The buildings of the Abbey were laid out in 1095 by Eudo Dapifer and the first of them completed in 1115. The cloister and domestic buildings lay north of the church, as a small hill occupied the land to the south. The abbey was burnt down in 1133 and all the workshops, which were originally on the north side were rebuilt to the south side of the church' . The church was rebuilt on a cruciform plan, with a massive central tower and an elaborate west front flanked by south-west and north-west towers, possibly round. Late 12th century capitals, perhaps from the internal jambs of a window or from blind arcading, found near the abbey site, may have been from its church or chapter house. The abbey was dissolved in 1538. Lead from the church roof had been removed in 1552 so it was apparently a ruin by this time.<1><4>

Remains shown by Cutt's Map in Abbey Gardens, thought by Rex Hull to be the domestic wings of the Abbey.<2>

The only known drawing of St John's Abbey is held by the British Library, a copy is held in the Museum Social History Files. The drawing belongs to the Cotton manuscript, Nero D. VIII, a collection of pieces of different dates that were bound together by 1631 at the latest.<3>

See also MCC441 for the Abbey's precinct wall.

Further investigation of the Abbey precinct occurred during the redevelopment of Area B1b (previously known as Flagstaff House, now known as Arena Place) in 2015-17 (see ECC2911, ECC2912 and ECC2913).<5> Approximately 16.5m of surviving in situ foundation from the precinct wall of St John's Abbey was revealed in excavation Area A and during monitoring around Block A, constituting part of the southern east/west wall. The foundation was 0.8m wide and was made of septaria, greensand stone and reused Roman ceramic building material set into a lime-mortar, similar to that seen in 1972 when part of the standing wall was demolished (CAR 9, 219). Between Area A and Block A, a short stretch (c.9m) of precinct wall survives built into the southern wall of Block F (a garrison wagon shed dated to the late 19th century). In 2016, as part of the current redevelopment, the wall was surveyed and conserved. The exact alignment of the precinct wall in the southwest corner remains uncertain. In terms of associated buuildings and strcutures within the abbey precinct, in Area C, a structural feature was encountered in the base of an area of quarry pitting associated with postholes, a gully and layers of compacted clay. A lace tag compressed into the top of a clay layer shows that it was in use by c.1375 to 1550/75. The remains of a medieval clay oven were also found in a service trench to the east of Block A. The oven was probably dome-shaped and sub-divided into two compartments. No dating evidence was recovered but it had been built against the inside of the precinct wall and must post-date the construction of the wall. Two small sections of wall foundation were found in monitoring trenches in the north/south access road and to the north of Block A. Of probable medieval date they could represent the remains of internal structures but neither could be properly excavated or explored. The current project also revealed a further three lime kilns around the area of the White Building and Block O (in addition to three lime kilns already recorded within St John's Abbey precinct). All six of the lime kilns now known from St John's Abbey precinct were round features with scorched edges measuring between 4-7.5m in diameter with two recorded at 1.7m and 2.15m deep. The quarry pits in Area C are likely to be contemporary with the lime kilns as they would have provided sand and gravel for construction. The remains of the possible temporary structure/workshop in the base of the pits would provide further evidence that this was a working area of the precinct. It is possible that two parallel ditches in the White Building continue northwards in Area C and towards the abbey gatehouse forming a trackway through the precinct. Most of the medieval ditches are concentrated to the west of this possible trackway and may have created defined plots; dating evidence suggested that most of the ditches had either been backfilled or were not being maintained by the 14th/15th century.