Thermal bridges create cold spots and can lead to condensation, mold and energy bills that are higher than they should be. They can also thwart the achievement of energy standards and recommendations.
Localized higher heat flows at thermal bridging points need to be accounted for when calculating the assembly R-values/U-factors. This requires detailed construction documentation and finite element calculation (e.g.
1. Loss of conditioned air
Whenever you have a less-insulative material bridging an insulated space, unwanted heat loss (or gain) can occur. In winter, this will cause the conditioned air in your home to escape; in summer, it will lead to higher cooling bills. This unwanted transfer of energy is what’s known as a thermal bridge, and it can be extremely expensive to deal with.
It’s essential that builders, energy auditors and enclosure professionals account for thermal bridging when designing and installing insulation. A thorough thermal modeling analysis should be used to identify and eliminate these energy leaks, as well as any other potential weaknesses in the building envelope.
In addition to allowing unwanted heat to travel through a structure, thermal bridging can also encourage condensation. This is because warm air often mingles with cooler surfaces such as drywall and framing, which can create the ideal conditions for moisture to form. Constant condensation can result in rot, mold growth and other structural damage.
For example, a 2×6 wall insulated with fiberglass batts may have an R-value of 19; however, a steel stud will bridge the insulation and allow for uncontrolled heat flow. This can lower the overall R-value of your entire wall, and it will reduce your comfort levels and energy efficiency as a result. Taking the time to eliminate all thermal bridges in your home will make sure that your insulation is working at its peak performance and efficiency.
2. Condensation
In homes and commercial buildings, condensation is a problem that can affect indoor air quality, lead to the growth of mold and cause damage to insulation materials. Condensation often occurs when heat travels over more conductive materials than the surrounding insulation, such as wood studs. These studs in conventional framed walls act like thermal highways, transporting heat to the outdoors. This can reduce the effectiveness of the entire wall assembly.
Thermal bridges can significantly reduce the effective R-value of a building, which undermines the energy efficiency work that we’ve done to insulate our homes and buildings. They can also create cold spots in a house, which can be uncomfortable for occupants.
Identifying thermal bridges is important for both new construction and retrofits. It’s the responsibility of architects, engineers, and enclosure professionals to ensure that these problem areas are adequately insulated. It’s equally important for builders and tradespeople to be careful when constructing and installing building elements that will act as thermal bridges.
In order to minimize thermal bridging, the choice of material needs to be taken into account. This includes the type of insulator, its thickness and the thickness of any covering materials such as siding or paint. A good rule of thumb is that any framed element in a wall, roof, or foundation should be covered with at least 1 inch (2.5 cm) of insulation to avoid forming thermal bridging.
3. Moisture accumulation
Many homeowners rely on insulation to keep their homes warm in the winter and cool in the summer. Adding insulation to your walls helps to prevent unwanted air infiltration, moisture intrusion, and mold growth. However, if you have thermal bridges present in your home’s structure, your energy savings could be compromised by a lack of efficient heating and cooling.
These areas of unobstructed heat flow bypass your insulated sheathing and insulation and transfer more heat into the framing and wall system. As a result, your home’s energy efficiency may be compromised and you will spend more money on maintaining the desired temperature.
Moisture accumulation from condensation can also lead to mold growth, wood rot, mildew, and other structural damage. In addition, it can cause deterioration of the building envelope and degrade the insulating value of your sheathing and air barriers.
A home’s energy efficiency is largely dependent on the quality of the insulation and the airtightness of the building envelope. A high-performance insulated sheathing such as GreenGuard extruded polystyrene will help you avoid the detrimental effects of thermal bridging and maintain your home’s performance standards. This durable, closed-cell insulation provides a barrier that resists air and moisture to minimize energy loss due to thermal bridging and moisture transfer. Contact us today to learn more about Kingspan GreenGuard and our other insulated sheathing products.
4. Damage
Thermal bridges can have a significant impact on the health and performance of your home or building. They can cause condensation or other moisture problems that can affect indoor air quality and lead to mould fungus and other damaging effects. They can also cause damage to the air barrier and insulation materials by causing them to degrade or become waterlogged.
During hot weather, thermal bridges allow heat to bypass the insulation layer and reach surfaces where it can cause condensation or other moisture problems. This can occur on the interior surface of a wall or in window frames, which can also lead to structural damage.
These bridges can also reduce a building’s effective R-value. For example, a 2×6 wall with mineral fiber insulation has an R-value of about 19. If a steel stud is present, the heat from the sun can easily pass through the steel and reach the interior surface of the wall where condensation may form. This can decrease the wall’s overall R-value to R-11 or lower.
To minimize the negative effects of thermal bridging, it is important to use continuous insulation materials such as fiberglass or spray foam that prevent and/or reduce energy transfer by slowing the movement of thermal energy between conductive materials. A thermal break is a material of low conductivity that is placed within or around a larger, insulated assembly to reduce the flow of thermal energy between those conductive materials.