Fixing classroom echo without suspended ceilings

A Victorian primary-school classroom brought from 1.15s down to 0.55s reverberation, inside BB93's refurbishment limit -- without touching the ceiling. An illustrative worked example: an 8 x 6.5 x 3.6m Victorian classroom (187m3) with a baseline reverberation time of 1.15 seconds -- well outside BB93 Table 6's refurbishment limits (0.8s primary, 1.0s secondary). Treated with roughly 26m2 of wall panels and 52m2 of carpet tile (which also helps with footfall noise); curtains were costed but not used. Result: 0.55 seconds, comfortably inside the binding limit -- a design-stage Sabine/Eyring prediction, not a substitute for a measured survey to BS EN ISO 3382-2.