Thermal bridges reduce the thermal resistance of the elements that form the building envelope. In addition to energy losses, a thermal bridge implies the risk of condensation and the presence of mould in winter.
The importance of design
A correct design of the building envelope and correct execution on site serve to limit the negative effect of thermal bridges, contributing to energy efficiency and healthiness of the building.
In high energy-efficiency buildings, thermal bridges are of greater importance, as the thermal transmittance of the envelope elements (both the opaque part and the openings) has been reduced to a minimum, and most of this thermal transmission, this time in the form of losses, will occur through thermal bridges and air infiltration.
Every building design has its thermal bridges. In general, we consider the thermal bridges to be those areas of the building envelope where the uniformity of the building varies, either due to a change in the thickness of the cladding, the materials used, etc. These heterogeneities lead to a reduction in the thermal resistance of the enclosure. In addition, thermal bridges are sensitive parts of buildings where surface condensations are more likely to appear, especially in winter or cold season.
The most common thermal bridges in buildings
Thermal bridges integrated in enclosures
Pillars integrated in façade envelope.
Case of insulation with sprayed polyurethane. Solving thermal bridges integrated in façade, such as pillars, is quick and simple: it is enough to extend the projection around the element, regardless of its shape.
- Control of openings and skylights.
Case of insulation with sprayed polyurethane. Encounters with chimneys and skylights. These singularities must be treated with specific spray foam projection on the meeting line of the vertical and horizontal plane before applying a general projection on the whole surface.
- Shutter boxers.
- Other integrated thermal bridges.
Thermal bridges formed by
Slab fronts on façades.
On the interior.
Case of projected polyurethane. When possible, the spray foam should be extended by 30 cm both on the upper and the lower slab in order to correct the thermal bridge created by slab fronts.
- On the outside
When projecting on the outside, the slab fronts must always be insulated.
- Roof-façade junctions:
- Roofs with parapets
Case of sprayed polyurethane foam. In roofs with parapets, the projection will be carried out first on the meeting line. The foam projection must be extended along the parapet with a gradual decrease in thickness. In case of elastomer finish, this shall be extended if possible up to the coping, or otherwise at least to a height of 10 cm higher than that of the foam.
- Roofs without parapets
- Joint façades with enclosures in contact with the ground:
Join facade with slab or sill.
Junction of façade with buried wall or screen wall.
Corners or façade junctions, depending on the position of the external environment, are subdivided into the following:
- Interior corners. Incoming corners.
- Exterior corners. Protruding corners.
- Façade-cantilever junctions. Encounters of cantilevers with facades.
Encounters of interior partition walls with facades.
Do you need help to deal with thermal bridges? Do not hesitate to contact us for more information about Synthesia Technology insulating polyurethane systems.