Is it possible to lay insulation on electrical wires in the attic?

Content

What you need to know about wire insulation in the attic
What type of electrical wiring should I use for the attic?
Some tips for insulating your attic
The most common problems associated with attic insulation
Can the insulation touch electrical wires?
Cost of adding insulation
Is styrofoam suitable for attic insulation?

Laying insulation on an electrical wire is a subject that is often discussed. When it comes to the attic, it's even more important to get it right. For example, the wrong type of insulation or incorrect installation can lead to a fire. So, is it safe to insulate electrical wires in the attic?

Yes, you can run insulation over electrical wires in the attic. In addition, you can lay insulation around the junction boxes. However, ensure that the insulation is made of fiberglass and must be fireproof. These heaters should not reduce the flow of air from the house to the attic.

I will talk more about this in the next article.

What you need to know about wire insulation in the attic

Depending on the type of insulation, you can decide whether or not to lay the insulation over the wires.

For example, the insulation you plan to install in your attic needs to be non-combustible. That is why fiberglass insulation is most suitable for this kind of work. In addition, the selected insulation should not reduce the flow of air from the house to the attic.

Cellulose fiber is one of the most popular insulating materials that most people use for attic insulation. However, they are made from recycled paper, which can ignite under the right conditions.

Modern fiberglass insulation comes with a vapor barrier.

You can find this barrier on one side of the insulation which is made of paper. The vapor barrier always goes to the warm side of the attic. Look at the image above.

However, the vapor barrier should be facing the other way (up) if you are using air conditioning in your home.

You can also use a vapor barrier made of polyethylene.

What is vapor barrier?

A vapor barrier is a layer that prevents damage to the building structure by moisture. Polyethylene film and film are the most common vapor barrier materials. You can mount them on the wall, ceiling or attic.

Insulation around junction boxes?

Also, most people think they can't install insulation around junction boxes. But when you use fiberglass insulation, you can lay it around the junction box without any problems.

Quick-Tip: However, insulation must not be installed if the junction box is a heat source. Always remember, you don't want an electric fire in your attic, so avoid such things.

R-value for insulation

Speaking of isolation, I can't help but mention the R-value of isolation. You must have heard about it. But do you know what its meaning is?

In construction, the R value represents the ability to resist heat flow. It can be insulation, wall, window or ceiling; the value of r can affect their lifespan.

Regarding the insulation R-value, the following points may help you.

Use R-13 to R-23 insulation for exterior walls.
Use R-30, R-38 and R-49 for ceilings and attics.

What type of electrical wiring should I use for the attic?

You will be surprised to know that the type of insulation is not the only factor that affects attic insulation. The type of wire also plays an important role.

The best choice for attic wiring is non-metallic cable (NM cable). This type of wire is allowed in most regions of the United States. So be sure to discuss this with your contractor (if you are building a new home). Or contact a professional electrician if you want to check your old home for attic wiring.

Quick-Tip: Some types of wires are not suitable for a place like an attic. So, don't forget to double-check this.

Some tips for insulating your attic

When laying insulation in the attic, there are several points that should be given special attention. Here I will explain them to you one by one.

First of all, don't forget to seal around the wires with foam or caulk.

Then, before laying the insulation, lay a vapor barrier made of polyethylene. If you are using fiberglass insulation with a vapor barrier, there is no need to install polyethylene. Instead, lay the insulation vapor barrier on the warm side of the attic.

Quick-Tip: Don't forget to make slots in the insulation for electrical wires. You can use a sharp knife for this.

You can lay insulation on top of other insulation.

If you are using insulation that does not have a vapor barrier, you can install a second insulation without any problems. However, when laying insulation with a vapor barrier, remember that the vapor barrier side must not be laid on top of the previous insulation. It will retain moisture between the two heaters.. So, we remove the vapor barrier of the second insulation. Then place it over the old insulation.

Quick-Tip: Moisture between two insulations is never good, and it's the perfect environment for mold and mildew to grow.

Another thing you should pay attention to is the attic ventilation system. Without a proper ventilation system, an attic won't be able to maintain the warm or cool temperatures needed throughout the year. Therefore, make sure that the ventilation system is working properly.

If possible, take a thermal imaging examination. This will give you a clear idea of the attic temperature. In addition, it will indicate pests, leaks, and electrical problems in the attic.

important: Always wear a mask and gloves when installing fiberglass insulation.

The most common problems associated with attic insulation

Like it or not, attic insulation has several problems. One of the most common problems is wiring in the attic.

For example, most homes built in the 1960s and 70s have aluminum wiring. Aluminum wiring is good for many things, but not for attic wiring, and it will greatly increase the chance of an electrical fire in your attic. So before laying the insulation, it is recommended to check the attic wiring. (1)

Some homes built in the 1970s and 80s have fabric wiring in the attic. Like aluminum, it is also a fire hazard. So do not forget to get rid of such wiring.

Can the insulation touch electrical wires?

Yes, this is normal, given that the electrical wires are properly insulated.

Otherwise, the wires may heat up and cause a fire in the insulation. This is a serious problem when you install insulation in the attic. It doesn't matter if you use the best insulation on the market. If the electrical wires are not properly insulated, this can get you in a lot of trouble.

One uninsulated live wire can be hazardous to your attic. So try to avoid such situations.

Cost of adding insulation

Adding insulation will cost you between $1300 and $2500. Here are some of the factors that affect the cost of attic insulation.

Loft size
Insulation type
Labor cost

Is styrofoam suitable for attic insulation?

Yes, they are a really good choice. Spray foam insulation has a higher R value and is therefore ideal for attic insulation. However, installing spray foam insulation is not a do-it-yourself project and should be done by a professional.

On the other hand, fiberglass insulation is much easier to install and can be done by you without professional help. Therefore, labor costs will be minimal. (2)

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