St Andrew's is a flint church with a nave, S aisle, chancel and W tower. In fact the present S aisle is the original nave, and its smart W front, consisting of a doorway with a triple arch above, remains inside the early 14thc. W tower. A scar on the E wall of the tower indicates that the nave was originally taller and more steeply roofed. The 12thc. S doorway also remains in situ. An aisle was added to the N of the original nave in the 13thc., with an arcade of five bays, and was apparently widened, making it much wider than the original nave, in the later 14thc. The N nave doorway dates from this period. At this time the original chancel was abandoned and a new one attached to the N aisle. Signs of the original chancel arch remain on the exterior E wall of the present S aisle. A datestone (JW 1884) on this wall presumably refers to a restoration. Romanesque sculpture is found on the W and S doorways and the W window.

Westhall does not appear in the Domesday Survey. By 1229 the manor was held by Hubert de Burgh, who was granted the right to hold there the market previously held at Serton.

Hundred River Benefice, i.e.: Willingham and Sotterley, Shadingfield, Ellough and Weston, Westhall, Brampton and Stoven.

The two doorways and the W window belong to the same campaign, which includes relatively early motifs (chip-carving, cushion capitals), but which must be datedc.1140 on the evidence of the multi-fluted capitals and the chevron ornament. The pseudo-beakhead human and beast heads towards the apex of the fourth order of the W doorway were not carved from anything like the plain tapered bridges that make up the rest of the arch. They are much too broad for this, especially towards the intrados. This to counter the popular notion that the doorway is unfinished, and that the plain 'beaker' voussoirs are roughed out ready for carving with similar heads. The same workshop was active at Wissett, where similar pseudo-beakhead and pseudo-beaker work and triple fluted capitals are found on the S doorway. Related, slightly earlier work is found at Herringfleet.