insulation. Other examples include window frames, parapet, brick shelf angles, balconies and connections that link or connect different building components and materials.
Differences in thermal conductivity
Common building materials have different levels of conductivity, so some are much higher than others. This means they create a path of least resistance. When these materials connect to other elements, they can create a literal bridge across the insulation layer, they can facilitate the flow of heat either into or out of the building envelope. Examples include:
• Structural connections – concrete slabs, steel beams and metal studs
• Door and window frames made of metal which can create localised areas of heat transfer, compromising the effectiveness of any insulation
• Building component connections such as walls and roofs
Fixings and fastening
Even the smallest elements that may seem minor in the grand scheme of a construction project can contribute towards creating a thermal bridge within the building envelope if they’re not correctly or properly insulated. Examples include:
• Fastenings and brackets, including any screws and nails which can create areas of localised heat transfer (these small elements can conduct heat more easily)
• Switches and electrical outlets which can allow heat to bypass the insulation, leading to the energy loss and potential cold spots
• Cantilevers and balconies which extend further beyond the building envelope can act as conduits for heat transfer
Why is it so important to combat thermal bridges?
A thermal bridge can have a detrimental impact on the overall efficiency of a building’s energy performance. Addressing where thermal bridges occur is an essential step towards minimising energy loss and ensuring optimal thermal performance.
A structure with effective insulation but no thermal breaks to combat the thermal bridges can experience up to *60% higher levels of heat loss compared to a building with proper thermal bridging mitigation (*Morrison Hershfield)
Addressing the impact, several energy efficiency standards now include guidelines that recognise thermal bridging as a key factor in contributing towards efficient buildings.
Through proper insulation techniques, design and attention-to-detail during the construction process, the negative effects of thermal bridging can be significantly minimised.
Allowing heat to bypass insulation and creating areas of localised energy transfer means the overall heat loss or gain within a building is compromised. This results in higher heating and cooling loads, leading to increased energy consumption, consequently producing higher utility bills.
When heat is allowed to enter or escape a building envelope through thermal bridges, it creates uncomfortable spaces for occupants and visitors. Cold areas near thermal bridges can cause drafts and uneven, unpredictable temperatures, so addressing these areas can help to maintain a consistent and more comfortable indoor environment.
Thermal bridges can also contribute towards moisture issues inside a building. When any warm moist air encounters a cold surface caused by a thermal bridge, condensation can appear on interior walls and ceilings. This condensation can lead to overall moisture accumulation, encouraging the growth of mould and potentially triggering health issues with occupants and visitors, as well as the overall structural integrity of the building. To prevent moisture-related issues and ensure a healthier interior environment, thermal breaks can combat thermal bridges where these energy transfers occur.
The temperature fluctuations caused by thermal bridges can impact the long-term durability of a building. They can produce many issues that potentially reduce the lifespan of the budling materials within the construction. Reducing or eradicating thermal bridges means the overall durability and longevity of a building can be improved.
Energy efficiency standards and building codes are more frequently recognising the importance of thermal bridging and how to address them before they can create issues. Many building codes and certifications require the consideration and mitigation of thermal bridging within the original designs. Complying with the regulations not only improves the efficiency of buildings, but also facilities compliance with sustainable building practices.
Strategies to combat thermal bridges
There’s a number of ways to mitigate thermal bridges. Selecting the appropriate insulation materials and installation techniques is crucial. To minimise heat transfer as much as possible, the continuation of insulation across building components and connections is essential to minimise any transfer of energy. In addition, Armatherm’s innovative insulation materials can be used within structural connections to interrupt the heat flow and create a much more efficient structure.
Find out more about thermal breaks in our online course.
Advancements in technology
As the industry advances and building design and construction practices evolve to introduce innovative techniques and technologies to tackle thermal bridges. These include the use of high-performance, insulation materials, that can bear structural loads and address thermal bridging in difficult areas that are tricky to isolate. Additionally, thermally broken window frames, improved overall building envelope design, and application of thermal modelling tools can optimise energy performance.
Overall, understanding thermal bridges is an imperative step as the industry moves towards a greener, brighter future. Understanding their cause, impact and prevention strategies is essential for engineers, architects and specifiers to create sustainable and energy efficient structures. By addressing thermal bridging, we can reduce the amount of energy consumption and improve the overall thermal comfort of a building.
To find out more about Armatherm’s innovative thermal bridging soltuions, please contact our dedicated team via the contact us page on the website.
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