
TYPES OF THERMAL BRIDGES Thermal bridges can be classified into three main types: REPEATING Repeating thermal bridges usually follow a regular pattern and are evenly distributed over an area of the thermal envelope. Typical examples include: Repeating thermal bridges
Mortar joints in insulated blockwork and stainless steel wall ties are common examples of repeating thermal bridges Repeating thermal bridges can have a significant effect on heat loss, and are required to be taken into account in the calculation of U values (see Calculating Thermal Bridges). NONREPEATING Nonrepeating thermal bridges are intermittent and occur at a specific point in the construction. They are often caused by discontinuities in the thermal envelope. These discontinuities may be a result of the construction method used or may be due to changes in materials over the thermal envelope. They commonly occur around openings and other instances where materials of different thermal conductivities form part of the external envelope. Typical examples include: Nonrepeating thermal bridges
Box lintel results in a nonrepeating thermal bridge through the external wall at the window head
Use of top hat lintels results in a number of nonrepeating thermal bridges at the window head GEOMETRICAL Geometrical thermal bridges, as the name suggests, are a result of the geometry (or shape) of the thermal envelope. They can be 2dimensional (where 2 planes intersect) or 3dimensional (where 3 or more planes intersect). The occurrence of geometric thermal bridging is likely to increase the more complex the building geometry. Typical examples include:

