How to cut fiber insulation without problems

Insulation is a basic element in construction. If our walls and ceilings are not made of solid concrete, we have to fill in the space created by the plywood. This is the only way the wall is resistant, does not allow insects to enter and maintains the best temperature. For cost and features, fiber is the most popular isolator, but it is difficult to work with. If you want to know how to cut fiber optic insulation without accidents, you’ve come to the right place.

Fiberglass is usually found in spongy fiberglass or glass wool presentations. This is placed in panels inside the walls to avoid bending as much as possible, otherwise the thermal resistance of the material will be affected.

In order not to bend it, it has to be cut. Cutting fiber is a risky job if we don’t know how to do it. If you’ve ever touched fiber directly with your hands, you know that this is one of the worst mistakes you can make, as it will seriously irritate your skin.

As if that weren’t enough, cutting isn’t easy either, as it’s a flexible material with thick layers and comes in long fiberglass insulating rolls. Working with fiber is a challenge, but we can make the process suitable for everyone.

Glass fiber hazards

We have hinted at this before, but it is good that we remember it before we start. Fiberglass is a combination of tiny glass particles. These cause skin irritation when we touch them directly.

The particles can also fly through the air and cause terrible itching. In the worst case, we could inhale the fiber and develop severe allergies and irritation to the respiratory tract.

If we don’t have the appropriate safeguards in place, it’s best not to try cutting fiber.

How To Cut Fiber Insulation – The Right Way

Before you start, you need to be sure that you have all the tools you need to cut the insulation. The most important thing (after protection) is the insulation knife. You need to have several extra blades to replace them every time they shatter.

To ensure a perfect cut, you need a carpenter frame. This helps compress the fiber when cutting and makes it easier to push the knife.

Protection is important.

We don’t have to wear a full suit to protect ourselves from fiberglass, but it is advisable to wear a long-sleeved shirt and trousers on the heels.

The feet can be protected with long socks and tight shoes, preferably with sports shoes that you no longer wear. A cap is also a good addition to your set.

For the face you need protective glasses with side protection as well as a mask or dust mask so that the glass fiber particles are not inhaled when cutting.

Find a smooth surface to cut

If we do not want imperfections when cutting the insulation boards, we have to lay them on a flat surface.

It is not advisable to do this on ceramics or the like as you will leave cracks with the knife. Concrete is also not an option as it damages the edge of the blade. It is best to use a plywood sheet or plastic blanket that has been specially designed for the craft.

The trick of 2 × 4 plywood

To speed up fiberglass cutting, we can use a 2 x 4 plywood as a guide. We’ll just lay the plywood over the fiber and try to cut the fiber an additional 12 inches.

These measures are enough to have constant guidance to the fiberglass plates that we are going to cut, and we have enough space to rest on them and use them as a press.

Mark the cutting lines

Before cutting, it’s best to mark each of the cuts we’re going to make. To do this, you need to completely unwind the glass fiber and draw straight lines on the film with a pencil that holds the insulation.

Press firmly

The plywood sheet must be pressed hard on the glass fiber so that it remains as compressed as possible when cutting. It is practically impossible to get a precise cut when it is in its spongy shape.

There are two ways to apply this pressure. The first is with brute force, putting our body weight on the plywood board when we make the cuts on the floor, or applying pressure on the wood with our free hand when we are working on a table. The second is to put heavy objects on the wood.

How to cut fiberglass insulation with a knife

Place the plywood sheet that we use to compress the fiber onto the mark we made earlier with a pencil (as if it were a ruler). The blade knife must be exposed at least 5 cm to cut the glass fiber.

With a fixed pulse, place the blade close to the edge of the plate and start cutting the fiber. Hold the blade as close as possible to a 45 degree angle. If the blade is sharp, a single cut should be enough to separate the blade.

If our fiberglass contains a decorative coating, make sure it faces the floor to avoid damage.

Before inserting the cut sheets, remove excess and defective parts by hand (with gloves).

Adaptation to strange measures

Although the fiber optic rollers are supplied with the standard measures to adapt to the gaps between the carriers, we do not have to cut sheets in special sizes to fill certain places.

An example is the spaces between a door, above and below a window or the last corners of a wall.

In these cases, measure the height and width of these spaces and cut off a piece of fiberglass insulation that has an extra inch in both directions. This ensures that it fits without being overly tight.

Last minute settings

We can make certain fixes once we have installed the fiber on our wall or floor. Just keep in mind that you can scratch the wooden frame if you’re not careful.

The positive side is that the carriers usually work to cut off excess insulation accurately. In this case, you need to tighten the fiber to compress it and fold it in the corner that connects the wall to the floor of your building. Now just cut along the corner.

However, we remind you that there is no problem if the fiber is a little dense. If the excess is not large, you should simply leave it there.

Carry out a new installation

Now that you know how to cut fiber insulation, you need to know how to clean it. Dust and particles that arise during construction work should be collected with a vacuum cleaner.

The problem is that this is not enough to clean the airborne fiber. To do this, water must be sprayed with a sprayer. In this way, the particles become heavy and fall to the ground.

The clothes with which you installed the fiber optic should be washed separately from the others. After washing, you need to clean the wash cylinder to remove glass particles. You will also need to clean the walls of the tub or shower after bathing.

We have already protected our building

Now you can take full advantage of fiber optic insulation. While its installation can be intimidating, it is still the best material for walls and floors.

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