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. Now R-Value ranges widely across products and home applications. Indeed you will see R60 in some places and R13 in others.
R13 insulation is generally more affordable, which makes it an attractive option for budget-conscious projects. However, R19 insulation offers better long-term advantages because of its higher R-value. Why? Because the R-Value translates to a greater energy savings over time.
r19 just means its thicker insulation, made to fit into a 2x6 frame where the r13 is meant to fit in a 2x4 frame. the insulation is soft and will press in fine and won't offer as much of an air buffer in the insulation but will still accomplish the job just fine especially for a garage situation.
R13 is about 92% reduction in heat transfer. R19 is about 2-3% better than R13. It's an exponential decay in heat transfer, so you'll be fine with it for a garage. Use the thicker stuff for the attic to reduce transfer from the attic to the garage.
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.
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.
Fiberglass insulation is the most common type of insulation used for garages. Fiberglass insulation is likely the material you picture when you think insulation — that's right, the fluffy pink stuff. This is because fiberglass is the most commonly used insulation for homes, garages and most other types of buildings.
The cost to insulate a 24' x 24' garage is $3,000 - $8,000. Garage size influences the cost of insulation. The 24'x24' garage will house 2 cars and some extra space for other purposes. The average cost to insulate a 24x24' garage with spray foam is $6,000.
Insulating an unheated garage alone may not necessarily cause mildew, but the risk of mildew increases if there isn't proper ventilation. Insulation can trap moisture in the garage, especially in humid climates, creating a perfect environment for mildew growth.
To achieve optimal U-value, garage wall insulation is generally recommended to be 50mm to 100mm thick.
For a detached, uninsulated garage – in this case, an uninsulated door or an R‑6 rating should work. 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.
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.
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.
R-13 insulation offers a balanced blend of cost-effectiveness and thermal resistance, making it ideal for standard 2x4 wall cavities, floors over unheated spaces, and crawl spaces.
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.
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!
The majority seem to agree that insulated, unheated garages, should be allowed to breathe. If the garage is heated, you will need a vapor barrier, otherwise you will get frost and mold.
Should I Put Vapor Barrier Plastic Over Insulation Before Drywall? Yes, covering your insulation with a vapor barrier plastic before installing drywall is crucial. It prevents moisture buildup that can lead to mold, rot, and even structural damage.
Final Cost of Insulating a 40'x60' Steel Building
After you factor in the costs of materials and the costs of construction, you'll find that it will run you between about $2,400 and $6,600 to insulate your 40'x60' metal building.
Fiberglass is the most popular insulation solution for metal building systems because it provides the lowest installed cost per R-value. With various facing solutions, the fiberglass insulation will result in a durable and attractive finish whilst giving speedy construction times.
The average cost to drywall a garage is $800 to $5,000, depending on the size and the finish level. Garage drywall installation costs $1.50 to $3.50 per square foot of wall or ceiling surface.
What R-value insulation should I use in my garage? Generally, insulation with an R-value between R-13 and R-21 is recommended. Adding insulation to exterior walls (including garage walls attached to living spaces) can help increase R-value and create a more powerful thermal boundary for your home.
Some garages have traditional ceilings that run perpendicular to the floor and have a crawl space above them. To make things easier, you'll need to install drywall before adding insulation.