You need faced insulation if it is your home's very first layer against the ceiling drywall, as the facing acts as a vapor barrier. You need unfaced insulation if you are adding a top-up layer over existing insulation, or if you already have a separate vapor barrier installed.
Attic Applications
In most attics, use faced insulation for the initial installation between joists. The facing should face down toward the living space below. However, if you're adding insulation on top of existing faced insulation, always use unfaced to prevent moisture trapping.
In an attic, the paper or foil facing (vapor barrier) should always face downward against the warm ceiling of the living space. The pink or yellow fiberglass should be visible when you are standing in the attic, and the paper side should be touching the drywall/ceiling below.
Choose faced insulation if you need to control moisture, such as in exterior walls, basements, or attics. Choose unfaced insulation for interior rooms, soundproofing, or when adding a second layer of insulation over an existing barrier.
Avoid faced insulation when adding to existing insulation, insulating interior walls, or working in spaces with existing vapor barriers. Using faced insulation in these situations creates a "double vapor barrier" that traps moisture, leading to severe mold and wood rot.
The least toxic attic insulation materials are natural, plant-based, or mineral products with low or zero VOC (Volatile Organic Compound) emissions, no formaldehyde binders, and no irritating glass fibers. The top eco-friendly and non-toxic options for attics include cellulose, mineral wool, cotton (denim), and sheep's wool.
You generally do not need to remove old attic insulation before adding new insulation. It is usually more cost-effective to leave the old layer in place and simply blow or roll new insulation on top, provided the existing material is in good condition and dry.
The "best" attic insulation depends on your budget, whether your attic is ventilated, and your climate. Generally, blown-in cellulose is the top pick for open, ventilated attics, while spray foam is best for creating a conditioned, unvented attic to maximize energy efficiency.
Unfaced insulation is generally cheaper than faced insulation, as it lacks the extra vapor retarder material (kraft paper or foil).
Yes, mice absolutely love blown-in fiberglass insulation. It provides a soft, warm, and highly structured environment for nesting, tunneling, and breeding.
When insulating an attic, never cover your soffit vents with insulation, as this blocks necessary airflow and leads to moisture and mold problems. Furthermore, never skip the air-sealing process or bury standard, non-IC-rated light fixtures under insulation, as both mistakes pose severe safety hazards.
The "7-and-7" rule refers to the minimum building code standards required to legally convert an attic into a habitable, livable space. It dictates that the room must have at least 7 feet of ceiling height across at least 50% of the floor space, and a minimum total floor area of 70 square feet.
What's the best loft insulation thickness? The UK government recommend a minimum insulation thickness of 270mm although we tell people that 100mm should be the absolute minimum.
Yes, you can use faced insulation in an attic, but only for first-time installations. The facing (kraft paper) acts as a vapor barrier and must always be installed facing downward, toward the heated/air-conditioned living space.
Unfaced insulation is a highly versatile, budget-friendly option without an attached vapor barrier (like paper or foil). It is primarily used for interior walls, insulating over existing layers, or rooms where you do not need to block moisture.
Insulating a 2,000 sq. ft. attic costs between $2,000 and $9,000 on average, depending on the material and labor needed. Blown-in fiberglass or cellulose usually runs $2,000 to $4,000, while premium spray foam costs $8,000 to $18,000+.
Whether you need faced or unfaced insulation depends on what is already in your attic and your climate. Use unfaced if you are adding new insulation over existing layers. Use faced for a brand-new installation (with the facing down toward the ceiling) to prevent moisture from condensing in your attic.
The healthiest home insulations are natural, zero-VOC materials like sheep's wool, hemp, cellulose, and cork. Unlike conventional options like fiberglass or spray foam, they do not off-gas toxic chemicals or release respiratory-irritating dust, resulting in significantly better indoor air quality.
Faced insulation has a vapor retarder to help control moisture, making it ideal for exterior walls and attic ceilings. Unfaced insulation is a more versatile option often used in interior walls and between floors where moisture control isn't as critical.
Excess insulation in the attic can make a house too tightly sealed and block vents. If airflow is blocked, moisture can't escape. If moisture accumulates in the attic and comes into contact with warm air, that can allow mold to grow, which can result in serious respiratory problems in people.
Yes, mice can chew through and tunnel in rockwool (mineral wool) insulation. While rockwool is denser, fireproof, and doesn't provide nutritional value, its loose fibers and coarse texture actually make it an attractive material for mice to gather and shape into nests.
Banks and mortgage lenders often dislike or outright reject homes with spray foam insulation because it can trap moisture against roof timbers, leading to hidden wood rot, mold, and structural decay. Additionally, the foam conceals the roof structure during valuations, making it impossible for surveyors to assess the roof's true condition.
You usually don't need to replace 20-year-old insulation just because of its age. Many types last 80 to 100 years. However, you should replace or upgrade it if you have settling, water or pest damage, or if you notice uneven room temperatures and rising energy bills.
The "7 and 7 rule" is a standard building code guideline for converting an attic into a legally habitable living space. It requires that the room must measure at least 7 feet in ceiling height over at least 50% of the usable space, and have a minimum of 70 square feet of total floor area.
Buyers often walk away from homes with spray foam insulation because it can cause major mortgage and insurance denials. The foam tightly seals roof spaces, trapping moisture, and covers up structural timbers. This makes it impossible for surveyors to inspect for hidden rot or damage, which can lead to catastrophic repair costs.