Jim Ittenbach's Adventures in Soundproofing

Phase III:

I decided to use three layers of 5/8" sheet rock need to go in between the joists. This is done by cutting out sheetrock that will fit between the joist but leaving 1/4" around each edge. Using 4lb nails to hold the sheet rock in place the edges need to be caulked. Once all three layers are in place, 1X3 stock is attached to the rafters to hold the sheetrock in place. Also the cross braces that were removed while putting the sheetrock up, must be replaced. Then the insulation was put back up, along with fresh 3 mil plastic.

Lesson Learned: I had already purchase the Ultra Touch R-30 insulation and put it up. Once I took down that insulation and put three layers of sheetrock in between the rafters, I realized I no longer needed R-30 insulation. The extra space taken up by the sheet rock made it so I could have used R-21 Ultra Touch insulation instead. Ultra Touch insulation was a product I decided to try because it was made from cotton and does not make you itch. As to whether it is worth the extra cost or not I am not able to determine that at this point in time. If I had to do it again I would not only use a thin R rating and a less expensive product.

Before attempting to try this version of sound proofing make sure your structure can support the extra weight.

Another point to consider is how you will make sure there is sheet rock between all the joists. If you encounter sections where the joists are too close together to get a hammer in there, you can try using some drywall adhesive. If you have ductwork running between the joists, you will need to determine how you will address this situation. If you skip putting sheet rock up between those joists you will significantly reduce the performance of your system, as you lose both density and one of your leafs. Isolation requires two leaf systems: Density (such as sheet rock in multiple layers), space (with insulation) and density (a second leaf with more layers of sheet rock).

Lesson Learned: My membership a recoding.org introduced me to a member who brought to my attention to an aspect of my project that I was not aware of. My basement has 2X8 joists and my initial plan would have put me over the safe limit that my infrastructure could support. The dead weight load that 2X8 joists could support is 10lbs/square foot. At 2.2 lbs/square foot, my initial idea to put three layers of 5/8 inch sheetrock between the joists and two layers of 5/8 inch sheetrock on the final ceiling would have put me at eleven lbs/square foot. Even though I had to remove some of the work I had done previously, I am glad I discovered this limit before I finished everything. This an important thing to consider. You must understand the consequences of your design. A later design change would adjust my limitations (more on this later).

This phase is now officially (07/31/11) complete because the duct work was replaced and not the joists where the duct work was, also has two layers of sheet rock between those joists. The insulation has been put back up as well. There are two eight foot sections still left to put the insulation in, but I can use the insulation for the walls to do this, once I buy it.

My foam seahorse. I left a partially empty can of foam outside one night and the foam continued to slowly release for many hours. It actually wrapped all the way around the can and then created what I think looks like a seahorse.