TM Soundproofing How To Soundproof

How To Soundproof

Topics Covered in this Article:

This soundproofing article follows the Soundproofing Basics article and is intended to give a step by step instruction on how to soundproof a home, hotel, condo or office that is under new construction.

In our Soundproofing Walls & Ceiling article we address retrofit soundproofing for existing floors, walls and ceilings.

[As with all the articles in our Soundproofing Series, this is a practical, short and concise overview. For more in depth understanding of the science behind sound control, please browse our Understanding Soundproofing articles on the main menu].

FLOORS

Being that the sub floors are put down as part of the framing we will begin with soundproofing the floors.

The Challenge: Aside for airborne sound coming through the ceiling, soundproofing floors face an additional challenge called Impact Noise (e.g. footsteps or an object being dropped, see Figure #1 below). Impact Noise is very difficult to control since the impact actually shakes the entire structure, creating vibrations.

How Impact Noise Affects Soundproofing

Labs often test Impact Noise, called IIC (Impact Insulation Class), however they use a tapping machine which does not compare to heavy footsteps or items being dropped. This lowers the accuracy and reliability of the test results and your structure may not perform well in actual life conditions.

To counter this problem, there are many Floor Underlayment products being sold on the soundproofing market, some at very steep prices, with varying degrees of effectiveness. We cannot claim that we have tested every one of them; however, judging by the amount of customers calling us complaining about the inadequacy of their existing floor systems and the positive feedback we receive after offering our soundproofing advice, we are certain that the products we recommend and offer are unsurpassed. As a plus, our systems can be purchased at a fraction of the higher end product costs.

The Solution: Due to the complexity involved in soundproofing floors, we try to utilize as many techniques as we can in the system. Therefore, we will start with the most effective system and also mention an option of a lesser degree, for those who are on a budget.

1) Install Your Flooring:

Joist Gasket Tape for Soundproofing Walls, Ceiling and FloorsA) Start by applying Joist Gasket Tape on each of the floor joists. This closed cell tape will decrease footfall and impact noise and some airborne noise. Additionally this will eliminate future floor squeaks which occur from the sub floor rubbing against the floor joists.

[Customer Review: "I am VERY glad I went with that choice. I and all the guys helping me with the installation couldn't believe what a difference this joist tape made. It certainly prevents problems associated with direct contact between the joists and the subfloor, and there seems to be validity to the statement that it reduces transfer of footfall noise."]

Green Glue Noise-proofing Compound for Soundproofing

B) Above your Joist Gasket Tape and Joists, install your sub floor and apply Green Glue Noiseproofing Compound onto it, using two tubes for every 4” x 8” sheet.

C) Add a 2nd layer of Subfloor perpendicular to the first layer sandwiching the Green Glue in between. Screw down the 2nd layer to the floor joist as you would to a typical subfloor.

D) (Optional: For greater footfall sound control, lay down Rubber Underlayment before applying finished floor).

Completed Floor Layout

Complete floor layers should look as follows (See Figure to the Right):

  • Joists
  • Joist Gasket Tape
  • Sub Floor
  • Green Glue
  • Sub Floor
  • Rubber Underlayment

 

 

 

 

 

 

Tip: Installing the above steps before framing your walls will give you the best results as this will prevent sound seepage through the wall framing and will give you one continuous sound barrier with no breaks.

2) (Caulking: If you installed the 2nd layer once your walls were frames; Caulk the perimeter of the room with a high quality Acoustical Caulk to ensure a proper seal). 

3) Apply Floor Covering: Install your floor as you would above any sub floor. If you are applying carpet, we recommend installing the thickest Carpet Underlayment possible. (You can go all out and use a premium carpet underlayment).

You have now completed half the job - the other half will be securing the ceiling below the floor, as follows:

CEILING

How Ceilings Effect SoundproofingEven with your walls and floors fully soundproof, sound waves can still travel through your ceiling if it is not properly fortified, see figure to the left.

To counter this problem:

1) (Optional - Apply Green Glue with Strips of Drywall: For superior sound control, cut strips of drywall to fit in between the ceiling joists. Apply Green Glue on the strips and screw into the underside of the sub floor, sandwiching the green glue between the sub floor and drywall.

You can double up by doing the same thing with another strip of drywall over the first. This step may be omitted if you are on a budget or if it involves too much labor for your project).

R19 Fiberglass Batts for Soundproofing and Insulation2) Apply Insulation: Install Fiberglass Batts in between your ceiling joists; be sure to put some on top of any recessed lighting that you may have.

Tip: Keep recessed lights and HV/AC ducts to a minimum on ceilings that you are trying to soundproof. (We generally find that if the floor and ceiling are done as described, there should not be any major issues with the recessed lighting. However, for the perfectionist, or in a case when there is a lot of recessed lighting, they may need to be boxed around. Details will be discussed in a different article).

Tip: Use flex duct, not rigid metal, for any ductwork running through your soundproofing projects.

3) Install Resilient Sound Clips on your ceiling joists.

Complete Installation of RSIC Clips and InsulationFor detailed installation information, see our Resilient Sound Clip Installation Guide.

4) Apply Hat Channels: Run 7/8” Wide, .25” gauge Hat Channel through your clips, overlapping all ends by at least six inches and screwing together with self-drilling sheet metal screws.

5) Apply Drywall: Raise your drywall into place and screw into channels using recommended drywall screws. [Do not attach drywall to ceiling joists in any way as this will compromise the floating ceiling that you have created].

6) Add Green Glue and Another Drywall: Apply Green Glue to the back of a 2nd sheet of drywall, using 2 tubes for every 4” x 8” sheet. Screw the 2nd sheet of drywall into channels using longer screws. (This step can be omitted if you are on a budget, especially if you have installed the Green Glue on the floor above).

Acoustical Caulk Used on Perimeter of Room for Superior Soundproofing7) Caulk: Caulk the perimeter (and the seams, if you only used 1 layer of drywall) using high quality Acoustical Caulk. Additionally, caulk the space between the recessed lighting and the drywall.

WALLS

1) Add Insulation: Install fiberglass in between the studs (R-11 Insulation Batts for a 2x4" Framing and R-19 Insulation Batts for 2x6" Framing).

2) Install Resilient Sound Clips on the face of the studs using the following guide: Whisper Clips Installation Guide.

3) Follow Steps 4-7 in Ceilings (apply Hat Channels, apply Drywall, apply Green Glue, apply another layer of Drywall and Caulk) See images below.

Complete Wall Layout for Soundproofing Complete Wall Layout for Soundproofing

4) Seal Electric Boxes: Make sure to seal around all electrical outlets and close up all holes. To easily sound seal electrical outlets, we recommend applying our STC Seal for Outlet and Electrical Boxes, which can be added after the drywall has been applied. (Acoustical Outlet Putty Pads can also be used, however these need to be added before drywall is installed).

5) Alternative: Another simple option is to install 2 layers of drywall with Green Glue directly onto the studs.

Tip: We HIGHLY recommend treating the ceiling of the room the same way as the wall, due to high percentage of sound leaks over the walls thru the ceiling, as noted above.

The obvious question that we are frequently asked is: Do I need the clips on the wall or is the green glue alone enough? The answer depends on what level of soundproofing you are looking to achieve, what type of noise you are trying to block, and if you have access to both sides of the wall.

If the noise you are trying to control is standard talking, phone ringing, and some music, then you will have a tolerant level by using drywall and Green Glue, either by doing it on both sides of the wall, or by doubling up on one side. (Whenever possible, always try to soundproof the noise source side). However, if the noise is extremely loud or very low bass, like a loud home theater (where you can feel the vibrations), or you want the best soundproof wall available, then you should use the Whisper Clips and a double layer of drywall, with Green Glue on the other side or on the side of the clips.

DOORS

There are three main components to sound proofing a door: Mass, Damping and proper Sealing.

1) Mass: To add mass to your door, use flat panel, solid core doors and add a ½" Medium Density Fiberboard (MDF) panel to it.

2) Damping: Adding Green Glue Noiseproofing Compound between the MDF and door creates damping.

3) Sealing: Use Automatic Door Bottoms, Door Gaskets and other Soundproofing Door Hardware to firmly seal the gaps around the door.

For more detailed info see our How to Soundproof a Door article.


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