How to Insulate an Engine Compartment on a Boat

by Kevin Leeper

Boat engine compartments can be a source of unwanted noise, especially on an older boat or on a boat that has lost its original insulation from wear or rot. The noise projected from the engine compartment of a boat can be reduced by simply adding some new sound-suppressing insulation. The simplest insulation to install is backed with PSA, which stands for Pressure Sensitive Adhesive. By removing a plastic backing, the special foam insulation self-adheres to the inside of the engine compartment.

Open the engine cover and inspect the area where the insulation will be attached. The surface needs to be clean and dry. If applying to a smooth surface, scuff it with sandpaper, then remove any dust from the contact area.

Measure the inside of the engine cover using a tape measure. Lay the insulation out with the adhesive side facing down on a clean flat surface. Draw a line on the insulation with a pencil where the cuts need to be made.

Compress the foam insulation along the pencil line with a level and cut along the line using a sharp utility knife.

Make some reference marks with the pencil on the engine cover, if desired, to act as a guide and simplify placement of the insulation. Use the level to assure straight lines.

Peel the first few inches of the backing from the top of the insulation and press the insulation into place on the engine cover, using the pencil marks as a guide. Remove the rest of the backing and press firmly on the insulation to insure good adhesion to the surface of the engine cover. Continue this process until the inside of the engine cover is completely lined with insulation.

Tape all insulation seams and outer edges with reinforced foil tape.


  • check When applying the insulation, it is important to press firmly and allow the adhesive to make good contact. Take care not to stretch the insulation while applying. If stretched, the insulation may pull loose from the engine cover.

Items you will need

About the Author

Kevin Leeper has worked in video production since 2002 and currently runs a video services company. He holds an Associate in Applied Science in electronics and computer technology, as well as a Bachelor of Science in technical management, from DeVry University.