Following figures show the commonly used structural terms in energy efficiency reports.

Typical dimensions of timber frame

Timber stud or timber joist is most commonly used to create insulation gap in the wall and ceiling. Theses are typically 90mm deep with 45mm thick studs depending on load and spacing — usually 600mm. Noggins (spacers) are inserted between studs to provide lateral support. Additional noggin rows are often required for taller walls. Top and bottom plates are typically 90x45mm and can be double thickness depending on the load (e.g. first floor, tiled roof, long truss spans) or the spacing of the supporting floor members. These are typical figures that we use to consider thermal bridge effect in commercial buildings.

Purlin vs Rafter

Purlins are along the wall and rafters are perpendicular to the wall. If you increase the spacing between the rafters, purlin depth will increase. Purlins center to center spacing is around 1.2m.

Studs are vertically installed columns (every 600mm) or insulation gap makers in the wall.