Home Improvement--General/Insulation question...


Mr. Wood,
I've got a 4x8 sheet of Dow styrofoam "Scoreboard" insulation (one and one-half inches thick), and I need to cut it into smaller pieces.  What's the best way to cut it and get a fairly clean edge?  I have a circular saw with a plywood blade on it, and I also have a Rockwell "versacut" mini circular saw.  Is there a special kind of blade professionals use, or do you just have to use a utility knife with a new blade?
Any advice...suggestions...tremendously appreciated.
Warm regards,


Many professionals use hot wire cutters, that as the name implies utilizes a heated wire to cut (melt) the styrofoam.

If using a circular saw a fine tooth blade is best to prevent tear out as the blade clears the top of the sheet. Use a silicone spray lubricant on the blade or rub wax on the blade to reduce friction.  Applying a piece of tape, centered over the cut line may also help prevent surface tear out. Test the tape, on a scrap piece or inconspicuous area of the styrofoam, to make sure it doesn't damage the surface when it is removed.  

Other options include:

A jigsaw with a fine tooth blade.  lubricating the blade and using tape on the surface will help here also.

A disposable utility knife, of the type that has snap off segments. The blade can be extended enough to reach completely through the sheet.  Lubricate the blade for best results and make multiple passes to complete the cut.

A fine tooth hacksaw blade with tape wrapped around one end to form a handle is an inexpensive way to saw the styrofoam and produces a nice finish if done carefully.

Good Luck with your project.

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Tony Wood


I can answer a wide range of home improvement and maintenance questions. My expertise is in carpentry, painting, framing, siding/boxing, doors, windows, decks and screen and glass enclosures. Wood's Home Maintenance Service


I am a life time resident of North Carolina with over 30 years experience in multiple facets of the industrial, commercial and residential construction industry. For the past 23 years I have owned and operated Wood's Home Maintenance Service , providing services primarily in Johnston, Wake and Sampson Counties of North Carolina.


Several Home improvement articles published on Angie's List and other online forums.

High School graduate ~ proficient in CAD (computer aided design), Open Office program suite.

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