Can You Use Loose Fill Insulation In Walls?

Loose-fill insulation is a classic choice for attics, crawl spaces, and the like. But if you live in an old house, you might need insulation in more than just the attic. You might not even have insulation in the walls! So can you use loose-fill insulation in walls, too? We've checked with contractors for everything you need to know.

You can use loose-fill insulation in walls. It's the easiest way to add insulation when you don't want to tear down existing walls. You can add loose-fill material through small holes in the wall. Use a blower to pump the insulation into the wall cavity.

In this article, we'll explain what loose-fill insulation is. We'll cover how it's different from batting and how it's used. We'll explain whether you need a pro for the job. And not just that, but do you need a vapor barrier? We'll get to all that and more, so read on!

An attic of a house with loose fill insulation, Can You Use Loose Fill Insulation In Walls?

Can You Use Loose Fill Insulation In Walls?

You can undoubtedly use loose-fill insulation in walls. It's especially useful when you have already installed walls that you don't want to take down. For example, maybe you have an older home that's poorly insulated. You can improve the situation with loose-fill insulation and not tear down the walls.

When most people think of insulation, they picture batt insulation. This is the kind you see at home improvement stores. It is available in pre-cut standard sizes. It may come with or without an attached facing.

Loose-fill is precisely what it sounds like. It is smaller clumps of insulation that fill in the cavity or wall space.

If you still don't understand the difference, compare it to a pillow. Loose-fill is like stuffing the pillow with bean bag filling. Batt insulation is more like using foam padding.

Blown-in insulation on the attic

Loose-fill is typically made from cellulose, rock wool, or fiberglass. Loose-fill insulation offers better sealing for the home. It provides a tighter fill. It takes about 10-12 inches of loose fill to offer an R-value of 38.

While adding loose-fill insulation to the walls is possible, it takes special equipment to do it correctly. For this reason, the average DIYer will still need to hire a professional. On the other hand, Batt insulation is easy for an amateur to work with.

It's worth noting that some people do perform their own installation. In these cases, the loose-fill insulation is generally spotty and unevenly applied. The success, and subsequent R-value, vary wildly from one case to another.

It's the cheapest method and better than nothing. However, hiring a professional allows a "dense-packed" approach. This provides better insulation results. It costs more, but you get what you pay for in some cases.

How Do You Install Loose Fill Insulation In Walls?

Installing loose-fill insulation in walls is done with a blower machine. First, you drill a small hole in the top and bottom of the wall cavity. Then, you blow the insulation to fill the cavity.

Worker using a blower to applying insulation on the wall


It's tricky because you can't see inside the wall to know how good of a job you're doing. Even if you could, the tools just aren't the same for amateurs. You can rent lower-grade blower machines. But they don't fill with the same density that professional equipment does.

This is why, when you try a DIY approach, you just can't get the same results that a contractor can. You can save some money upfront. However, you may find that your heating bills do not improve. Your insulation may not be much better than it was.

Does Loose Fill Insulation Need A Vapor Barrier?

In most cases, loose-fill insulation does not need a vapor barrier. However, you may want to be cautious about adding it to a brick or concrete wall without one. These building materials are moisture permeable.

However, even considering this, cellulose has the ability to manage moisture. It's particularly effective at this when it's dense-packed. This means a density greater than 3.2 pounds per cubic foot.

And here is another excellent reason to hire a contractor. Their tools can provide this level of dense-packed installation.

Loose fill insulation in the attic

When installed this way, the Cellulose Insulation Manufacturer's Association does not recommend using a vapor barrier in most cases. Exceptions may be for very damp areas, such as in a room that houses an indoor pool. Brick and concrete walls in very cold climates may, similarly, get too damp.

Keep in mind that not all loose-fill is made with cellulose. If you know that you don't have a vapor barrier and want to avoid adding one, stick to cellulose. Do not pick blown-in fiberglass. Fiberglass does require a vapor barrier.

It's also worth noting that you'll want to know your local building codes. Cellulose may not need a vapor barrier, but the codes may still require one. Be sure to check with your local authority. Make sure that you are permitted to install insulation without a vapor barrier.

How Long Does Loose Fill Insulation Last?

When you ask how long loose-fill insulation lasts, you'll see a wide range of claims. Some say 100 years; others say 30. So what's the deal?

The difference between these two numbers is that one is possible while the other is realistic. Technically, loose-fill can last as long as 100 years. This is according to the International Association of Certified Home Inspectors.

But 100 years means in the absolute best conditions and with the best care. And, of course, the best conditions rarely occur.

A lot can shorten the lifespan of your loose-fill insulation. Water damage, pests, mold, or mildew are just a few examples.

Pouring recycled paper insulation

For these reasons, the average homeowner may get closer to 25-30 years instead. Sometimes, they may also replace it with something they feel is more efficient.

One advantage of loose-fill is that you can add more without removing any. If it has begun to settle, you don't have to start over to keep your home warm. Instead, you can blow in another layer to fill in any gaps.

Of course, this only helps if the insulation is still in good shape. If there are signs of mold or damage, remove and replace it all.

Is Loose Fill Or Batt Insulation Better?

Whether loose-fill or batt insulation is better depends. The needs of your project can decide which is right for you. Some pros of each include:

Batt Insulation

  • Easy for a homeowner to install themselves.
  • Convenient if you have not yet put up drywall and the wall is not already built.
  • Fairly consistent insulating properties through all areas of the wall or cavity.
  • It can be bought with a vapor barrier.

Loose-Fill Insulation

  • Easier to fit in irregular areas where batt insulation does not, such as around a chimney.
  • When properly installed by a professional, it can offer better insulation than batts.
  • Easy to add to an already existing wall. You won't have to demolish everything.
  • Loose-fill cellulose is one of the most eco-friendly types of insulation.
  • Easier to add new insulation on top of old. This can increase the overall insulating capabilities.

So is loose-fill or batt insulation better? It depends on your situation, of course. Batt insulation is cheap and easy. But loose-fill insulation offers a superior product in most cases.

If you can afford it, have loose-fill insulation installed properly. You'll find that the results are better.

Of course, it's also better to have well-done batt insulation than poorly done loose-fill. If money and time are an object, commit yourself to the insulation you can do well. Any good insulation installed correctly is still better than nothing. And poorly installed insulation is just a hair away from "nothing," no matter the material.

In Conclusion

An attic of a house with loose fill insulation, Can You Use Loose Fill Insulation In Walls?

If you have an old, poorly insulated wall, it's easier to fix than you might think. You don't have to tear down the entire wall. Instead, you can use loose-fill insulation. Just add it behind the wall with a blower, through a small hole.

Some people rent blower machines to do this job. But you can't make it as dense this way, which helps stop moisture and keep in the heat. You can get a dense layer with the right professional tools. For this reason, it's better to hire a contractor.

Using a pro costs more, of course. But it will pay for itself with your new low heating bills. Not to mention a properly insulated wall!

If you enjoyed this, try these articles next:

Can You Mix Fiberglass And Cellulose Insulation?

How Thick Should Cellulose Insulation Be In An Attic?

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