How Many Inches Of Blown Insulation In Attic – Expert advice from Bob Vila, the most trusted name in home improvement, home remodeling, home repair and DIY. Tried, true, trusted home advice
8 Things to Know About Blown-In Insulation Learn about the materials, methods and costs of this insulation solution so you can make your home more comfortable and your utility bills lower.
How Many Inches Of Blown Insulation In Attic
Today’s building codes require a minimum amount of insulation in walls and attics, but older homes are often under-insulated, so the answer for some homeowners may be blowing out the insulation. Blown-in insulation consists of small pieces of material (think confetti) that are literally blown into walls and attics through a long hose. Keep reading to find out if blown-in insulation is your solution to comfortable conditions and lower energy bills.
Does My Attic Have Enough Insulation?
During new construction, thick strips of batt insulation—spun fiberglass or a paper-based product cut to fit between wall studs and ceiling joists—are laid first to increase wallboard insulation values. Installing batts in most existing homes is rarely feasible because the drywall would have to be torn out, a messy, expensive, time-consuming proposition. Blown insulation can be added to attics and walls without difficulty. What’s more, this type of insulation can seal small gaps and spaces when settled, filling these sneaky spots where cold air can enter. And in addition to creating an insulating envelope, blown-in insulation helps reduce sound transfer between the outdoors and the outdoors. Indoors, so unwanted road noise is also softened.
To install blown-in insulation in existing walls, holes are drilled at the top of each stud space (usually on the outside), and the material is blown in through a long, flexible hose. The hole is then closed with a plug that matches the siding. While the plugs closely match the color of the siding, if the siding is brick or stucco, the plugs are more noticeable.
Another disadvantage of blown-in insulation for walls is that an obstruction in the wall space — such as a drainpipe, outlet box, or any other type of unseen barrier (for example, cross-board stability between studs added by the builder) — can keep the insulation from filling the entire stud space, leaving a void with no insulation.
After a few years, the blown insulation settles down a few inches, which slightly lowers its overall thermal resistance (called the R-value), because it leaves a small portion uninsulated at the top of the stud space. Blowing in extra insulation is an option, but most homeowners skip this step because it’s a small area.
Types Of Attic Insulation: Pros And Cons
Some tasks are better left to the pros. Find a trusted local insulation expert and compare multiple quotes for your project.
Anyway, what is blown-in insulation made of? The three most common types of blown-in insulation are loose-fill fiberglass, cellulose, and rock wool—each with their own pros and cons. Minimum recommended insulation values vary by geographic zone, and you can find the recommended values for your area on this Energy Star map. The higher the R-value of blown insulation, the greater the insulating effect. Not all types of blown-in insulation offer the same thermal value, but in most cases, adding some insulation is better than none at all.
For all of the above types of insulation, hiring a professional installer adds approximately $15 per square foot in labor fees. (See below to learn about taking on this as a DIY project.) Federal tax incentives for home insulation expired in 2011, but some homeowners can still take advantage of state tax credits, which help offset insulation costs. Check the Department of Energy’s DSIRE website to see if you can benefit from tax credits.
Bags of both cellulose and loose-fill fiberglass insulation are readily available at most lumberyards and home improvement stores. However, rock wool insulation may need to be ordered (from the same stores), as it is a more specialized material. Along with insulation, you’ll need a blower if you want to install it yourself. Some stores will give you a blower for free if you buy 10 or more bags of insulation.
The Five Major Factors Influencing The Cost Of Attic Insulation
As with all home projects, the question “Can I do blown insulation myself?” It’s natural to wonder. Blowing insulation to walls is best because it involves drilling into stud spaces that contain electrical wiring and pipes. However, blowing insulation into one
Can be a DIY task. It doesn’t require any special skills but you will need to crouch under low, sloping attic rafters to evenly distribute the insulation. Follow the instructions printed on each bag of insulation and blower, as well as the tips below to help you complete an attic-insulating project safely and successfully.
While this is a long-term solution for most homes, will blown insulation need to be replaced at some point down the road? Broadly speaking, blown insulation can last anywhere from 20 years to the life of a home. Under ideal conditions (eg, professional installation, little or no water damage, minimal settling), this insulation material maintains its high thermal resistance for decades.
Fiberglass insulation typically lasts about 80 to 100 years, but it should be checked for signs of damage about 15 years after installation. Meanwhile, rock wool is particularly moisture-resistant and requires replacement over the lifetime of a home lasting up to 100 years. Although it’s the most environmentally friendly blown-insulation option of the three, cellulose insulation lasts an average of 20 to 30 years due to its recycled makeup and low moisture resistance. As with fiberglass insulation, homeowners should begin testing cellulose insulation in the attic for significant degradation about 15 years after it is installed.
Attic Insulation Damage
Just as DIY blown-in insulation installation is possible, it’s also feasible to remove blown-in insulation from your attic yourself with the right tools and protective equipment. Contractors often use large industrial vacuums to remove blown-in insulation, but it’s possible to vacuum up all the insulation in an attic with a high-capacity wet/dry shop vacuum or HEPA vacuum. You will often need to vacuum bag the contents of the attic trusses until they are clear of insulation. Otherwise, you can rent an industrial vacuum to make the job easier or hire a professional to do the job for you (the latter is necessary when removing blown insulation from walls).
Before you vacuum attic insulation, protect yourself first: wear long sleeves, pants, gloves and a respirator to avoid skin or lung damage, and use a headlamp or work light so you can see what you’re doing. It’s also recommended to work with a partner when you’re installing it, removing blown insulation. After removing all insulation from the attic, contact your local waste management authority for recommendations and instructions on how to properly dispose of your particular type of insulation.
How much does blown-in insulation cost? It depends on how it is installed. Labor is an important factor; Contractors typically charge between $40 and $70 per hour. Labor costs are essentially unavoidable when installing blown-in insulation in walls, but those hourly charges can be ignored by DIYers who insulate their attics. The DIY approach comes with its own costs, however, as blowing machine rentals typically run from $100 to $200 per day.
An important insulation cost to consider is insulation. Including labor, fiberglass is the most affordable of the three options at about $0.50 to $1.10 per square foot, followed by rock wool at $1.40 to $2.10 and cellulose at $2.00 to $2.30. Materials are not the only driver of cost, as the R-values required for insulation by local building codes differ between attics and walls. Attics (R-30 to R-60) generally require higher thermal resistance than walls (R-13 to R-23). Combined with the large surface area of most attics, this makes attic blown insulation more expensive than blown wall insulation. Blown insulation costs $1.00 to $2.80 per square foot, depending on type, location, R-value and base. Be it cellulose, fiberglass or rockwool. Blown-in attic insulation costs an average of $900 to $3,600. Blown-in wall insulation for the exterior walls of a home costs $1,900 to $7,800.
How Much Attic Insulation Should I Have? — Insulusa
Blown-in insulation averages $1.00 to $2.80 per square foot. Prices range from $0.50 to $5.00+ per square foot depending on type, R-value and project location and size.
Blown-in attic insulation ranges from $0.90 to $2.40 per square foot, or an average of $900 to $3,600. Blown-in attic insulation is preferred because it easily fills gaps, joints and hard-to-access areas.
Blown-in wall insulation costs $1.10 to $3.70 per square foot, or $1,900 to $7,800 to insulate all exterior walls. The type of insulation, the number of walls and whether the insulation is installed from the interior or exterior will affect the total cost.
Blown cellulose insulation costs $0.60 to $4.20 per square foot, depending on the type and size of the project. Cellulose’s R-value of 3.1 to 3.8 per inch provides a better thermal barrier than fiberglass. Cellulose is also environmentally friendly as it is primarily made from recycled newspaper.
Reasons To Avoid Diy Blown In Insulation In Attics
Wet cellulose insulation costs $0.60 to $2.00 per square foot installed. Wet-spray or wet-spray insulation is a mixture of loose-fill cellulose, fire retardant, water, and spray adhesive.
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