When it comes to insulating your attic, spray foam insulation is often hailed as the go-to solution for its remarkable ability to create an airtight seal and provide excellent thermal performance.
However, it’s not the only option available. In this article, we will explore a range of alternatives to spray foam insulation for your attic, each with its own set of advantages and considerations.
Whether you’re looking for cost-effective options, eco-friendly alternatives, or simply exploring different insulation methods, we’ve got you covered.
Join us as we delve into the world of attic insulation to discover the many choices at your disposal beyond the ubiquitous spray foam.
Textiles – Denim (Cotton Insulation)
There are less common alternatives to using spray foam insulation in your attic, like recycled denim insulation. Denim insulation has about the same R value as the more common blown in fiberglass or cellulose, but is safer to work with.
Denim insulation is also more environmentally friendly, and provides an R value similar to fiberglass batts.
Denim is made from recycled blue jeans, so the fibers are not as dangerous as fiberglass to touch or inhale. Denim is installed with compression, so no mechanical fasteners are needed. Denim insulation is made from cotton, so it will not cause irritation like fiberglass insulation can.
Denim costs about 10% more than fiberglass insulation because of the processes required to manufacture it. Denim insulation is treated with the same fire and mold retardants as fiberglass and cellulose loose fill insulation, making it both safe and effective.
Denim Insulation Pros:
- Denim insulation does not require mechanical fasteners. Denim insulation is much more dense than fiberglass batts, so careful measuring allows denim insulation to stay in place using friction.
- Denim insulation does not require the use of safety gear like gloves, goggles, and respirators.
- Denim insulation resists compacting over time, maintaining its R value.
Denim Insulation Cons:
- During installation, denim insulation is not as easy to cut as fiberglass batts. Denim should be measured carefully because it must fit snugly in the opening.
- Denim is expensive compared to fiberglass batts because of the manufacturing processes required to make it.
- Denim insulation is usually special order, so you must be very accurate in your measurements to avoid running out or wasting additional material.
- Denim insulation will absorb moisture very easily. If denim insulation becomes wet it loses its insulative properties and becomes a conductor.
Mineral Wool Insulation
Mineral wool, also known as rock wool, is an older form of attic insulation made from spun volcanic rock. Obviously, mineral wool is durable and will not burn or produce toxic VOCs, like spray foam insulation.
Mineral wool is an effective insulator, but no more so than fiberglass or cellulose, which are less expensive options.
Mineral Wool Insulation Pros:
- Mineral wool is easy to work with.
- Mineral wool is the most fire resistant form of insulation available.
- Mineral wool has excellent sound absorbing qualities
- Mineral wool insulation is available as loose fill or in rolls similar to fiberglass batts.
Mineral Wool Insulation Cons:
- In contrast to denim or cotton insulation, mineral wool fibers will irritate the skin, eyes, and lungs, so safety gear must be worn.
- Mineral wool costs about 25% more than comparable fiberglass or cellulose, but does not provide 25% more R value.
Cellulose
Cellulose is another form of recycled insulation made from recycled paper products. Cellulose provides a similar R value to both mineral wool, denim, and fiberglass of the same thickness. Cellulose is very affordable, DIY friendly, and easy to install in an attic.
Cellulose Insulation Pros:
- Cellulose insulation is very cost effective, especially when installed by a do-it-yourselfer.
- Cellulose has excellent fire and mold retardant properties.
- Cellulose is recyclable, making it environmentally friendly.
- Cellulose insulation can be installed in an attic in a matter of hours.
Cellulose Insulation Cons:
- Although cellulose is not as caustic to the skin and lungs as fiberglass or mineral wool, safety gear is still required to install it.
- Cellulose will compact under its own weight over time, so more is commonly added every few years to maintain the R value.
- Cellulose can get sucked into the attic vents, so attic baffles are critical to maintaining attic ventilation.
Loose Fill (Blown in) Fiberglass
Most homes built today use blown in loose fill fiberglass or cellulose as attic insulation. Loose fill fiberglass is cost effective, easy to install, and available everywhere. Loose fill fiberglass will not burn in the event of a fire and contains a moldicide to control mold and mildew.
Loose Fill Fiberglass Insulation Pros:
- Loose fill fiberglass insulation is quick and simple to install, even by a first time installer.
- Loose fill fiberglass is very lightweight and can be installed by one person.
- Loose fill fiberglass can be added as needed over time without damaging the attic.
- Due to its popularity, many retailers will supply the hopper (the machine used to pump fiberglass insulation) for free.
Loose Fill Fiberglass Insulation Cons:
- Loose fill fiberglass shards are dangerous to your eyes, skin, and lungs, so full safety gear (including a respirator) is required during installation.
- If disturbed, loose fill fiberglass insulation can become airborne and reduce attic ventilation by blocking the vents.
Styrofoam Sheets
Styrofoam sheets are great for insulating attics and wall voids due to their convenient shape and malleability. Styrofoam is cost effective and installs very easily with just a few hand tools. Styrofoam has an R value of about 3-5 per inch, depending on the manufacturer.
Styrofoam Insulation Pros:
- Easy and safe to work with.
- Styrofoam sheets are inexpensive and can be added later as needed. If budget concerns prevent adding all of the insulation at once, styrofoam attic insulation is a good choice.
- Styrofoam is very lightweight, so it adds no significant weight to your attic or the framing.
Styrofoam Insulation Cons:
- Styrofoam will burn and emit toxic fumes (VOCs).
- Styrofoam is not durable and must be protected from impacts, insects, and birds.
- Styrofoam requires mechanical fasteners to install, like staples, button caps nails, or adhesive.
Cork Insulation
Cork insulation offers an R value similar to styrofoam by volume and is very environmentally friendly. Perhaps surprisingly, cork is a sustainable form of insulation and completely renewable. Cork is harvested about every nine years without permanently damaging the tree, so the process can theoretically go on forever.
Cork insulation Pros:
- Damaging insects like termites will not eat cork insulation, nor will mice and rats.
- Cork offers very good sound absorption.
- Cork insulation is completely biodegradable.
- Cork has natural fire resistant properties.
Cork Insulation Cons:
- Because cork is a natural material, it expands and contracts with the temperature. Additional sealants like caulk and spray foam are often added to seal small gaps and cracks.
- Cork is expensive compared to more traditional forms of insulation. Compared to styrofoam insulation sheets, cork is about 30% more expensive to purchase.
- Cork will burn, although the VOCs emitted are not considered as harmful as with styrofoam sheets.
