What insulation do you use for 2×8 walls?

What insulation do you use for 2×8 walls?

Two-by-Eight Floor Joists 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.

How do you insulate a 2×8?

Insulating 2×8 Cathedral Ceiling

  1. Use R19 per the building department.
  2. Compress R30 batts (9 ½) and get approximately R25 (per Owens Corning).
  3. Use Un-faced R13 Batts (3 ½ inch) and then cover these batts with Faced R15 (3 ½ Inch).

What insulation has the highest R-value per inch?

Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.

What is high density insulation?

“High density” means more fibers per square inch than standard insulation products. That means you get a higher R−value per inch. As with all PINK fiber glass insulation, high density insulation products will not hold water, thereby resisting any permanent loss of R−value.

What is the best R rating for insulation?

Depending on where you live and the part of your home you’re insulating (walls, crawlspace, attic, etc.), you’ll need a different R-Value. 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.

How thick is r21 batt insulation?

5½ ”
5½ ” thick R-21 EcoTouch® insulation delivers 19% more R-value than compressed 6¼ ” R-19 Fiberglas™ insulation. The kraft facing on this insulation will burn and must not be left exposed.

How much R-value do you lose when compressing insulation?

However, when you compress a batt of a particular thickness, the total R-value does decrease. For example, standard low-density batts, at their nominal rated thickness — R-11 at 3 1/2 inches, or R-19 at 6 inches — have an R-value of about 3.1 per inch.

What is the thinnest insulation with the highest R-Value?

Thermablok® Aerogel
Thermablok® Aerogel is a revolutionary advancement in thermal technology offering the thinnest insulation available to prevent thermal and cold bridging. Classed as a Super Insulation, Aerogel has the highest insulation value of any known material with the lowest thermal conductivity value of any solid (0.015W/mK).

What is the best R rating for ceiling insulation?

Select the right R value For the Victorian climate the recommended minimum R value for bulk ceiling insulation is R3. 5. In Victoria’s alpine climates higher levels of insulation are required – aim for R5. 0 to achieve greater comfort and energy savings in your renovated home.

How thick is R38 high density insulation?

10¼ ”
10¼ ” thick, R-38C EcoTouch® Thermal Batt insulation prevents moisture damage and help assure long roof life by providing 1″ of ventilation air space between the insulation and roof deck.

How thick should insulation be?

In the attic: A good rule of thumb for insulating your attic is to make sure it is at least as tall as your ceiling joists. If you only have a few inches of insulation in your attic, you are likely wasting money on your energy bills. Build it up to at least 12 inches for optimum insulating power.