How to Cut Insulation Foam Board

Lots of brands are manufacturing these insulation boards. And they offer different lengths, colors, and customizations. When a building or construction body has a cavity, it needs to be fixed. At that point, foam board insulation is a popular choice. Structural Engineers think about a comparatively energy-saving solution and gives them the freedom to control buildings’ indoor temperature.

Due to so many available options chances of choosing the wrong one is also high. So, it’s better to educate yourself a bit on Foam Board Insulation, features, and cutting methods before you straight go for cutting a foam board insulation. This article is going to guide me through.

What is Foam Board Insulation?

Foam Board Insulation is a stiff board made of polystyrene, polyisocyanurate, and polyurethane for insulation purposes. This board is used to insulate buildings’ decayed parts, especially when it is open or exposed. Sometimes the drywall is down while remodeling a house. This insulation board can also be used in that case. These boards are energy efficient and can reduce noise to some extent.

These three are the most common items to make Foam Board Insulation.  Polystyrene is a thermoplastic. Polyisocyanurate is also known as Polyiso. It is a type of plastic. Polyurethane is also plastic material.

What are the Best Tools for Cutting Foam Insulation Board?

There are plenty available interesting tools to cut a foam insulation board. Let’s check out short know-how about them:

Utility Knife:

A utility knife is one of the cheapest and easiest tools for cutting this rigid board. It cuts almost smoothly. There is a possibility of getting different slopes on different edges of the board, probably because you are still kind of an amateur. Still, the cut is pretty neat.

Worktable:

this is a must tool. Regardless of whatever cutting tool you choose, it would help if you placed your foam board on a reliable worktable. Make sure it does not tremble while working. Because if you go for tools that need a plug-in like a jigsaw, you need a strong table.

Felt-tip Marker:

In your school days, you remember kids putting dots first on the paper to draw a perfectly straight line. It is always safe to do some little pre-tasks to make the main task easier. Before you cut your foam board, draw the line at first. Otherwise, there is a big chance the cut would not be in a straight line. Why felt-tip marker? Because it will help you see the line.

Circular Saw:

Also known as SKILSAW. It gives you a neater cut. Due to the sharp teeth-type edges, the paper on the board gets a little messy. So, it is better to put a mask on and keep a duster before you use the saw. If you go for a circular, I saw my suggestion to get one with a fine-tooth. It will get the job done quicker.

Goggles:

Cutting the board would create dust particles. Tools with no plug-in like a utility knife might not create a problem. But using tools with plug-ins makes specks of dust spread in the air. And it would help if you did not take a risk about your eyes. Even a tiny dust particle in your eyes might turn into very harmful for you. So, use goggles while cutting or welding.

Jigsaw:

If your board is thicker, then I would recommend going for a jigsaw.

Metal Cutting or All-purpose Jigsaw Blade:

you will have a lot of different metal-cutting jigsaw blades now. These blades will give you quite an impressive result since the edges are comparatively consistent and it’s fast. But the downside is the area, and the boards are going to be quite messy.

Old Steel Circular Saw Blade:

it will give you comparatively a less messy cut. I mean, dust would be very little. And the cut will be way smoother. On top of that, it is not that pricy at all.

Vise:

This apparatus is for measurements and holding your tools while cutting or smoothening.

Grinder:

Sometimes, you might find that you are uncomfortable working with saw-type tools, or saw-tooth structures are not smooth enough for your board. You can take a grinder and make those saw tools as per your requirements when doing it yourself at home or in a workshop.

Cutting Foam Board Insulation

As it is mentioned already that foam board insulation has a versatile utility nowadays. Only fixing an open cavity is not its job anymore. Sculpting is another job for these boards now. We already gave some details about the tools you are going to need. Now it is time to throw a shed on how to cut these boards. We are going to discuss it in two parts. Because in my opinion, before going straight to the cutting methods you also need to know about some small preparations. It will make your main task more accessible and more pleasing. So we will discuss some preparations a little bit and then methods of cutting rigid foam board insulations.

*Preparation of the Cut Process: keep in mind that these preparations are essential. These are more like essential tips, to be honest.

1. Measure Your Cut: measurement is significant. You do not want a foam board that does not fit in properly the building cavity. Or, you do not want to ruin your sculpture just because the foam board is not a right fit by size. Right? Always, always measure your cut before beginning. Measure your construction holes or your sculptures, and then measure the board. Also, measure how thin or thick the board is before buying it. Nowadays, foam board insulation comes in a variety of lengths and breadth.
2. Mark Your Cutting Line: marking the line would ensure you a fine cutting line. In this article, I recommended a felt-tip marker. It will make the line bold and more transparent. It will ease your task of cutting the board. You do not need to stop in the middle of cutting and check if the line is going as you wanted or not. Hence, it is time-saving.
3. Clean The Area: whichever cutting tool you pick will make bags of dust. Some tools make more specks of dust, some little. So, keep the area clean. And also, keep dusting tools and some papers around so that you can easily clean the area after cutting is done. Knives or circular saws will make specks of dust. But other options are pretty messy for your area. So, could you keep it clean before you start the work? It will make you after work cleaning quicker.

 *Methods: now, we will talk about methods. Methods and cutting tools should be different depending on the rigid foam board thickness. You will find from 1/2 (Half) inch to 2 (two) inches thickness range. The usual length is 4 inches *8 inches. But the main feature to keep in mind is the thickness.

1. Cut Thin Sheets with Utility Knife: Before we get to the knife details, I must mention that check your worktable. Place the board on the worktable at first. And then place the board facing down lying on the table. It will ease the cutting. Then take the measurement. Draw the line. The foil backing of the foam board insulation will help you to draw a perfect cut line. Draw the line with a felt-tip marker. Then use the knife.

Any pro-worker will suggest you use an extended knife (if you are using a utility knife). It is available, cheap, and accessible. But again, that depends on the thickness of the foam sheet. The typical length of the extended blade of a utility knife is 1 (one) inch. So, I would recommend it for half an inch thin foam board cutting. It is a perfect option. Cut through the back foil. And do not stop or judge the cut just right after doing it once. Keep cutting again and again until the blade penetrates perfectly through the board. Do not get scared seeing “again and again.” It will take only 2 (two) to 3 (three0 times).

2. Cutting Rigid Foam with A Circular Saw: We talked about ½ inch foam boards in the previous method. Now, if the sheets are 1 to 2 inches thick, what would you choose? You will probably go for a knife with a longer blade. Right? But what if you need to cut a lot of foam boards of 1 or 2 inches for building insulation? Then it is time to choose something better. Saws are better options. But I would suggest a circular saw without hesitating for a single moment. It will give you perfect-90 smooth cuts.

You can opt for any other saw. I tried to give a glimpse about jigsaw, all-purpose jigsaw blades. The issue with other jigsaws or saws is the amount of flying dust on the sheet is way higher. So, the method area gets more untidy. And also gets riskier for your eyes. Now, you can always clean after your work is done. But do not forget to put on goggles. Even one single foam flake is enough to ruin your eyesight or give you eyesore.

3. Cutting with A Drywall Saw: When you remodel your wall, you need to downing your drywall. If you follow some techniques, then it will not take much time to cut drywall. Drywall is a construction panel that is also used as direct support for designing purposes.

It is like a sandwich. On both edges, there are two paperboards and two gypsums. Now, you can cut your foam boards with these drywall Saws too!! Just put enough pressure since it is not a small tool. Also, drywall saw usually works better if you hang the board with a proper board holder and hold the board with another hand. It keeps the board steady while cutting. Not to mention, you will need to measure the board, draw the cutting line, and a utility knife to get a good cut using the saw. Remember, with proper techniques and tools, handling a drywall saw is an easy job.

4. Cutting Foam Insulation Board with A Jigsaw: again, the jigsaw is an option for thick foam boards. Sawteeth can come in different sizes—the smaller the teeth smoother the cuts. Because the length of the gap between teeth decides the amount of air, it takes a while to cut anything. That also controls the number of flying specks of dust from the foam sheet. So my suggestion would be a few teeth as possible.

You can also make your cutting saw with a grinder quickly. You will have to put the blade in a vise and grind it. This saw will last longer.

5. Cutting Foam Insulation Board with A Dremel: Dremel is a brand. It is not a type of tool. This brand has several rotary tools which come with different models. They have rotary products for cutting, polishing, sharpening. You can control rotation speed with their tools. The speed range is 5000 to 35000 rpm. So, if you want to smooth and quick cuts, you can go for the fastest given speed. Or, as per your requirement you can choose. EZ:456 and EZ:402 are good to use for cutting. Make sure you tighten the collet nut while placing the mandrel lock in the collet. Place the bowtie after that. Then place the wheel blade below the bowtie on the mandrel. You will need to rotate and twist 90 degrees until it tightly fits and align properly. Then hold the foam board firmly with one hand and hold the Dremel with another one. Cut the board. And also, do not forget to take the basic preparations we spoke about earlier.

Conclusion:

My utmost purpose was to let you know that cutting a foam board insulation is easy to work. You only need to understand the tools and the size of the sheet before doing so. There are also other cutting machines like Irwin Dovetail Flush-cut pull saw, Dewalt Japanese Pull saw, Craftsmen western style saw, and many more. I only shared which I tried and found pretty much good results. I encourage you to do some experiments at home before you go for the main task. There is no harm in experimenting and understanding different ways. We just tried to help you make a good decision when you do not have that much time.