"It's in the details"... 

Soundproofing is all about the details, the smallest factor can make a big difference in the end results of your project.  This blog post will explain how to properly seal the ceiling / wall joint for a Green Glue soundproof room.   This joint is a critical weakness for a room since it's a potentially large gap that could allow unwanted airflow.  Keep in mind that sound travels like water, it finds the path of least resistance.  That's why caulking ceiling wall joints with a noiseproofing compound is so important. 

Green Glue Noiseproofing Ceiling / Wall:

For Green Glue Noiseproofing Compound to work, the compound is sandwiched between two layers of drywall.  Because there will be 4 different layers of drywall, our goal is to create a "Z joint" as opposed to a traditional "I joint".  Most walls and ceilings will have an I joint which is simply spackle or joint compound filling the gab between the wall and ceiling.

Common I Joint:  

In the diagram below, the bottom wall joint is a traditional I joint that can provide a straight shot for sound transmission.  If not properly planned, a wall will be built prior to work starting on the ceiling.  Because the wall and ceiling are constructed at different points of the project, the joint will result in a straight channel.

The Z Joint:

The top wall joint shows a Z joint which provides a labyrinth like path for sound transmission.  The Z joint utilizes all 4 layers of drywall and staggers the wall and ceiling layers to create three separate channels that will be filled with acoustical sealant.  Sound transmission will be limited in this type of joint.

The L Joint:

In retrofit soundproofing projects the ceiling / wall joint will be an I joint, however an L Joint will easily be achieved since only one layer is being installed on both the wall and ceiling.  In retrofit projects achieving a Z Joint is not possible.

MOST RECENT BLOG POSTS
-Fab Strap Seal Crimping Tool
-Soundproofing Project Reasonable Expectations and STC Rating Definitions
-Four Steps to Asbestos Pipe Insulation Encapsulation
-Fiberglass Pipe Insulation Accessory Items You May Need
-Owens Corning ASJ Max Pipe Insulation Code Compliance
-Fiberlock Lag Kote II Asbestos Encapsulating Sealant
-No-Frame Fiberglass Edge Coating for Frameless Acoustical Panels
-Fiberglass Pipe Insulation Install Saves Big Dollars