WORKED EXAMPLES

A modern insulated box lintel in a timber-frame wall, drawn in CAD and calculated in Psiclops exactly as you would calculate your own. The detail depends on a second model: the insulated I-joist bay above it is a 2D assembly in its own right, solved separately for an equivalent conductivity and then referenced as a material — both appear below, as they would in a real report. SAP Table K1 assigns this junction type (E2) a default ψ-value of 1.000 W/(m·K) unless a bespoke calculation is provided; the calculated value is around 96% better than that default.

An external corner in the same timber-frame construction, and a good illustration of why a corner is worth modelling rather than defaulting: the two flanking walls each reach the same U-value, and the corner itself adds very little. It uses the same I-joist bay assembly as the box lintel, and carries a 25mm cavity that turns the corner — a shape whose real thickness matters, and which Psiclops measures rather than infers from a bounding box. Against SAP Table K1's E16 default of 0.180 W/(m·K), the calculated value is around 78% better.

A real, published BR 497 worked example: a steel box lintel with a perforated steel base-plate, bridging the cavity above an opening in a standard UK masonry cavity wall. Modelled here from BR 497's own published construction, dimensions, and boundary conditions (Figures B3a/B3b/B3c, Tables B3a/B3b), using Psiclops's own FEM engine — the computed ψ-value and fRsi below can be checked directly against BR 497's own declared values for this exact example.