Between 1929 and 1936 the appearance of the station changed dramatically and most of the original wooden 1917/1918 hangars, barrack blocks and offices were demolished and replaced with substantial brick structures. The seven original hangars were replaced by two new ones, although a planned third hangar was first delayed and eventually never built. Most of the domestic barrack blocks, officers' mess, station headquarters, squadron offices and married quarters built at this time still stand and remain in use. The No. 12 Group RAF Lima Sector Operations bunker, now the station museum, was constructed at a cost in 1936 of £5,000.