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What Are the Best Tips for DIY Wall Insulation?

Alex Paul
Alex Paul

There are a number of do-it-yourself (DIY) wall insulation tips that can make the process easier and more effective. Firstly, choosing between external and internal insulation is an important step, because both have advantages and disadvantages. It’s also important to choose the best material for the job, with fiberglass, spray foam and cellulose being the most common materials. Other tips for DIY wall insulation include understanding the potential safety problems and preventing the buildup of moisture.

The practicalities of external and internal wall insulation are very different. External insulation is more expensive but is the preferred option of many people, because it doesn’t require the interior of a home to be redecorated. If redecoration isn’t an issue, however, then internal insulation could be considered, because it is usually much easier to install. External DIY wall insulation is only recommended for people with strong DIY skills, because it can be a difficult job requiring a number of complex materials.

A closeup of spray foam insulation.
A closeup of spray foam insulation.

In the modern home of the early 21st century, fiberglass insulation remains the most common type of insulation in both walls and attics. The strength of the insulation, or how effective it is at preventing heat transfer, is called the R-value. Materials with higher R-values provide greater insulation but are usually more expensive. Other materials, such as spray foam and cellulose, also are often used for DIY wall insulation, but vary in R-value and cost. Rigid foam is usually only used for exterior insulation.

A roll of mineral wool insulation.
A roll of mineral wool insulation.

Before installing DIY wall insulation, it’s important to understand the potential safety concerns. It’s essential to wear a mask at all times, especially when working with fiberglass. This is to prevent sharp particles from entering the lungs. Protective clothing covering other parts of the body also helps to reduce the chance of injury. When removing existing insulation, it’s also important to dispose of it correctly to prevent damaging pollutants from being released into the environment.

A common mistake in DIY wall insulation is to block vents with insulating material. This should be avoided, because reduced air flow causes the buildup of moisture, resulting in damage to the insulation and allowing mold to grow. Installing a moisture barrier, which helps to reduce the amount of condensation buildup on the surfaces of the insulation, also is a good idea. When installing fiberglass DIY insulation, it's also good to avoid crushing as much as possible into the space available, because this changes the structure of the material and makes it less effective.

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Discussion Comments


@Izzy78 - You can definitely use the same type of insulation for walls as you can for an attic. More than likely you'll want to choose something with a little lower R value, though, since the walls don't let as much heat escape, and attic insulation can be pretty thick.

I've replaced insulation in a couple of houses, and it's not as hard as it sounds. What a lot of people do is just use a staple gun or staple hammer and tack down an edge of the insulation to a stud to stop it from falling out. For wires, I usually just go behind them if I can, but outlets you might need to cut out a notch or something.

Doing the insulation installation on your own should save you a good bit of money. Just remember to wear the proper clothing and eye protection. As you probably experienced with the attic, touching the fiberglass isn't a pleasant experience.


Can you use the same type of rolled fiberglass insulation for your walls as you use for your attic? We replaced that a few years ago, and it was pretty easy to do. It was been very effective so far, and I'd like a similar experience with the wall insulation.

Also, what do you do when you run into things like electrical outlets and wires and things like that? Do you just cut the insulation and start again below it, or just lay the insulation over the top? Also, once the insulation is in place, how do you stop it from falling out before you have the drywall over the top of it?

We have my father building a new room onto our house, and we'd like to be able to do as much of the work ourselves as possible.


@jmc88 - I'm not sure if they typically use blown insulation outdoors or not. I would probably stick with foam board, anyway. It should be less expensive and easier to install. If you are thinking about doing this all yourself, foam board will be about the only way to go, since you have to hire someone for blown insulation.

I have never installed insulation over a whole house, but my brother and I did it when he built his garage. It's pretty simple if you have a moderate level of DIY experience. You're basically just drilling in screws.

As far as R values go, that really just depends on your location and desired level of insulation. Warmer places typically need lower R values and vice versa. Just check with your local hardware store, and I'm sure they can help you out.


What are some of the different types of external insulation materials besides foam boards? I know blown insulation is becoming a lot more common lately. Can you use that, or is that mostly an internal thing, too?

We are looking to have our house resided in the next year or so, and it would probably be a good idea to see about upgrading the insulation while we are at it. The house definitely has the same insulation now as it did when we moved in 10 years ago, and there's no telling how long it was there before that.

What does everyone think is the best type of insulation for the price, and is there any specific R value that I should be looking for?

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    • A closeup of spray foam insulation.
      By: PiLensPhoto
      A closeup of spray foam insulation.
    • A roll of mineral wool insulation.
      By: brozova
      A roll of mineral wool insulation.