Yes, you can mix different types of insulation, but you must do it correctly to avoid moisture issues, reduced efficiency, or safety hazards. The most important rule is to layer insulations rather than blending them together, and never mix two types within the exact same wall or stud cavity.
In fact, a thin seal coat of spray insulation followed by rockwool or fiberglass is an approved method. As long as the rockwool and fiberglass are properly installed, that should be fine. The one thing I would avoid is mixing and matching the rockwool and fiberglass in the same bay.
In the majority of cases, removal of old insulation is NOT necessary before adding new. Nonetheless, we recommend getting a comprehensive assessment by a home insulation professional to make sure there are no issues that could adversely affect the efficiency of the new material.
Yes, it matters significantly based on your specific application and climate. Facing acts as a vapor retarder to block moisture. Using the wrong type can trap moisture inside your walls, leading to dangerous mold, mildew, and rotting wood.
Technically yes, but practically no, you should not install standard R-19 fiberglass batts into 2x4 walls. R-19 batts are designed for 2x6 walls (which are 5.5 inches deep), meaning they are too thick for a 2x4 cavity (which is only 3.5 inches deep).
You cannot and should not install standard R-30 insulation directly into a 2x4 wall. R-30 fiberglass and mineral wool batts are roughly 7 to 8 inches thick, while a 2x4 wall cavity is only 3.5 inches deep. Forcing R-30 into a 2x4 wall crushes the insulation, ruining its thermal performance and potentially causing drywall to bulge.
It's recommended to leave an air gap insulation of at least 25mm or 1 inch for the walls and ceilings. This should be enough to allow for ventilation and prevent moisture buildup. The same rule may be applied when using foil insulation. On roofs, the air gap should be larger, typically around 50mm or 2 inches.
Yes, mice absolutely love blown-in fiberglass insulation. It provides a soft, warm, and highly structured environment for nesting, tunneling, and breeding.
Insulation materials themselves generally maintain a consistent baseline price year-round, but late fall and winter (November through February) are typically the cheapest times to hire contractors for installation. During these off-peak months, demand drops and contractors are more likely to offer 10% to 25% discounts to secure work.
Existing walls can also be insulated with injection foam. Installing injection foam is similar to installing blown-in insulation in that we drill small holes into the drywall. But injection foam is different from loose fill insulation.
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.
To insulate a 1,000-square-foot space, you will typically need 20 to 45 bags of blown-in insulation. The exact amount depends heavily on whether you are using cellulose or fiberglass, and the depth (R-value) required for your climate.
Yes, rodents absolutely love foam board insulation. While it offers no nutritional value, the soft texture is incredibly easy for mice and rats to chew through. They shred it to build warm, insulated nests, and use the boards to create extensive, hidden tunnel systems within your walls.
Closed cell spray foam is rigid once set. It is a better thermal insulator and was previously sold to stabilise failing roofs. But if it has been used inappropriately or installed poorly, it might put stress on timbers, restrict air circulation and put them at risk of decaying.
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+.
No, you should never put vapor barriers on both sides of insulation. A double vapor barrier essentially creates a moisture trap, sealing any water inside the wall cavity and leading to rot, mold, and structural damage over time.
The cheapest and most effective insulation overall is blown-in cellulose for attics and fiberglass batts for open walls. Both materials provide excellent thermal resistance (R-value) for their price and are widely accessible for both DIYers and professionals.
Home insulation doesn't have an “expiration date,” and the material doesn't “go bad” after a certain number of years have passed. Ultimately, the condition of the insulation and its performance are more important factors than age when deciding whether to upgrade or replace insulation.
Insulating a 1,000-square-foot space costs between $1,000 and $5,000 fully installed, or about $150 to $1,000 if you only buy the materials to do it yourself. Prices vary significantly depending on the material, labor in your area, and whether you are insulating a roof, wall, or crawl space.
The Amish control mice through non-chemical, self-sustaining methods, relying on active trapping, natural scent repellents, and structural exclusion. Rather than using commercial poisons, they focus on physical barriers and natural predators to keep rodent populations in check.
People remove spray foam insulation primarily because poor installation or improper use traps moisture. This hidden condensation causes severe wood rot, mold growth, and pest infestations. Additionally, the inflexible barrier can strain roof timbers and prevent surveyors from assessing the home's structural condition, which often leads mortgage lenders to reject loans.
Closed-cell spray foam and rigid foam board are hard, unattractive to rodents, and double as air barriers. Mineral wool is dense enough to discourage nesting. Fiberglass batts, especially in crawl spaces and attics, are essentially an open invitation.
Interior walls are frequently left uninsulated during construction because the energy efficiency benefits aren't as great as insulating exterior walls, floors and ceilings.
Don't Install Loft Boards Directly on Joists
This can compress the insulation and create stress on the plasterboard below. Raised Boards Are Best: Installing loft boards on raised supports or Loft Legs ensures that the insulation is left undisturbed, allowing it to work at its optimal level.
In basements, installing a vapor barrier on the interior wall in front of the insulation and behind the drywall will keep the basement temperature consistent and protect its contents from water vapor damage.