How to Use a Wood Router to Cut Foam Board Insulation

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  • 1 hours
  • Beginner
  • 70-150
What You'll Need
Air or electric driven router
Foam board
Guide template
Pencil or marker

Foam insulation board is made out of coagulated foam and carries the appearance of condensed plywood. Available in a variety of colors, it is a widely used material in the home, visible on ceilings and walls in its capacity as an insulator. A hot cutting method is usually used to incise this type of board as it is made out of expanded foam. However, if this means is not available then a wood router can act as a substitute. A wood router is a tool used to hollow out wood surfaces, commonly favored by those who specialize in wood patterns or staircase banister designs. The router has mechanized over time and now cutting that foam board should only take a few minutes.

Buy a Foam Board

Buy a high quality insulated foam board from either insulation contractors or your nearest hardware store. They are also available online for order.

Draw the Layout

Take the template of the design that you wish to cut out of the foam board and mark the points using a pencil or a marker or just draw out the entire layout on the foam board as lightly as possible.

Cutting the Foam Board

The higher the density of your foam board, the better the result. If this is the case and depending on your design, you can cut a couple of inches into your foam board and expect excellent results. However, as foam boards comprise of different layers, you may encounter resistance depending on the level at which you are cutting.

However, as varied as foam board colors are, each hue has its own problems. Blue insulation is a good choice, but it burns fast and you will have to get the router going quickly to get a clean cut. White foam boards have little beads making them weak, and they are therefore a poor choice as they will shred almost instantly when you use the router.

Finishing the Job

Break off the rigid insulating board or alternatively, use your hand to push out the cutout from the foam board frame. Erase any markings that you may have left on your cutout if any.


Depending on your intention for the board, this cutting can be easily done with a sharp blade, like a Stanley knife, a serrated kitchen knife, or even a wood saw. All these would be sensible choices if you were only creating shapes and other small designs out of your foam board. However, if it is an entire wall or door, that is the basis of your project then the sturdier wood router can be incorporated.