R50 Insulation Thickness Guide (Table for All Types) - The Tibble (2024)

By: Author Michael Scott

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R50 insulation is not the most commonly used rating for insulation. Even so, with the various options and choices that can be made regarding insulation, knowing about R50 is a helpful piece of knowledge to have.

This article will discuss not only R50 but also R49 and the differences between the two, and why R49 tends to be more common. Most importantly, though, in this article, you will find a straightforward and easy-to-read table for R49 and R50 thicknesses.

R50 Insulation Thickness Guide (Table for All Types) - The Tibble (1)
R49 is more commonly specified. R50 can be used instead, but the greater cost is not necessarily matched with greater insulating power. The thinnest layer achieving R50 is 8.3" with closed cell spray foam. The thickest layer achieving R50 is 20.8" with loose-fill fiberglass.

R49 vs R50

R50 insulation isn’t commonly discussed. R49 is much more common.

This is mostly because the increase from R49 to R50 doesn’t really offer a notable difference as far as improved function of the insulation. It would be like adding more insulation (so more cost) for essentially the same perks as what is offered with slightly less insulation.

It is also easier to find sellers who sell amounts of their insulation that equate to R49. It is more uncommon, on the other hand, to find that type of situation for R50.

Where Is R49/R50 Insulation Required?

Insulation R-values of 49 and 50 are relatively heavy-duty ratings.

Both R49 and R50 stop around 98-99% of the heat that could pass through solid materials.

Having higher insulation ratings, R49 or R50 insulation is most commonly used in attics. This will be discussed further below.

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It is important to note that R49 and R50 insulation isn’t required everywhere in the house, and only in certain climate zones (also to be discussed).

This is to say that it is important for one to check local codes to see what the particular requirements are for your area.

R49/R50 Insulation Is Primarily Used in Attics

R49 and R50 insulation is mostly used in attics and ceilings. This is because a great deal of heat can be lost through these high points, so having a thicker amount of insulation there is more important for keeping heat in.

Attics also tend to hold a lot of heat. So, thick insulation is important in an attic in order to protect the areas of the home that have a regulated temperature.

For example, in a hot summer if you had your air conditioning on and the house was kept at 68 °F, the attic may still be extremely warm. It is not uncommon for attics to reach temperatures of 140 °F!

This heat can affect the temperature of rooms below it, making your HVAC system work harder to maintain the low desired temperature.

R49 or R50 insulation is then very valuable as it prevents the extreme heat in the attic from impacting the areas of the home that are trying to be kept cool.

Only Some Climate Zones Require R49/R50

Only certain climate zones require R49 or R50 insulation. Table N1102.1.3 of the International Residential Code (IRC) explicitly explains these regulations.

R49 is only required in the ceilings of zones 2 and 3 (which are hot climates). R50 is not explicitly required anywhere, but could be used in place of R49.

Some states included in zones 2 and 3 are Florida, Louisiana, and Alabama. These climates need thicker insulation in the ceiling so that the oppressive heat, which is so common there, is not seeping into the house and impacting the temperature within the home.

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Having thicker insulation in the ceilings and attics can also be helpful in reducing the noise of weather. Specifically in zones 2 and 3, rain is extremely common, which could be quite noisy. But having thicker insulation will help reduce weather-related noises.

R49 and R50 Insulation Thickness Guide: Table

Insulation TypeInherent R-value (per inch thickness)Thickness to achieve R49Thickness to achieve R50Best-selling option
Loose-fill fiberglass2.2-2.7± 16.7″± 20.8″Owens corning 19
Loose-fill mineral wool3-3.3± 12.7″± 15.9″R15 comfortbatt
Loose-fill cellulose3.2-3.8± 11.4″± 14.3″Borate only cellulose
Fiberglass batt (amazon link)3.1-3.4± 12.5″± 15.6″Knauf insulation EcoBatt
Mineral wool batt3-3.3± 12.7″± 15.9″Havelock Wool
Plastic fiber batt3.8-4.3± 10″± 12.5″JM Comfort Therm Fiberglass
Natural fiber batt3.4± 11.8″± 14.7″ Owens Corning
Open cell polyurethane spray foam3.5± 11.4″± 14.3″Loctite tite Foam
Closed cell polyurethane spray foam (amazon link)5-7± 6.7″± 8.3″ Tiger foam
Foam boards3.6-8± 6.9″± 8.6″SilveRboard
R50 Insulation Thickness Guide (Table for All Types) - The Tibble (4)
R50 Insulation Thickness Guide (Table for All Types) - The Tibble (5)





R50 Insulation Thickness Guide (Table for All Types) - The Tibble (2024)


How thick is r50 insulation? ›

You see, cellulose insulation has a higher R value per inch than loose fill fiberglass insulation. We are a cellulose installer. To achieve R-40, we install 12” of cellulose insulation. To achieve R-50, we install 15” of cellulose insulation.

What is the recommended thickness of insulation? ›

For insulation rolls and batts, the recommended thickness level is 270mm. This is what you will have to insulate to in a new property, and what you should be aiming to insulate to in an older one. If starting from nothing, you will probably have to buy and install two rolls or batts.

What does R60 insulation mean? ›

R49 or R60 insulation is necessary for extreme climates, but they can be an unnecessary expense if you live in a more temperate area. Typical R-values range from R13 to R60, although some products may offer higher or lower values. The higher the R-value, the better the insulating power of that material.

What is R50 insulation? ›

A higher R-value indicates a higher resistance—for example, an R50 product provides significantly higher heat resistance than an R30 product. Why does this matter? The more resistance your insulation product provides, the more control you have over the heat transfer in your home.

What is R50 insulation used for? ›

Zone 7A/7B
Ceiling Below AtticsR-50 Batt or Blown Insulation
Cathedral Ceilings & Flat RoofsR-31 Batt Insulation
Floors Over Unheated SpacesR-28 Batt Insulation
Walls Above GradeR-19 Batt Insulation
1 more row

How thick is R49 blown in insulation? ›

6 more rows

What is the difference between R38 and R49? ›

R-38 is Fall & Spring protection. > R-49 gives you Winter & Summer protection. During Atlanta's hot sunny days, you might squeak by with R-38 if you have plenty of mid-day and afternoon shade and a lighter colored roof.

Is R49 worth it? ›

R49 insulation is a wise choice for your attic, providing year-round comfort and substantial energy savings. It's a valuable investment in your home's efficiency and your family's comfort. For flawless attic insulation installation, it's essential to consult a professional insulation contractor like Green Attic.

Can insulation be too thick? ›

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.

What is the thinnest insulation with the highest R-value? ›

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).

How do I know what size insulation to use? ›

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 many inches thick is R60? ›

R 60: Thickness that oscillates between 19 and 22 inches. R 70: Thickness that oscillates between 22 and 25 inches. R 80: Thickness that oscillates between 25 and 28 inches.

Can you over insulate a house? ›

The short answer is, yes, you can over-insulate your home. While your home should be well-insulated against the cold and keep you cool during hot summer months, that doesn't mean you should cram the walls full.

How thick is R60 blown? ›

Technical Information
Blown Inches4.521.5
Coverage/bag (ft2)162.030.5

How many inches thick is r60 insulation? ›

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How thick is R30 insulation? ›

9.5 in - R30 - Fiberglass Insulation - Insulation - The Home Depot.

How thick is R 40 insulation? ›

R40 is 11-inch thick, it is difficult to install it from the inside of the house.

How many inches of insulation is r60? ›

Cellulose rated at R-60 is about 16 or 17 inches deep. Cellulose rated at R-100 is about 27 or 28 inches deep.


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