Email #76a - Architect Explains Rm. 202

In response to my email #76  “Old Noisy Room 202," Becca Cavell of Thomas Hacker Architects offers more details about the acoustic & thermal design of Rm. 202 in Architecture Hall. Her reply is below.

Also, the photo shown here of acoustic insulation on the inner (west) wall of Room 202 was added later for this website. There was no added insulation on the east wall, as shown in #76

John Stamets
Mar. 4, 2007
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John,

I am part of the architectural team for the project and wanted to point out a couple of issues regarding acoustical control and thermal comfort in this room.

Acoustical Engineering is a bit of an art, but in any room there is always a weak link which governs acoustical performance.  In this case, as in most exterior walls, the weak link is the windows.  In the "old" building the windows were single pane and poorly sealed.  In the "new" building the windows are thermally broken / insulated and the perimeters will be sealed.  So, the acoustical performance will be much improved as the windows are much improved.  However, the windows remain the weak link and so no amount of acoustical insulation in the exterior walls will help.

And yes, there are no plans to insulate the walls.  In fact, the building has massive masonry walls and while this is not how we build new projects in the C21 we are actually using that thermal mass to the benefit of the building, as a thermal store.

The old moisture problems in this room were due to failed terracotta units which have (hopefully) been fixed.  We actually peaked inside these units before construction began, using a boroscope, and slugs were living inside.  So....the concept here is new windows and moisture control.  Of course, natural ventilation = open windows.  Not much you can do to control noise with open windows.  But green buildings are all about degrees of comfort, after all.

Becca Cavell
Thomas Hacker Architects
Portland, Oregon

March 4, 2007