Carpet Underlayment





SOUNDOWN’S Acoustic Carpet Underlayment is an important part of a boat's sound reduction package. This easy to install product can be used at any point in the insulation process. Carpet underlayment is effective as a primary treatment for living areas of the boat, such as solons or staterooms where flooring is the dominant source of moise in situations where it is difficult to install proper engine room insulation. Underlayment products consist of a foam layer supporting an acoustic vinyl barrier. The foam layer acts to decouple the mass layer from the floor vibrations,

creating an effective barrier against noise radiating from the floor due to structureborne or airborne sources of noise excitation.

Carpet underlayment is also very effective as part of a full insulation package. In cases where greater attenuation levels are required, carpet underlayment will improve upon the engine room insulation system. Not only will the carpet underlayment add a second decoupled mass, but it will also seal areas such as hatches where leakage can take place.

Material Configuration
Materials Total Thickness Foam Mass Layer
2 lb.ft, sq 1/2"
3/4 inch
1/2 inch thick
2 pounds per square foot
2 lb.ft, sq 1/4"
1/2 inch
1/4 inch thick
2 pounds per square foot
1 lb.ft, sq 1/2"
5/8 inch
1/2 inch thick
1 pound per square foot
1 lb.ft, sq 1/4"
3/8 inch
1/4 inch thick
1 pound per square foot
.5 lb.ft, sq 1/2"
9/16 inch
1/2 inch thick
1/2 pound per square foot
.5 lb.ft, sq 1/4"
5/16 inch
1/4 inch thick
1/2 pound per square foot
Barrier Foam Composits
The Material
Mass Layer
There are a number of formats for this product, each one consisting of one of the foams listed with a mass loaded vinyl layer bonded to the top.

Charcoal 1/4" and 1/2"

  • Soft underfoot feel compatible with softer carpeting
The mass portion of this material is a mass loaded vinyl, with a reducted slippage embossed surface, in densities from 1/2 lb. to 2 lb. per square foot.

Premium grade 1/4" & 1/2 "

  • Feel compatible with carpets requiring a firmer support.

Closed cell 1/4" & 1/2"

  • For use under all weather carpeting in areas of the boat that get wet.
Typical Physical Properties
1/4 to 3/4
Stiffness, MPA
ASTM 749
Weights (per ft2)
.55 lbs. to 2.2 lbs.
Tensile, PSI
ASTM D 412
Flammability, foam UL 94 HF-1 MVSS 302
In Testing, Call for Data
Elongation, %
ASTM D 412
Specific Gravity
ASTM D 798
Tear, lbs/1"
ASTM D 624
Shore A 2
ASTM D 2240
90 Nominal
Temp. Range, Fahrenheit (Composite)
-40 to 255 degrees
Enhanced Noise Reduction due to Carpet Underlayment

For a Printout of the Carpet Underlayment Specification Sheet in pdf format, click here
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