How to Soundproof a Floor – Soundproofing Floors

Serenity Mat UnderlaySoundproof Floors with Serenity Underlay
Serenity Mat™ Flooring Underlay is your noise control solutions for residential floors.These days most people want to remove carpet and pad from their floors. The build-up of dust and dirt makes many want to go to a hard surface that can be cleaned more easily. This is fine, except it makes the person below very aware of what you’re doing upstairs.

Typical sounds that travel through the floor and into the ceiling below are footsteps (impact noise), voices, stereos, barking, and even loud appliances. Noise (vibration) can easily transfer down through the floor / ceiling framing. Soundproofing the floor of your condo, townhouse or apartment can significantly reduce or eliminate this noisy intrusion and make your living space more peaceful and quiet for those around you. Before we recommend a system to block the noise, let’s find out what you’re up against.

Soundproofing Problem – Impact Noise: Impact noise, also known as footfall noise, occurs with an actual physical impact on the floor above. Might be a footstep or a chair dragging on the floor. Impact noise can also be from objects being moved or rolled across the floor, or vibrations such as those from a washer or dryer.

The simple fact is treating impact noise is much more difficult than treating airborne noise. The significant difference between the two is the amount of energy produced per square inch. Illustrated below is a comparison for energy produced by airborne noise and impacted noise.

An actual foot striking the floor results in an enormous amount of energy per square inch entering and exiting the floor assembly.

A recording of a footfall strike played through a speaker results in very little energy entering and exiting the floor per square inch.

The actual impact noise is therefore much more of a problem than airborne noise.

How Serenity Mat Works

Compare the springs on the right. The first spring is in a resting state and uncompressed. If we apply energy to the top of the spring it compresses, then will oscillate up and down until it comes to rest expending all the compression energy. Serenity Mat™ behaves just like the spring.

All of this takes place in a fraction of a second. Serenity Mat™ Flooring Underlay uses a proprietary blend of recycled rubber with different density (Durometer) material to broaden the effective frequency range of isolation.

Because of the need for oscillation to reduce the impact, we have to take care not to insert screws and nails that will lock the movement of the mat and reduce oscillations. Nails and screws will partially reduce the performance.

Nailed Down Wood Floor Installation Diagram

Note that nail-down hardwood flooring requires a nail base of two sheets of plywood. These two layers are cinched together with short screws. These screws cannot be so long as to penetrate the rubber layer. The finished hardwood floor and nail-base are “floating” on the Serenity Mat™.

Option 2:
Glue down the Serenity Mat to the original subfloor (could be a slab or wood frame). Then glue down a layer of 3/4″ Tongue & Groove OSB. OSB resists warping better than plywood.

Take care if the floor has valleys & crowns as the plywood may not lay flat. This may require a concrete Tapcon screw to be installed and later removed when the glue dries. You can set a bag of sand or heavy object as well.

Engineered Floor Installation Diagram

Leave a gap from the floor and the wall.

Unlike nailed wood floors, engineered floors require no fasteners to install. The engineered floor is “floating” on the Serenity Mat™. Using Serenity Mat™ underlayment helps to decouple the floated floor from the original subfloor, reducing the sound traveling to the room below.

Note that because of the severity of the impact vibration, a layered approach is recommended if possible.

Best Soundproofing a Floor and Ceiling Solution

Serenity Mat™ + Clips/Drywall Furring Channel + Green Glue

This solution finally addresses the noise vibration right at its source by applying mass and damping to the underside of the problematic subfloor. Because this method directly addresses the vibration, there will be much less sound available to travel to the joists as well as your walls below. Keep in mind that your walls are holding up his noisy floor above.

Ease and Cost Performance
  • More expensive than the other ceiling solutions Still simple and straight forward
  • Slower than the other ceiling solutions
  • Primary labor issue is associated with the removal and disposal of the original ceiling.
By directly addressing the vibration at the source (the subfloor above) we are able to reduce the vibration before it travels far.

This method adds Decoupling, Mass, Absorption and Damping, four of the 4 Elements of Soundproofing.

FAQ – Frequently Asked Question about Serenity Mat™

Q – What is the difference between thinner and thicker underlayments?

A – Mass is a big contribution of soundproofing underlayment. The thicker the underlay is layers means it will oscillate more slowly. This slower oscillation with help guard against lower frequencies better than thinner underlays. Average mid-frequency noise is audibly improved as the thickness increases.

Q – Can I build walls on Serenity Mat™ Soundproofing Floor Underlay?

A – You can. You’ll be anchoring to the upper ply layer floated on rubber. Easier to attach wall plates to the original subfloor or slab.

Q – Do I use Glue when installing Serenity Mat™?

A – Glue is recommended. The glue assists with sound isolation as well as keeping the rubber from shifting during flooring installation.

Q – What if I want to protect the old floor and don’t want to glue to it?

A- Float the new floor. Cover old floor with the rubber without adhesive.