In most cases, you do not need to remove old insulation before adding new layers on top. However, removal is necessary if the existing material is water-damaged, moldy, heavily soiled by pests, or contains hazardous materials like vermiculite.
Installing new insulation over old is a viable option for keeping your home warm in the winter and cool in the summer. However, the current insulation must be in good condition. It's vital that a professional insulation technician inspect your current insulation before adding another layer.
No, pure fiberglass insulation does not contain asbestos. In fact, fiberglass was widely introduced as a safe alternative to replace asbestos. However, the paper backing, adhesives, or the surrounding duct-wrap materials on older fiberglass installations can sometimes contain asbestos.
Fiberglass particles typically stay in the lungs for a relatively short period, ranging from a few days to a few weeks. Unlike asbestos, modern fiberglass is engineered to dissolve or break down, allowing the body’s immune cells (macrophages) to digest and clear the fragments.
Short-term Exposure
The symptoms of irritation are often nonspecific, temporary, and may include itching, coughing, or wheezing. High levels of exposure to airborne fiberglass may aggravate existing asthma or bronchitis-like conditions.
No, fiberglass insulation should never be left uncovered. Why? Health Hazards: Exposed fiberglass can release fine particles and fibers into the air, which can cause respiratory irritation, skin rashes, and eye irritation.
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.
Frost King CF1 No Itch natural cotton insulation delivers multi-purpose insulating, cushioning, and noise-dampening benefits for home and professional projects. The soft, no-itch cotton material acts as a sound barrier and can be cut or ripped to fit pipes, ducts, vents, walls, and other irregular spaces.
Enhanced energy efficiency: New insulation can help reduce energy costs by improving your home's ability to mitigate thermal transfer. Indoor air quality: You can improve the air quality in your home by removing old insulation that may harbor mold, dust or allergens.
How age affects insulation performance: Older homes built in the 1970s or earlier need to have their insulation replaced, especially if the insulation hasn't been replaced since. Common types of insulation in older homes include old fibreglass batts, cellulose, rockwool, foil, sawdust, wool, and polyester.
A 30-minute exposure to asbestos is generally considered low-risk for developing diseases like mesothelioma or lung cancer, as these typically arise from long-term, chronic exposure. While no amount of asbestos is safe, a single brief incident is unlikely to cause disease, though the risk is never zero.
The only way to definitively confirm if your insulation contains asbestos is to have a sample analyzed by a certified laboratory. Because visual inspection is not 100% accurate, you should assume it contains asbestos and avoid disturbing it if your home was built before the late 1980s.
Cellulose Insulation
The typical lifespan is 20 to 30 years, with degradation beginning as early as 15 years after installation. As with other types of insulation, severe weather or outside interference can reduce the lifespan.
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.
Insulating a 2,000 sq ft house typically costs between $3,000 and $12,000 fully installed. Prices range from $1.50 to $6.00+ per square foot, largely depending on your material choice, whether you are retrofitting existing walls, and if old insulation needs removal.
Yes, mice absolutely love blown-in fiberglass insulation. It provides a soft, warm, and highly structured environment for nesting, tunneling, and breeding.
Yes, you can leave old insulation in place if it's in good condition and separate from the new area. However, in connected spaces like attics and knee walls, poor insulation in one area can reduce overall energy performance. Inspect both before proceeding.
Should I do the project myself or hire a contractor? If your attic is accessible and not too difficult to move around in, and you enjoy tackling bigger home improvement projects, attic insulating may be a good DIY project. Otherwise, consider finding a contractor to complete the project for you.
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.
The healthiest insulations for a house are natural, bio-based materials that offer excellent thermal performance without off-gassing toxic chemicals. The safest and most non-toxic options available are sheep's wool, hemp, cotton (denim), and cork.
Fibreglass: A Foe in Disguise
Regarded as a superhero of insulation materials, fibreglass is lauded for its cost-effectiveness, fire resistance, and thermal efficiency. Yet, it has a small drawback. Its minute glass fibres, when dislodged, can lodge into skin, causing an irritating itch or even slight skin damage.
Cost and Considerations
Attic insulation installation ranges from $1.50 sq/ft. to $2.45 sq/ft. The average cost of attic insulation installation is $1.80 sq/ft.
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.
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.