[1] It was largely rebuilt in 1405 after a fire, and was restored in 1854–55 by the architect James Fowler of Louth, when a vestry and a south porch were added.

[1][4] St John's is constructed in ironstone and chalk rubble, with limestone ashlar dressings.

Its plan consists of a nave with a clerestory, a north aisle, a south porch, a chancel, a vestry, and a west tower.

In the spandrels of the arch are a coat of arms, Adam and Eve and the serpent, and a Paschal Lamb.

On the south side of the chancel is a blocked 14th-century four-bay arcade which shows signs of fire damage.

In the wall of the north aisle is a 14th-century pillar piscina with a crocketted ogee head surmounted by a finial.