Option: When installing multiple layers of insulation for optimal thermal performance, install the first layer (bottom layer) parallel to attic framing members and flush with both bottom and top. Install the second layer (top layer) perpendicular to attic framing members.
Roof insulation batts can be added in more than one layer. Adding a double layer of roof insulation negates the effects of thermal bridging and seals any gaps that may be present in the first layer.
As a general guideline, it's advisable to install double layers of thermal insulation throughout your house.
In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.
Yes you can do this. I've seen blown insulation on top of batts. Batt insulation on top of blown insulation. Both on top of insulation board. In every case, the overall r-value was improved.
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.
It is important to leave a small air gap between boards and the mineral wool in order to stop damp forming. Remember that insulating between the joists will create a cold roof space as the heat is kept underneath the insulation like a blanket.
You will be able to add new ceiling insulation batts on top to reach the ideal R-Value in your roof. To learn more about assessing your existing ceiling insulation for its condition and thermal R-Value check out our blog: WHAT R-VALUE INSULATION IS IN MY ROOF AND CEILING.
ABOUT INSULATION
The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half.
Place an insulation hose into the hole, and blow the insulation product until the space is full. Remove the hose, and cut 3” x 8” strips of plywood. Insert a plywood strip into each hole, securing it with screws above and below the hole. Replace the hole cutout, and attach it to the plywood using a drywall screw.
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.
Insulation Batts
Batt insulation is a type of insulation blanket. These are pre-cut sections of insulation that are usually fiberglass, although cellulose, mineral wool, natural fibers and plastic versions are also available. This type of insulation is the best insulation for unfinished walls, floors and ceilings.
The recommended thickness for attics is typically 12-16 inches. Spray foam insulation: As discussed earlier, the recommended spray foam insulation thickness can vary depending on factors like climate and location. For attics, a thickness of 2-4 inches is usually sufficient.
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.
When it comes to insulation, it's generally recommended to leave a gap between the insulation material and any other surfaces, such as walls, ceilings, or roofs. This gap provides ventilation and prevents moisture buildup, which can lead to mould and other problems.
Installing more insulation in your home increases the R-value and the resistance to heat flow. In general, increased insulation thickness will proportionally increase the R-value.
Our two-layer solution includes a dense first layer, ensuring the expected thermal performance is still delivered when compressed. Learn more below. We are seeing greater use of a two-layer system, often with traditional R3.
Double or reinforced insulation is another method of protection against electric shock, consisting of an extra layer of supplementary insulation over the basic insulation, or a single layer of special reinforced insulation directly over the live parts.
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.
For 2×6 walls, you need an R-value of 19, and the recommended wall insulation R-value for all zones falls between 19 to 21. If you decide to insulate the ceilings, they should have a minimum ceiling insulation R-value of 30.
Exposed insulation is at risk of catching fire if not covered properly because it is extremely flammable. Installing a fire retardant plastic sheeting over insulation slows the fire damage rate in the case of an adverse event.
In many cases you can install new insulation over old. Your old insulation may not be very effective on its own any more, but it probably has some insulating power. And every bit counts!
Should you leave a gap between the insulation and the roof? Yes, you should leave an air gap between the insulation and the roof to allow proper ventilation and prevent moisture buildup.
In climates that are hot and humid, a vapor barrier should be installed on the warm side (for walls, this would be just beneath the exterior cladding, over the insulation). For very cold climates, the warm side is the interior, so the insulation should have a vapor barrier separating it from the interior wall.
Therefore, when installing foil faced insulation always fit the foil side where the temperature difference is greatest. So, any time you use a single side foil insulation, the foil needs to be facing toward the living space.