Quote

At Hilsea, the changes since the Peace have been very extensive; the wooden Barracks, capable of accommodating many thousand men, and erected at the desire of the Duke of Cumberland, have been gradually removed, excepting the Hospital and a small brick building. It now appears as an extensive airing-ground, round which has been planted a belt of trees, and the fences &c. renovated; while at Portsbridge, the only entrance of the land side, the ancient gavel-fronted Guard-house has yielded to a modern Grecian erection, of much taste.

— Slight, Henry and Julian (1828) Chronicles of Portsmouth. Lupton Relfe, 13, Cornhill, London source

Question

If the barracks were wooden when torn down in the first quarter of the 19th Century, how come they’re salt-water brick in 1763? Am I missing a rebuild?