This thesis sets out to describe the effects of thermal bridges in Irish construction practice Thermal bridges are particular points where heat loss is accentuated relative to other parts of a building such as floors, walls and ceilings Thermal bridges are currently not regulated by the 1991 Building Regulations and their Technical Guidance Document, Part L, they are also an increasingly important part of energy consumption in buildings and therefore are important environmentally. There are two very common buildings found in Irish construction the bungalow and the semi-detached house Each building has approximately 10-15 thermal badges. These badges are identified in Chapter 2. In Chapter 3, the lash and other European Building Regulations are discussed with regard to thermal bridging. In Chapter 4, the methods of analysis of thermal badges are discussed. The European standards governing these methods are also discussed. In Chapters 5 and 6, the theory of the finite element and finite difference methods are summarised. These two methods are the methods typically used in commercial thermal analysis software. In Chapter 7, the validity of the analysis of the thermal badges and of the assumptions used in their analysis is discussed. In Chapter 8, a full analysis using several methods is performed on a thermal badge. Analyses for two thermal badges, from a bungalow and a semi-detached house, performed using a finite element program are summaased. In Chapters 9 and 10, the results obtained by the finite element analysis of the thermal badges identified m Chapter 2 are summaased and discussed (Appendix A contains the detailed results of all the thermal badging simulations). The thermal badges listed were simulated using the ANSYS finite element program to determine their thermal effect. As a percentage of total fabac heat loss, the heat loss due to thermal badging aggregates to 25% in the bungalow and 22% in the semi-detached house. The effect of thermal badges is significant and should be taken into account in thermal calculations.