This insulation type is commonly used in exterior walls, attics, and areas where additional insulation is required to maintain comfortable indoor temperatures. R19 insulation also provides better moisture control, thus reducing the risk of mold and mildew growth.
R19 insulation is a thicker, more robust option—offering higher thermal resistance. Commonly used in colder climates, R19 is well-suited for 2x6 wall assemblies, floors, ceilings, and attics.
R19 Insulation is any type of insulation that achieves that specific R-Value measurement of R19. R-value is used to judge thermal insulation performance and the higher the number, the better the product's insulating ability. So R19 has better insulating ability than R13.
R-19 in a 2x4 stud cavity is a bad idea for two reasons. 1 - compressing fiberglass batt insulation reduces the effective R-value. 2 - the insulation pressing on the back of the sheet rock will cause bulges in it and make the board hard to attach to the framing.
If your attic has little or no existing insulation, you'll want to install an R-38 rated material. If your attic has 2-3″ of existing insulation, you'll want to install an R-30 to achieve a total of 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.
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).
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.
Aerogel insulation offers the highest R-value of any insulating material at less weight and thickness—ideal for construction, refineries, pipelines, and thin-gap thermal barriers.
If the existing attic insulation is an R-19, you may choose to add another layer of R-19. Two layers of R-19 at 6¼ ” thick will achieve a total R-value of 38. So adding an R-19 batt to an existing R-19 batt will give you a total insulation value of R-38.
Insulation For 2x4 Walls
Use R-13 or R-15 kraft-faced fiberglass or mineral wool insulation rolls for 2x4 stud walls. Wall assemblies, especially those in older homes, are built with two-by-four (2x4) studs. The wall thickness will be 3-1/2 inches, not 4 inches. The width of modern 2x4s is 3-1/2 inches.
By our rough estimate, for a garage heated consistently throughout the winter, insulating four walls, garage doors, floor, and ceiling to R-19 would result in about $1050/year in energy savings!
While both types provide insulation, R30 is the better option for maximizing energy savings in areas where heat loss or gain is a major concern. For example, R19 may suffice for interior walls, but R30 is more appropriate for exterior-facing attics or floors.
Many factors contribute to the high cost of insulating a new construction home. Between the quality of materials, labor costs, and regulatory compliance, insulation costs can add up quickly. Investing in premium insulation like spray foam is an expensive choice.
What R-value insulation should I use in my garage? Generally, insulation with an R-value between R-13 and R-21 is recommended.
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.
Applications: R-19 polyiso insulation is well-suited for milder climates and it provides a cost-effective solution for walls, roofs, and cavities. In colder climates, R-21 polyiso provides enhanced performance by reducing heating and cooling costs over time.
In fact, adding too much insulation to your walls can lead to problems such as poor ventilation, mould growth, and condensation. This is because thicker insulation can block airflow and trap moisture, leading to indoor air quality issues and even structural damage.
For example, homeowners in the southern United States can begin insulating their attic using materials that have R-values in the R30 to R60 range and R13 to R19 insulation ratings for the floors. Attic insulation should be R49-R60, while floor insulation should be R25-R30 for those in the north of the United States.
The material should be faced if you install batting between your attic floor joists. Since the attic floor is the ceiling of the living space below, the facing is installed against the top of the ceiling drywall or plaster.
Spray Foam Insulation
Spray foam also offers a high R-value per inch, but while spray foam insulation has a lot of benefits, it is also one of the most expensive types of insulation. Professional installation is recommended to ensure that the foam is applied evenly, effectively, and safely.
The optimal R-value for most homes is 30, but you can go as high as 38 if you live in a tropical climate. Anything higher than 38 indicates an over-insulated space. While you might think that too much insulation can't be bad, there are some significant consequences to consider.
For an attached garage – since these spaces are typically well insulated you'll want to make sure you've got at least an R‑value of R‑12, as well as ensure that the door itself has good resistance to cold temperatures.
The Benefits of Unfaced R19 Insulation
You can use it in many parts of your home, including attics, crawl spaces, and between studs in walls.
The DOE Insulation Fact Sheet (DOE/CE-0180) can be ordered from the Energy Efficiency and Renewable Energy Clearinghouse or accessed from the Internet at www.ornl.gov/ roofs+walls. Fiberglass and rock wool batts—2x4 walls can hold R-13 or R-15 batts; 2x6 walls can have R-19 or R-21 products.
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.