See PDF --->

Standard classroom wall partition is minimum 50 STC.
(STC is measurement of resistence to sound transmission. It stands for Sound Tramnsmission Class).

The simplest solution for this is (as per PDF):

- 3.5" metal studs (usually 16" on center)
- 3.5" cavity filled with mineal wool batt insulation
- Double drywall both sides of partition
- Joints staggered, perimeter caulked
- *** Insulated partition must exted all the way up to the underside of structure (i.e. acoustic insualtion must go above drop acoustic ceiling up to the slab, to prevent sound transmission between classsrooms through the ceiling cavity).

This will provide approx 50 STC sound transmission resistence.

Resiliant channel construction can achieve 50 STC but above construction is preferred as resilent channel can have highly diminished performance if drywall screws are mistakenly driven through the channel to the stud during construction.

If a glass wall partition is required, use highest available STC partition. Use of 2 panes of differing thickness glass will increase STC rating (as each thickness of glass will negate a different frequency range).


A tyical residentail hollow-stud cavity wall is 15-35 STC.
STC ratings are for an assembly, not per-component or product.

STC RatingDescription of Performance
30Loud speech understood fairly well
35Loud speech audible but unintelligible
42Loud speech audible as a murmur
45Must strain to hear loud speech
48Loud speech audible as a murmur
50Must strain to hear loud speech


The OSM standard requires the 50STC assembly above the finished ceiling to the structural slab. However site conditions may make this impossible; In these cases the architect should notify the client (UofT/OSM) and propose and alternate assmbly above the finished ceiling in the areas where the standard partition is impractical. 2 proposed solutions have been the use of rigid and expanded foam and the use of batt ceiling insulation (above the acoustic ceiling) for 3' around the room perimeter.
OSM Classroom Design
Classroom Design Information for the University of Toronto