Building Physics Applications

Evaluating building details through performance

A junction between a window and a wall can affect both heat loss and internal surface temperature. Our building physics work assesses such decisions through heat, moisture and indoor conditions. By comparing façade, roof and junction alternatives, we explain how material and detail choices relate to building use. This helps the design team understand how junctions affect building behaviour.

The work can compare alternatives for a new building or investigate a specific performance issue in an existing property. We clarify the question with the client, architect and engineering teams. Envelope choices may be the priority during design, while junction details and material changes may become the focus during construction.

Thermal assessments cover heat transfer through building elements, thermal bridges, surface temperatures and envelope alternatives. We consider each detail's position in the building and its relationship with adjacent elements, alongside individual material properties. This helps the design team understand the conditions under which alternatives offer benefits and where further attention is needed.

Moisture assessments consider the assembly, indoor and outdoor conditions, and patterns of use. Investigation of condensation and moisture risks can inform layer arrangements and junction decisions. Depending on the project, we can also include solar control, daylight, air movement and thermal comfort. Considering the relationship between these topics supports decisions that address more than a single performance indicator.

We first define the performance objective, review available drawings and details, and identify the required inputs. We agree conditions of use and assumptions with the project team. Alternatives are then assessed on a common basis. We explain differences in the results in relation to the relevant material or design change.

The assessment report presents inputs, methods and the conditions under which the findings apply. We identify how recommendations can inform drawings, which details require development and where further information is needed. Reviewing the effect of subsequent design changes on the assessment can also be planned within the agreed scope.

We select methods according to the physical issue being investigated. For example, ISO 13788 calculation methods for surface humidity and condensation risks in building elements provide an assessment framework under defined assumptions. ASHRAE 55 — Thermal Environmental Conditions for Human Occupancy is a relevant reference for thermal comfort. In Türkiye, TS 825 — Binalarda Isı Yalıtım Kuralları, the Turkish standard for thermal insulation in buildings, also provides a relevant technical framework. The method is selected for the detail and performance question under review.

Deliverables include a building physics report, comparisons of alternatives and risks, and recommendations for envelope assemblies, materials and junction details. We present findings with the team's decision sequence in mind. For the relationship between façade exposure and indoor illumination, see our daylight and solar radiation service; for comparing envelope decisions, see our optimisation service.