Does insulation go over or under wiring?

Asked By: Aureliano Pin | Last Updated: 16th January, 2020
Category: home and garden indoor environmental quality
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Insulation. After the wiring is in place, the insulation can be laid in. Most homes are insulated using batt or roll insulation. Other options, such as spray foam or loose insulation, are also a possibility, but in all cases the insulation needs to be installed after the wiring is done.

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Keeping this in view, can you lay insulation over electrical wires in attic?

If there is not anyinsulation in your attic, fit the insulation between the joists. Don't compress the insulation to fit behind pipes or wires. Instead cut to the middle of the batt's thickness so you have a flap under the wire and one over the wire.

Also Know, which comes first wiring or insulation? Wiring should be installed before any insulation. Electrical systems and insulation both need to be installed inside the wall cavities of your home, and it is important that they go in in the correct order.

Consequently, can you put insulation over pipes?

Protect pipes from freezing by lagging with foam tubes Lagging simply means adding insulation to the water pipes and is easy to do with foam tubes. It prevents them freezing and also helps any exposed hot water pipes retain their heat when running through unheated parts of the house.

Can fiberglass insulation touch electrical wires?

Be safe and smart with insulation, particularly in the garage and attic, to help prevent electrical fires. Don't let any insulation touch bare wires, and keep insulation fibers out of electrical outlet boxes. Unless you are an expert DIYer, hire a pro for safe insulation installation.

29 Related Question Answers Found

When should you use faced insulation?

Insulation in rolls, called batts, comes in two varieties: faced and unfaced. Faced, or the type with paper, is typically used in first-time applications, such as in walls, ceilings, floors, and in crawl spaces. Any time you use a faced insulation, the paper needs to be facing toward the living space.

Can electrical wires touch ductwork?

It can't touch hot air ducts. Cold air ducts it can touch. The reason it cannot touch hot air ducts is because the heat derates the current carrying capacity of the conductor.

Can you run wires through insulation?

Fishing Wires Through Cellulose
Cellulose insulation can be easy to fish the wiring through with the fish tape if it is loose-fill, but if it is glued-in, then it is significantly more difficult.

Is faced insulation better than Unfaced?

Faced insulation has Kraft paper on one side to act as a vapor retarder and help prevent moisture from entering the wall cavity. Unfaced insulation is insulation only, for use when a vapor retarder isn't needed.

Is it good to insulate interior walls?


Insulating interior walls isn't as common, although it offers homeowners some energy saving and sound-dampening benefits. The best time to insulate all walls is during new construction, but it's possible to add insulation to existing walls without tearing off the drywall.

Can junction boxes be covered with insulation?

Covering Junction Boxes
Even if the insulation doesn't create a fire hazard or render the box inaccessible, it does obscure its location. Some builders consider it safe to completely cover junction boxes in the attic with insulation as long as you mark the positions of the boxes.

Can I run electrical wire in attic?

An attic can be a hazardous work space. New lighting, cable, computer networking and sound systems can all require wiring that may need to come through the ceiling. On a single-story home or the the upper floor of a multiple story home, this means accessing your attic to run wire.

Does expanding foam damage wiring?

As it is, industry groups have conducted several decades of extensive testing, finding that spray foam insulation does not affect electrical wiring when safely applied and installed. Spray foam insulation is not corrosive to metal.

What type of electrical wire is used in attics?

Wiring in the attic is allowed to be non-metallic cable (NM cable), assuming that NM cable is allowed in your area. It is allowed in most areas of the US.

Can you use great stuff around electrical wires?


Sealing around electrical and cable lines.
GREAT STUFF PRO™ Gaps & Cracks is fireblock rated and fills those gaps, helping to impede the spread of smoke and flames.

Do you put plastic over insulation?

Back years ago, it was always said to NOT put a plastic vapor barrier over the insulation before hanging drywall or whatever material you decide to hang, as it would cause the room or building to act like a greenhouse.

What is faced insulation?

Faced insulation is a type of blanket insulation that is typically made of fiberglass. It differs from unfaced insulation only in that it has a vapor barrier (also called vapor retarder) that blocks moisture from moving from one space to another. The vapor barrier is usually made of kraft paper.

Is insulation flammable?

While the most common types of insulation found in homes today are fiber glass and cellulose, fiber glass is by far the most commonly used. And fiber glass stays nonflammable over the life of your home. Cellulose, however, is made from shredded and ground up newspapers, which are naturally flammable.

How do you insulate behind electrical outlets?

Seal around flush-mounted boxes, behind electrical cover plates. Another simple step for better outlet insulation is to apply foam or caulk into the gap around the flush-mounted box, behind electrical cover plates. After foam hardens, you can slice off the excess with a serrated knife.

Should I insulate around shower pipes?


Both hot- and cold-water pipes should be insulated when the goal is preventing freezing. If the goal is to lower water-heating costs, then it's wise to insulate hot water pipes wherever you have access to them.

How do you seal outside pipes?

Use caulk or canned spray foam to seal the holes made in rim joists for plumbing pipes. Keep the pipe runs close to the floor joists to avoid compressing the insulation. Use caulk or pre-fabricated gaskets to seal around the plumbing pipe penetrations in exterior walls.

What pipes should I insulate?

There are a few good reasons. If the basement or crawl space has uninsulated walls (and really, you should insulate your basement walls), insulated cold water pipes would be less prone to freezing in cold climates. If the basement is conditioned space, an insulated cold water pipe won't absorb heat.