Best DIY attic insulation guide covers Fiberglass, Mineral Wool, Cotton, Cellulose, Spray Foam, Rigid, Radiant Barriers, Structural video and text instructions.

Most homeowners ignore the importance of attic insulation until they receive their energy bills at the end of the month. If you don’t want to deal with excessive payments, consider these best DIY attic insulation guide for your home.

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Fiberglass batts are the most common options in attic insulation. These are thick sheets made of fiberglass, sand, and recycled material. Almost like cotton candy, but do not be fooled by its appearance. Fiberglass batts are ideal for spacious attics. Durability is a crucial feature of fiberglass batts.

The process of installing or applying fiberglass batts is easy. Measure the designated spaces, cut the batts, and you’re good to go. Make sure to do this as accurately as possible. And avoid blocking the vents, so your attic has enough airflow.

Pros of Fiberglass Batts Attic Insulation

  • Moisture Resistant

  • Fiberglass batts doesn’t attract moisture. Making your house safe from mold, mildew, and other moisture-related nuisances.

  • Fire Resistant

  • Sand, fiberglass, and the recycled materials used for these batts are non-combustible. It does not matter how hot it gets; these things will never light up.

  • Easy to Install

  • Among all the other options, fiberglass batts are the easiest to install. Get an appropriate measurement, fit them on the spaces, and that’s it. No extra effort and fancy tools are required.

Cons of Fiberglass Batts Attic Insulation

  • Less Effective

  • Fiberglass batts tend to be less effective compared with other insulation types. Many professionals do not recommend fiberglass batts. People often resort to these things because of the ease of installation.

  • Requires a Lot

  • If you are considering fiberglass batts, buy a lot. If you don’t use enough, you won’t get the right amount of insulation—kind of a pain in the wallet.

How to Insulate Attic using Fiberglass Batts

  • Step 01

    Measure the length and width of the joist bays, as shown in the video.

  • Step 02

    Cut the fiberglass batts into pieces.

  • Step 03

    Fill the eaves with fiberglass batts. Make sure to keep two inches gap between the vents for sufficient airflow.

  • Step 04

    Use fiberglass batts with vapor retarders on direct ceilings. Use unfaced batts on the bays that already have loose-filled insulation.

  • Step 05

    Add another layer of insulation on top of the second layer for improved R-Value.

  • Step 06

    Remove a board and add blown-in fiberglass insulation under the floor. This prevents dust from going around the room.

Next to fiberglass batts are mineral or stone wool batts. Made of volcanic rock, blast furnace slag, and coke from coal. Much like other batts used for insulation, they have the consistency of cotton candy. This makes them soft and easy to install around the attic.

They are fire-resistant, water repellant, and they can block noise. You can easily cut these things with a bread knife. That means you can easily adjust their sizes to fill your attic bays.

Pros of Mineral/Stone Wool Batts Attic Insulation

  • Fire Resistant

  • Mineral wool batts are ideal for every home because of this trait. No matter how hard you try to burn it, it will never ignite. The texture and look will naturally change, though.

  • Water Repellent

    This insulation type has the same effect as a waxed windshield. When you pour water on it, the liquid naturally flows downwards. This feature makes it perfect for attic insulation, especially in stormy areas.

  • Easy to Shape

    Despite the rock-hard materials, mineral wool batts are easy to shape. They are fluffy and stacked, making them easy to stuff on tight spaces. It is advised to use a bread knife when cutting these things. The serrated edges make it easier to cut through the insulation.

  • Noise Resistant

    Having mineral wool batts for insulation means more noise resistance. The compressed batts are perfect for blocking any external noise. Whether it’s birds or squirrels or raccoon on your roof, you won’t be disturbed by their presence.

Cons of Mineral/Stone Wool Batts Attic Insulation

  • Harmful Materials

  • Volcanic rock, blast furnace slag, and coke are unfriendly substances. They are quite dangerous (possibly cancerous) for our bodies. If you are installing this insulation type, make sure to wear protective gear. Avoid inhaling it as much as possible to avoid complications.

How to Insulate Attic using Mineral/Stone Wool Batts

  • Step 01

    Watch your step when you are going into the attic.

  • Step 02

    Check the existing insulation between the joists or rafters.

  • Step 03

    Lay the new insulation on top (perpendicular) of the old insulation. This helps to improve the R-Value of the loft. It will also avoid thermal bridging, the transfer of heat or cold through substantial items. More insulation means improved temperature maintenance in the house.

  • Step 04

    Start on the corners and sides first.

  • Step 05

    Shape your mineral wool batts for unexpected obstacles. You can use a bread knife for this.

  • Step 06

    Fill the room with batts until it reaches the required R-Value.

Cotton or Denim Batts is one of the softest items in this list. They are made of recycled denim or blue jeans. Their compressed structure makes it easy to install between rafters and bays. Make sure to wear a dust mask when using these because they are dusty.

Despite the compressed structure, some of these are thinner than most insulators. You have to use a lot to get enough insulation. Suitable for the attic’s walls and ceilings. Avoid pushing the insulation in and let them stick out to ensure effectiveness.

Pros of Cotton/Denim Batts Attic Insulation

  • Environmentally Friendly

  • Denim batts are the most environmentally friendly option out there. They are composed of recycled jeans, avoiding the risk of physical ailments.

  • Soft Texture

  • This type of attic insulation is more delicate than the others since it is made of cotton/denim. You won’t encounter problems in the installation process. You can easily fit them in tight spaces such as joist bays and ceilings.

  • Easy to Shape

  • Much like other batts, denim insulation is easy to shape. You can use any working knife to cut these. That also makes them ideal for insulating new houses.

Cons of Cotton/Denim Batts Attic Insulation

  • Expensive

  • Because of their materials, denim batts are usually costly. This is one of the reasons why homeowners consider other options. If you really want this insulation in your attic, you need to save up.

  • Dusty

  • Denim batts are more dusty compared with the other materials. If you are planning to use these, make sure to wear protective gear. It is always better to be safe than sorry.

How to Insulate Attic using Cotton/Denim Batts

  • Step 01

    Wear a dust mask and goggles (when working overhead).

  • Step 02

    Do not push in the insulation. It negates the R-Value of the denim batts.

  • Step 03

    Start doing the walls first.

  • Step 04

    Keep the batts sticking out a little bit for maximum insulation.

  • Step 05

    Cut around the openings to limit airflow.

  • Step 06

    Add netting to the ceiling insulation. Use a high-grade staple gun for application.

  • Step 07

    Make sure that the insulation will fill the cavities fully.

A special device blows in cellulose. The cellulose is made of shredded newspaper. These are tedious things since they release a lot of dust.

Since cellulose has cheaper materials, it is considered cost-effective. They can fill your attic’s gaps quickly and effectively. Also, the material is mixed with a fire-retardant chemical. It also keeps pests and rodents away from your house.

Pros of Blown-in Cellulose Attic Insulation

  • Perfect for Tight Spaces

  • You can spray them on until the attic bays are filled with insulation. Wear masks when you are doing this. Cellulose tends to be a dusty work buddy.

  • Cheaper Than Most Insulation Types

  • Cellulose is primarily made of shredded newspaper, making it cheaper. If you are planning to keep a tight budget, this is an ideal choice.

  • Can Be Used as Base Insulation

  • Most professionals blow in cellulose first before stuffing the bays with batts. They are useful as base insulation, especially in tight corners. If you want better results, you could consider this process.

Cons of Blown-in Cellulose Attic Insulation

  • Too Heavy for Some Structures

  • The compression of blown-in cellulose tends to be heavy for some attics. Before using these, make sure to get your house inspected first. It would also help if you’d let professionals handle the insulation themselves.

  • Requires a Vapor Barrier

  • As mentioned before, cellulose is made of shredded newspaper. Naturally, it is vulnerable to moisture. When using these, you should place moisture barriers first to help prevent moisture from seeping into the insulation.

How to Insulate Attic using Blown-in Cellulose

  • Step 01

    Wear protective gear. Cellulose is dirty and dusty.

  • Step 02

    Cut the package in half to expose the insulation.

  • Step 03

    Break off chunks and let it fall into the blower.

  • Step 04

    Go to the attic and start blowing in the cellulose.

  • Step 05

    Get it all the way on the ceiling. Spread it evenly, and then work on the rest of the attic.

Aside from batts, fiberglass also comes in a loose-fill option. You can use it for the blown-in insulation method. If you are not fond of using batts, then blown-in fiberglass could work for you.

This method is one of the oldest insulation types in the book. Like cellulose, loose-fill fiberglass is filled in large bags that you can order. You can use a blowing machine to spread these throughout your attic. It is also dusty, so wear protective masks and goggles when doing this.

Pros of Blown-in/Loose-Fill Fiberglass Attic Insulation

  • Perfect for Filling Tight Cracks

  • Any type of blown-in insulation is right for tight spaces. Of course, that means loose-fill fiberglass is no different. If you have small joist bays and walls, you can easily use this.

  • Cheaper Than Other Options

  • Loose-fill fiberglass may be the most affordable insulation you will find. That is because it is easy to manufacture and manipulate. You can buy it in packages, making it cost-effective.

  • Same Materials as Fiberglass Batts

  • This type of insulation has the same materials as its batt version. If you avoid certain things for fiberglass batts, apply those to the loose-filled type.

Foam board or rigid foam insulation is a bit different from the others. Just as the name suggests, these are rigid squares of foam. That means they are durable, dependable, and of course, effective. Most modern houses have this kind of insulation within them.

Unlike other insulation types, this one is installed before the house is built. They are placed within the walls just before the drywall or plaster is applied. You can use table saws for bigger foams and utility knives for smaller cuts. Usually, this type of insulation is run by a team.

Pros of Foam Board or Rigid Foam Attic Insulation

  • Durable

  • Rigid foam boards are durable to withstand moisture and heat. This makes them reliable options for insulation. Aside from that, they are installed within the walls. That placement alone improves the strength of your house.

  • Easy Manipulation

  • Shaping these things is not that hard either. You can use a table saw for the bigger portions of rigid foam. For the smaller cuts, you can use utility knives. Make sure to use tapes when installing them so the air won’t seep in.

  • Effective

  • Since foam boards are installed within the walls, you can be sure of their effectiveness. They will hold the temperature without compromising your home’s appearance.

Cons of Foam Board or Rigid Foam Attic Insulation

  • Expensive

  • Because of their material and construction, foam boards are quite expensive. Making it the least favorite option for attic insulation. If you are getting these, be prepared to burn some real cash.

  • Installed During Construction

  • The biggest downside of rigid foam insulation is the installation process. You cannot install foam boards on a finished house. To do that, you will have to tear down the walls first and then rebuild. That’s why these are applied during house construction.

How to Install Foam Board or Rigid Foam Attic Insulation

  • Step 01

    Measure the area on the house wall as shown in the video

  • Step 02

    Cut the required measurements for the rigid foam.

  • Step 03

    Caulk the places where the foam will be applied.

  • Step 04

    Accurately place the rigid foam by the walls.

  • Step 05

    Apply tape on the sides. This will hold the foam firmly and act as an air and moisture seal.

  • Step 06

    Tape down the layers.

Structural Insulated Panels or SIPs are mostly used for roofs. Also effective for attic spaces. They can replace rafters and studs in the house frame. If you have spacious attics, this is an excellent option for insulation.

SIPs have compressed materials that are perfect for sealing air. This also makes them reliable for soundproofing. Like rigid foams, these panels are quite pricey. You also need to install them during house construction.

Pros of Structural Insulated Panels (or SIPs) Attic Insulation

  • Noise Reduction

  • SIPs are manufactured in an airtight manner. This means that you’ll have noise reduction when you place them on your walls. This is useful if you’re living in a lively neighborhood.

  • Compressed Manufacturing

  • SIPs are effective because of their compressed manufacturing. This ensures that the air is sealed within the attic. By having these within your walls, your attic will have increased R-Value.

  • Durable Structure

  • Most professionals prefer this type of attic insulation. The reason for that is because of their stable build. That is also probably why they are hard to install. SIPs are quite heavy, and they are sometimes bulky.

Cons of Structural Insulated Panels (or SIPs) Attic Insulation

  • Pricey

  • SIPs are pricey because of their high-grade materials and manufacturing. Have a moderate budget if you are planning to use these.

  • Installed in Construction Process

  • Like rigid foams, SIPs are also installed during the construction process.

How to Install Structural Insulated Panels (or SIPs) Attic Insulation

  • Step 01

    Follow the video and apply expanding foam sealants before assembling SIPs.

  • Step 02

    Use 1 & 1/2-inch thick bottom plates to interlock with the SIPs.

  • Step 03

    Use OSB splines to connect adjacent panels.

  • Step 04

    Top each wall with 1 & 1/2-inch lumber and a cap plate.

  • Step 05

    For door and window frames, you can line them in the same way. Measure first for accurate alignments.

  • Step 06

    Cut SIPs depending on your windows’ structure. This ensures maximum efficiency.

  • Step 07

    Use a hot knife to reestablish recessed edges.

  • Step 08

    Use a beam cutter to cut each panel in their specific length, width, and angles.

Radiant barrier attic insulation is perfect for hotter areas. If you live in stormy weather like Florida and Hot part of the states like Texas, this is good for your home. Radiant barriers block the heat and moisture coming into your roof.

The primary purpose of radiant barriers is to keep your house cool. They do this by reflecting the heat away from your roof. Primarily made of reflective materials, among them are aluminum foils. If you want to reduce your cooling costs, get your attic insulated with radiant barriers.

Pros of Radiant Barriers for Attic Insulation

  • Affordable

  • Radiant barriers are probably the most affordable insulation you will find. They are thin yet useful. Besides, their purpose is to reflect heat away from the house. That is easier to achieve rather than sealing heat.

  • Efficient

  • Radiant barriers insulation is also the most efficient. Especially suitable for hot, humid weather.

  • Cost-Effective

  • ou will definitely get your money’s worth with radiant barriers. They are inexpensive and practical.

Cons of Radiant Barriers for Attic Insulation

  • Vulnerable to Dust

  • One of the downsides of radiant barriers is their vulnerability to dust/dirt. Attracting dirt compromises their effectiveness. Resulting in faster depreciation.

  • Only Effective on Radiant Heat

  • Radiant barriers are effective when reflecting heat away from the house. For conductive heat within, not so much. That’s why you’ll need thermal insulation inside your home as well.

How to Install Radiant Barriers for Attic Insulation

  • Step 01

    Do not lay the barrier on top of the current attic insulation.

  • Step 02

    Attach the barrier insulation to the rafters.

  • Step 03

    Do not directly attach the radiant barrier on the decking. Maintain an air gap for the air to flow out of the vent.

Spray foam insulation is one of the messiest yet most effective options out there. This is considered as the best insulator by most professionals. Spray foam is made of delicate materials. You may need experts to help with installing the spray foam insulator.

This insulation type has unique characteristics compared with the others. It’s a foamy substance that hardens eventually. It’s an effective air sealant for your attic. Also proves to be a good noise barrier in certain circumstances.

Pros of Spray Foam for Attic Insulation

  • Airtight Sealing

  • Spray foam insulation hardens over time, sealing any air hole in place. That is the main reason why this is considered as the best insulation.

  • Anti-Moisture

  • Unlike cellulose, spray foam is 100% impervious to moisture. It will never get wet, and it will stay that way.

  • Sound Barrier

  • It also has decent soundproofing properties. If you are living in an industrial or college area, it can help you deal with the noise.

  • Strengthens the Building’s Structure

  • Another good thing about the spray foam is durability. Aside from being an insulator, it can provide support to your house structure.

Cons of Spray Foam for Attic Insulation

  • Non-Removable

  • One of the most significant downsides of spray foam is its non remove ability. It’s not a temporary solution at all.

  • Expensive

  • Spray foam is the most costly insulation type out there. If you are looking for budget-friendly options, you may want to skip this one.

How to Install Spray Foam for Attic Insulation

  • Step 01

    Open-cell foam is applied much thicker (up to 7 inches). Closed-cell foam is applied approximately 2-3 inches.

  • Step 02

    Apply the spray foam to the bottom of the roof deck.

  • Step 03

    Apply a vapor barrier paint on the insulation’s bottom part.

Last Words

Attic insulation makes your home comfortable in many ways. It helps in saving energy too. My guide on best DIY attic insulation enables you to get the job done. Comment below with your requirements, and I’ll suggest the best suitable insulation method for you.


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