You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.
Provided the existing rolls are in good shape, you can absolutely retrofit batt insulation with blown-in insulation! Materials can even be mixed, such as blowing in cellulose insulation on top of fiberglass batts (or vice-versa).
CAN YOU LAY INSULATION OVER INSULATION? STACKING INSULATION ON TOP OF INSULATION. Adding a new layer of insulation over older insulation can be a good idea if the old insulation is dry and in good condition. However, there are circumstances where you should avoid installing new insulation over the existing layer.
Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half. Each time the insulation layer is doubled in thickness, this rule applies.
It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers.
Also, when laying down additional insulation, work from the perimeter toward the attic opening. Never lay insulation over recessed light fixtures or soffit vents. Keep all insulation at least 3 inches away from recessed "can" lights, unless they are rated IC (Insulated Ceiling).
A well-sealed and insulated attic can make a real difference in your energy bills and how comfortable your home is. Considering how high energy bills are these days, now is a great time to improve your home with a cost-effective project like sealing and insulating your attic.
Because its structure is more complex than single-layer insulation, the cost is relatively high. Additionally, in some cases, double-insulated cables may fail due to spalling between the inner and outer insulation layers.
R19 Insulation offers superior thermal insulation compared to R13. With a typical thickness of 6.25 inches, R19 fiberglass is designed for use in 2x6 wall cavities, making them suitable for colder climates where higher thermal resistance is necessary.
Adding two R-13, 3.5” batts to a 2”x6” (5.5”) wood stud cavity will not provide an R-26. The total of 7” of insulation is reduced in thickness to 5.5” thereby losing the R-value associated with its full thickness.
In general, either batt or rolled insulation or blown loose-fill insulation (fiberglass or cellulose) can be installed on top of old insulation. If you need to add new insulation on top of old insulation please note the following: Draftproofing should be completed prior to the addition of more insulation.
You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.
Removing old insulation is generally recommended if it's damaged, contaminated with mold, or infested with pests. However, if the insulation is in decent shape and just needs a boost, adding a new layer on top can be a cost-effective option.
This is because the second layer of insulation prevents any possible contact between the live parts and the casing. Therefore, even if the appliance is handled or touched when a fault has occurred, the user is still protected from electric shock.
If you're adding more insulation to an attic that already has insulation, use unfaced insulation. However, if there is already faced insulation with the paper facing the inside of your home, you cannot stack unfaced insulation over it.
If you double the thickness of your insulation, you're essentially giving its R-value a twin sibling. Double trouble, double warmth!
You will want to bring up your attic up to R-38:
If your attic has 5-6″ of existing insulation, you'll want to install an R-19 to achieve a total of R-38.
R15 insulation offers slightly better thermal insulative properties than R13. Some of its formats are a fraction of an inch thicker than R13, making it more effective at helping with energy efficiency. However, the difference is minimal. R15 is slightly thicker than R13 for spray foam and blown-in cellulose.
If your insulation is just level with or below your floor joists (i.e., you can easily see your joists), you should add more. If you cannot see any of the floor joists because the insulation is well above them, you probably have enough and adding more may not be cost-effective.
For most long-term applications, double bubble foil insulation is going to be the better option to use. Because of the double layer of polyethylene bubbles, double bubble insulation provides the most effective thermal break, making it harder for radiant heat to transfer through than with single bubble insulation.
Double insulation might be required in several situations such as in areas with extreme weather conditions, in businesses that require noise reduction, when aiming for maximum energy efficiency, and in order to comply with certain building regulations.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
Insulating your attic floor can create a vented attic, which is ideal for storage and not needing temperature control upstairs. Insulating the ceiling will make an unvented attic, which allows you to control the temperature for temperamental storage items, living space, and HVAC ductwork.
While loft insulation is an effective way to improve energy efficiency and reduce heating costs, over-insulating can lead to several potential issues. Firstly, over-insulation can lead to poor ventilation in the attic, which can cause moisture buildup and increase the risk of mould growth.