Compressing insulation designed for 2×8 into a 2×6 cavity will yield a negligible R-value difference. You can buy R-21 insulation for 2×6 cavities but if you buy R-30C then it will only be worth R-22 once compressed. Insulation is a delicate balance of air space and fiberglass.
What insulation do I use for 2×8 ceiling?
Two-by-Eight Floor Joists
This leaves a 15-inch cavity between joists. According to Peter Ainsworth, fiberglass R-19 batt insulation is about 6 inches thick and is available in 15-inch widths, making it the correct size for insulating a two-by-eight floor joist system.
What is the best thickness for ceiling insulation?
Recommended Ceiling Insulation Thickness
- 8 to 10 Inches. When insulating ceilings in warmer climates, or when using higher density materials, as little as 8 inches of thickness may suffice. …
- 10 to 12 Inches. …
- More Than 12 Inches.
What insulation should be used in ceiling?
Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces. See the Department of Energy’s (DOE) ranges for recommended levels of insulation below.
Do you put insulation in the ceiling?
In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, cathedral ceilings, floors over unheated garages or porches, knee walls, and in between interior walls—especially bathrooms—as well as ceilings and floors.
How do you insulate a 2×6 ceiling?
Quote from the video:
Quote from Youtube video: 2 inches thick is roughly our 11.4 I think yes 1 inch is 5.7. So 2 inches is 11.4. So to get our. 30 you have to have at least three layers of this stuff. So three layers will be six inches deep.
Can I use R30 in ceiling?
R-30 insulation provides the minimum level of heat-transfer loss to your home. You can keep your energy bill lower with R-30 insulation on your ceilings.
Do you need an air gap for insulation?
Insulation is technically a solid with a lot of air in it therefore, it is NOT an air gap. You literally must have a VOID, nothing in the air gap except air itself. So if you are installing under a roof or in a wall, you must create an air gap.
Can insulation be thicker than joists?
For the most effective results, insulation that is thicker than the depth of the ceiling joists should consist of two or more layers. The thickness of strips making up the first layer should equal or exceed the width of the ceiling joists.
What thickness of insulation do I need?
What Insulation Thickness Do I Need for Flat Roofs? An uninsulated flat roof has a U-Value of around 1.5 W/m2K. When insulating one, you’re aiming for a value of 0.25 W/m2K or less. To achieve this, you should insulate your flat roof with insulation boards totalling around 150mm thickness.
Should I put plastic over insulation before drywall?
Without poly beneath the drywall, water vapor hits the drywall and diffuses through to the drier (in summer) indoor air. By installing a sheet of poly there, you cut off that drying mechanism and water that finds its way into walls can stay there longer and do more damage.
How do I install r30 insulation in my ceiling?
Quote from the video:
Quote from Youtube video: Once the rafter mates are in place you can begin installing insulation simply push the bat straight up through the ceiling joists. Then pull it back down. So the bat fits evenly in the space.
Is it better to insulate ceiling or roof?
If you are deciding between insulating the roof deck or the ceiling, Insulating your ceiling should be the priority. Not only is it easier but ceiling insulation is beneficial in a number of ways: Keeps the temperature in the building regulated. Saves on energy costs.
Can I insulate the underside of my roof?
Open-cell spray polyurethane foam or closed-cell spray polyurethane foam (ccSPF) insulation can be sprayed along the underside of the roof sheathing to provide a conditioned and insulated attic space that can be durable and efficient in all climate zones (see Figure 1).
Should I insulate the joists and rafters?
Insulating between the joists of your loft will keep your house warmer, but make the roof space above colder. This means pipes and water tanks in the loft space could be more likely to freeze, so you will need to insulate them.
Should I insulate ceiling between floors?
In unfinished attic spaces, insulate between and over the floor joists to seal off living spaces below. If the air distribution is in the attic space, then consider insulating the rafters to move the distribution into the conditioned space.
Can you over insulate a house?
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. That’s when mold starts to grow.
How do you insulate a ceiling between floors?
Quote from the video:
Quote from Youtube video: But that's an easy simple fix all you do is you take an acoustic ceiling like. This. You fill in the hole like that.
