A Victorian classroom, brought inside BB93
Education · BB93 Table 6 refurbishment limit: 0.8 s
Illustrative worked example. This is a realistic brief run through Echo using the same method a real report uses — not an account of a named past client. See every case study for more, including which of these are real, permissioned projects as they're added.
The brief
A local-authority estates team asked for options on a two-form-entry Victorian primary school where the SENCO had flagged that pupils with mild hearing loss, and several EAL pupils, were consistently seated at the back and consistently behind. Teaching staff were also raising voice-strain complaints by half-term.
General teaching space, ground floor
8 × 6.5 × 3.6 m, about 187 m³ — painted lath-and-plaster walls, sealed timber floor, exposed plaster ceiling with original cornicing.
High Victorian ceilings and hard plaster on every surface put the room at roughly 1.15 seconds — well outside BB93's limit for a general teaching space, and consistent with the pattern reported: fine near the whiteboard, lost by the third row back.
The standard, and the target
BB93 Table 6 sets an upper limit for a general teaching space as a mid-frequency average (Tmf): 0.6 s for a primary new build, 0.8 s for a primary refurbishment, 0.8 s and 1.0 s for secondary new build and refurbishment. This room is a refurbishment, so 0.8 s is the applicable figure — a ceiling, not a target range.
The constraint
The building is not listed, but the conservation officer's condition on the wider refurbishment ruled out concealing or covering the cornicing, which took a suspended ceiling — the usual fastest route in a room this shape — off the table before the brief even started.
The decision
With the ceiling constrained, the fix had to come from the walls and the floor: Class-A panels direct-fixed to a band below the cornicing line, sized to stay clear of it entirely, plus replacing the sealed timber floor with full carpet tile — which also addressed a separate footfall-noise complaint from the classroom below.
Every route considered, vendor-neutral — we don't sell any of it.
- Wall panels below the cornicing lineabout 26 m²
Sized and positioned to clear the cornicing by a margin, not to the edge of it.
- Full carpet tile in place of sealed timberabout 52 m²
Doubled up as the fix for the footfall complaint from the room below.
- Heavy curtains at the sash windowsabout 14 m²
Considered and costed, but not needed once the panels and floor were in — kept as the reserve option for the noisiest of the four classrooms in this style.
The outcome
Panels and floor together brought the room to roughly 0.55 seconds — comfortably inside the 0.8-second refurbishment limit, and inside the 0.6-second new-build figure as well, reached without touching a single run of cornicing.
Indicative figures for this example, from the same method a real report uses. Not a measured survey and not a compliance certificate — where one is required, that's a survey to BS EN ISO 3382-2.
Now do it for your room.
Four questions, sixty seconds. Free to see whether you have a problem.
Check my room →Questions people ask
Why not just add a suspended ceiling?
It's usually the fastest route in a room this shape, but it was ruled out here by the conservation condition on the cornicing — which is exactly the kind of constraint a vendor-neutral set of options is for: when the obvious answer is off the table, you need the other four.
Does this count as BB93 sign-off?
No — this is an indicative design-stage prediction using the same method the standard is written around, not a measured survey. Where BB93 compliance has to be formally demonstrated, that's a measured survey to BS EN ISO 3382-2.
Would every Victorian classroom need the same fix?
No. This one couldn't touch the ceiling; a different building with no conservation constraint would very likely fix faster and cheaper with a suspended ceiling instead. That's why the brief and the constraints get worked through before the routes, not after.