Yes, you can use Kraft paper, but it acts as a vapor retarder, not a true vapor barrier. It allows a controlled, small amount of moisture to pass through, whereas a true barrier (like polyethylene plastic) blocks moisture entirely.
What Is Faced Insulation? Faced insulation is the kind with a built-in vapor barrier—usually a sheet of kraft paper or foil stuck to one side. That facing isn't just there to make it look pretty. It's doing a job: blocking moisture from sneaking through your walls, ceilings, or floors.
Materials such as rigid foam insulation, reinforced plastics, aluminum, and stainless steel are relatively resistant to water vapor diffusion. These types of vapor retarders are usually mechanically fastened and sealed at the joints.
Some kraft paper absorbs water rapidly, while other grades stay dry even in humid environments. This difference does not happen by chance. Manufacturers control water absorption height through fiber selection, pulping methods, papermaking parameters, surface treatments, and environmental conditions.
Advantages of Kraft-Faced Insulation
With stapling flanges, kraft-faced insulation is easy to install between studs or joists, making it ideal for both homeowners and contractors. The Kraft paper offers basic vapor retarding for most residential settings.
One of the main concerns of recycled paper insulation is the sensitivity to moisture. If installed incorrectly, it paves the way for mold or mildew issues. Oftentimes, the settling of this insulation might also reduce its effectiveness.
You can use plastic if you put polyethylene between your drywall and the wall studs. This way, you should get a tighter wall without trapping moisture inside the exterior walls. If you are framing out a below-grade basement, however, do not use plastic as a vapor barrier.
✨Trivia Answer✨ Kraft paper acts as a vapor barrier, protecting your home from moisture. 💡 Tip: Kraft-faced insulation should be installed with the paper side facing toward the living space.
Poor moisture and water resistance. The key drawback of kraft paper bags is that they should not come into contact with water. When kraft paper gets wet, it becomes soft, and the entire kraft paper bag loses its structural integrity.
Sometimes, humidity or dampness (water vapor) in the air can supply enough moisture for mold growth. Indoor relative humidity (RH) should be kept below 60 percent -- ideally between 30 percent and 50 percent, if possible.
DIY Vapor Barrier Installation
DIY installation can offer cost savings and the satisfaction of completing the job yourself. However, it requires a good understanding of your home's moisture control needs and the ability to properly seal the barrier to prevent leaks.
The need for a vapour barrier depends on factors such as wall construction, climate, and the materials used. Vapour barriers prevent moisture from penetrating walls and reaching the insulation, which could condense and cause mould, mildew, and structural damage.
Can mold grow under a vapor barrier? Yes. If moisture becomes trapped beneath an improperly sealed or damaged barrier, mold can grow on the ground or on organic materials underneath it. Proper installation and regular inspection are essential.
Don't Install a Vapor Barrier Over Pre-Existing Mold or Standing Water. Active mold and standing water require remediation before installation. A vapor barrier traps existing moisture — which accelerates mold growth and worsens water problems.
Luckily, the Kraft paper facing is easy to remove. Simply pull on the facing with one hand and use the other hand to push the batt or roll away from the facing. Then, you'll be able to proceed with the repair. Should you choose to install Kraft-faced insulation, here's a helpful video and guide.
Kraft paper is eco-friendly because it's derived from renewable natural resources—mainly wood pulp sourced from sustainably managed forests. Unlike plastic, which depends on petroleum-based inputs, kraft paper relies on trees that can be replanted and regrown, making it part of a renewable cycle.
Kraft paper is hygroscopic — meaning it naturally absorbs and releases moisture in response to surrounding air.
Uses of kraft paper
They are used for transport, packaging, wrapping or protection.
While natural kraft paper is absorbent, it can certainly be engineered to be leak-proof and waterproof through the application of various coatings and treatments. These advancements have made kraft paper boxes a highly functional and reliable packaging solution for a wide array of food products.
There are a wide number of materials available to create effective vapor barriers, including:
Kraft-faced insulation adds an asphalt-backed kraft paper to one side of the standard insulation roll. In addition to providing additional stability to the insulation roll for hanging, the kraft paper facing also acts as a vapor barrier that offers an extra layer of moisture migration protection.
Insulation materials are typically thick and fibrous. Common types include fiberglass, mineral wool, and foam. Vapor barriers, by contrast, are thin plastic sheets—usually polyethylene starting at 6 mil thickness.
Overall, fibreglass insulation is the cheapest and most effective insulation option available, making it a popular choice for homeowners and builders alike.
Polyethylene Sheathing: Best For Crawl Space Floors
The best solution for a vapor barrier on your floor is polyethylene sheathing. Many crawl spaces already have some plastic tarp laid on the ground. Not every plastic tarp can create a vapor barrier.
Generally, if the crawl space will be entered regularly for maintenance — or used for storage — start at 12 mil or thicker. The 6 mil minimum is inadequate on rocky or debris-covered floors. One of the strongest vapor and gas barriers available.