Adding more mass to basement ceiling

One of the main principles described by Gervais in his book, is that mass is the most critical factor to sound isolation. However, it is not just mass on the "room inside a room", but the mass on the other side of the wall that is equally important.

Ideally my main level floor would have contained multiple levels of plywood flooring, providing extra mass to the basement ceiling. This was not the case, however Gervais provides a solution. This consists of attaching multiple layers of drywall to the underside of the main level floor, between the joists.

As you would imagine, this is no easy task. My builders have begun the work, and it is certainly time consuming but worthwhile. My next post will contain photos of the work, and some slight differences to the diagram above, that will save a lot of time.

Cycas - free drafting software

Update (Jan 2012): I would now recommend Google Sketchup software.

After some research of Linux-compatible free drafting software, I eventually settled on Cycas (http://www.cycas.de/). There is some learning curve, but after a couple of hours, it became fairly easy to use. There is also a large amount of documentation and tutorials available with the program, even if the below par German-English translation makes it hard to understand (most learning came by just messing around with the software).

I plan to use Cycas to draw floorplans, and may try and use some of the more advanced features such as 3D povray rendering from any perspective inside the basement (the Cycas gallery is impressive).

Here is my first attempt at the basement floorplan (red represents wood studs, white walls are concrete).

The preceeding months

For most of this year, I have been trying to read as much material as possible on the important factors in finishing a basement. In my case, the major two points are: Moisture and Sound proofing.

Although I've taken in knowledge from a variety of sources so far, I would say the best two are:

Home Recording Studio Build it Like the Pros by Gervais - The most detailed, practical and well-explained resource for building your own home recording studio. Almost all the principles apply to a home theater also.

http://www.buildingscience.com/index_html -A great site for moisture proofing and insulation. The most impressive thing about this site is that it describes the latest techniques in insulating your home - many of which contradict earlier techniques.

I will be referencing these throughout the build process.

Introduction

In 2008 my custom house was completed, taking a total of 6 months to complete. During the design phase we opted to include a full basement with poured concrete walls to keep the price down (instead of making the second level larger).

Since there are few time constraints, I have decided to attempt to finish the basement, mostly on my own.

The total area of the basement is about 1400 sq ft. The major function of the basement will be a home theater and a home recording studio. The major goal of this project is to create as much isolation between the home theater/studio and the rest of the house. I will attempt to do this on a fairly tight budget, but cutting no corners.

This blog will document the process of finishing my basement, including:
- Plans & drawings
- Photos & video
- Detailed documentation of sound proofing techniques
- Future proofing techniques
- Project planning tools
- Reference material