Insulation R values of various materials:

Here we provide extensive Tables of Insulation Values and Properties for Various Insulation & Building Materials or other substances useful in procedures to measure or calculate heat loss in a building.

Page top photo by the author, the Formula-R and Owens Corning markings, which may be visible in this photograph of pink Styrofoam insulation boards, are registered trademarks of Owens Corning and were photographed at a Home Depot® building supply center.

Insulating Characteristics of Various Materials

These tables give R-values of all sorts of materials, in alphabetical order with direct links to some popular insulating materials.

They also give the insulating value of any material of interest in construction, for example: air, fiberglass, masonry mateirals, mineral wool, cellulose, foam insulating board, UFFI, soil or dirt, vermiculite, wood, & most other building materials.

Here we provide first an alphabetic index to the insulating or R-values of all sorts of building materials, even substances like air and dirt.

Photo: yellow fiberglass insulating batts in a sloppy insulation installation job.

Alphabetic Index to Insulating or R-Values of Materials

A  -  B  -  C  -  D  -  E  -  F  -  G  -  H  -  I  -  J  -  K  -  L  -  M  -  N  -  O  -  P  -  Q  -  R  -  S  -  T  -  U  -  V  -  W  -  X  -  Y  -  Z

Below we also give links to skip directly to popular insulation materials or just skip directly to the start of the COMPLETE INSULATION DATA TABLE where you will find that we list all building materials and insulating materials in alphabetic order.

Nearly all building materials are found there as well as the insulating properties of other materials of interest.

Tip: Also use the page top Search box to look for our articles about specific insulating materials and their properties.

We also provide conversion values & formulas to convert between U.S., Metric, & Imperial system measures of insulating value or heat loss value.

Conversion Among US, Metric & Imperial R-Value and other Insulating or Rate of Heat Loss/Gain Value Metrics

In general all of the measures of heat-loss or heat-gain insulating properties of materials are measuring the rate at which heat flows through a material.

The "R" value of a material is the material's resistance to heat flow through the material, but different countries or areas of the world use and compute these values differently.

Generally there are three different R-Values:

1. U.S. R-value - written here as R-value _USA
2. Imperial R-Value - written here as R-value _Imperial
3. RSI or metric system or European R-Value - written here as RSI or as R-value _Metric

To convert among R and U values in these different systems:

• U.S. R-Value = Imperial R-Value = R = (Heat Resistance x Degrees F x square feet) / BTUs
• RSI = Metric / European R-Value (m² · K/W)
  
  RSI = 1/U _Europe
• RSI-Values: convert U.S. R-values to SI units or RSI as follows: 
  
  R-Value _USA / 5.685 = RSI-Value _Europe or "metric" or "SI" units
  
  R-1 = 5.678263337 RSI
  or
  
  RSI-1 = 0.1761101838 R
  
  
• Metric R-Value = 0.1761 x Imperial Inch-Pound R-Value
• U-Value = 1 / R-Value for all of theses systems.
• Metric / European U-Value = U _Europe = 1/R-Value _Europe
  
  Also: U _Europe = [watts / kelvin x meters²]
  
  The SI (System International) R-value is defined as units of Kelvin meters (Km) squared per Watt - KM²/W

Also

• US R-Value or Imperial Inch-Pound R-Value = Metric R-Value / 0.1761
  
  R-Value _Imperial measures (ft²·°F·h / BTU)
  
  Imperial (UK or British) units, are expressed as well as square-foot degrees Farenheit (F) per British Thermal Unit (BTU).

See details at HEAT LOSS R U & K VALUE CALCULATION where we explain how to calculate or convert between R-value, U-value, and K-value of materials.

A

Notes on the R-value & K-values of different forms of asbestos:

• Rosato (ASBESTOS INSULATION) is the most authoritative source on asbestos properties and gives data for the thermal conductivity of asbestos in different forms and with varying temperatures. For magnesia-asbestos insulation at mean temperatures ranging from 100°F to 400°F the K-value (thermal conductivity, BTU in. per hr per sq.ft. per °F) ranged from 0.35 to 0.46.
• Details about the insulating, heat, and other properties of asbestos are at ASBESTOS PROPERTIES
• Current sources of asbestos R-values such as engineeringtoolbox provide very inconsistent data: Thermal conductivity k = 0.744 for "cement board", k=0.14 for asbestos millboard, and k= 1.66 for asbestos cement sheets; but the same source puts asbestos cement k = 2.07 and for loosely-packed asbestos k=0.15 - this is very inconsistent data - source: engineeringtoolbox.com retrieved 3/23/2014.
• Calculations converting US R-Values to RSI used the online calculator provided by the Efficiency Matrix website, an Australian company selling products used in building energy efficiency improvement. Tel: 1300 027 874, Email for our Products: sales@efficiencymatrix.com Web: https://efficiencymatrix.com/
  calculator at https://efficiencymatrix.com/r-value-wind-air-flow-imperial-metric-converter/

B

C

...

Notes to the table above

• A: Grouting hollow core concrete block can raise its R-value depending on the grout or fill material but keep in mind that the solid block webs surrounding the holes in hollow core block will continue to conduct heat unimpeded by the filled core.|
  
  In essence if you raise the R-value of the hollow block core area from 1 (the R-value for air) then you raise the R-value for the percentage of the block's thickness comprised by the grouted volume.
• ACI, Guide to Thermal Properties of Concrete and Masonry Systems. ACI 122R-02. American Concrete Institute, 2002.
• NCMA, R-VALUES AND U-FACTORS OF SINGLE WYTHE CONCRETE MASONRY WALLS [PDF] (2013) TEK 06-02C, NCMA, National Concrete Masonry Association, 13750 Sunrise Valley Drive Herndon, VA 20171 USA 703.713.1900 info@ncma.org - retrieved 2023/09/08, original source: ncma.org/resource/rvalues-ufactors-of-single-wythe-concrete-masonry-walls
• NCMA, R-Values of Multi-Wythe Concrete Masonry Walls, TEK 6-1C. National Concrete Masonry Association, 2013.
• NCMA THERMAL CATALOG of CONCRETE MASONRY ASSEMBLIES [PDF] (2012) 2nd Ed. NCMA
  Excerpt:
  The material presented does not cover all possible situations, but is intended to represent some of the more widely used concrete masonry constructions. The R-values provided are steady-state only; and do not take into account concrete masonry’s thermal mass contributions that often offer additional efficiencies for specific projects and climate zones.

...

D

...

...

E

F

...

...

G

H

R-Values of Hardboard & Insulating Boards

I

Notes to the table above:

1. LTTR = Long Term thermal resistance, for panels ranging from 1.5" (LTTR 6.3) to 4.5" (LTTR 24.2) in thickness, OSB laminated to closed-cell polyisocyanurate foam board insulation, OSB on one side, used as roofing nail base, Source: Atlas Roof Wall Insulation, 2000 RiverEdge Parkway, Suite 800 Atlanta, GA 30328 USA Website: https://roof.atlasrwi.com 2020/11/08

Definition: LTTR provides an R-value based on a fifteen-year weighted average thermal resistance, in order to take into account the observation that for some foam insulating materials the R-value diminishes over time, or by some calculations, an eight-year average R-value.

Other versions of nail base include panels with plywood or OSB on both sides, nail base panels incorporating a reflecting surface, and vented insulation panels. Patent examples:

• Roe, Richard, and Robert Blanpied. "Vented insulation panel with reflecting surface." U.S. Patent Application 11/317,245, filed October 19, 2006.
• Schmidt, Kenneth. "Vented insulation for nail based applications." U.S. Patent Application 11/353,735, filed August 17, 2006.

...

J

K

L

M

Masonry Materials R-Values: concrete block, "cinder block", brick, concrete masonry units, perlite filled concrete block

Notes to the table above

Masonry R-values Source: adapted from "Sample R-Value Calculations" found at www.maconline.org

Notes:

1. Effects of water intrusion on insulating value and R-values are not included in the above nor was there discussion of variation in thermal conductivity at block segments that are solid rather than perlite filled.

2. Additional R-value for a masonry wall constructed using these materials needs to add the insulating value of additional wall components typically included, such as 1" solid foam (polyisocyanurate R 8, extruded polystyrene R 5, expanded polystyrene R 4, or 1" of perlite R 2.7) and

for an exterior air film (winter, no wind, R 0.17), an interior air film (again no air movement, R 0.68), 3/4" of reflective air space (no convective air movement, R 2.89), 1/2" drywall (R 0.45), interior wall cavity insulation (see various fiberglass or other insulating values in this table), to achieve a greater overall R-value than that afforded by the masonry block or brick wall alone.

3. Presumably the R-values given are then calcuated for the overall wall structure, averaging the effects of thermal breaks etc. - Ed.

4. Hempcrete R-Values: NADC, Dion, HEMPCRETE A Simple Solution to Housing Problems [PDF] Northern Alberta Development Council Bag 900-14 2nd fl Provincial Building 9621 - 96 Avenue Peace River, AB T8S 1T4 Main: 780.624.6274 Council Email: nadc.council@gov.ab.ca Dion Tel: 780 283 2837 dion@8thfireinnovations.com - retrieved 2022/03/12 original source: https://nadc.ca/media/1343/hempcrete-dion-lefebvre.pdf

N

O

P

...

...

...

... TEST ...

Q

R

Insulating Values of Roofing Materials

...

S

...

Insulating Values of Building Siding Materials

...

T

U

Urea Formaldehyde UFFI Foam Insulation R-Values & Properties

V

...

W

Notes on the R-value of water

• Water has a specific heat capacity or J/ kg °K of 4200.
• For the density of water we quoted Water Density at the USGS Water Science School (2018) - retrieved 2024/02/17, original source: https://www.usgs.gov/special-topics/water-science-school/science/water-density
• Choudhary, M. K., K. C. Karki, and S. V. Patankar. "Mathematical modeling of heat transfer, condensation, and capillary flow in porous insulation on a cold pipe." International Journal of Heat and Mass Transfer 47, no. 26 (2004): 5629-5638.
  Abstract:
  Porous insulation used on pipes carrying cold fluids suffers thermal degradation due to condensation of water vapor and the build up of water in the insulation. ... The presence of the wick is shown to significantly reduce the amount of liquid water in the insulation.
• Endrusick, Thomas L. "Effects of prolonged water contact on the thermal insulation of cold weather footwear." In Proceedings of the Fifth International Conference on Environmental Ergonomics, Lotens WA and Havenith G (Eds.), pp. 188-9. 1992.
• Hall JR, John F., and Johannes W. Polte. EFFECTS OF PROLONGED WATER CONTACT ON THE THERMAL INSULATION OF COLD WEATHER FOOTWEAR [PDF] Journal of applied physiology 8, no. 5 (1956): 539-545.
• Hallett, Paul D., Th Baumgartl, and Iain M. Young. "Subcritical water repellency of aggregates from a range of soil management practices." Soil Science Society of America Journal 65, no. 1 (2001): 184-190.
  Excerpt: An R value of 10, for instance, would indicate that water repellency accounts for a tenfold decrease in sorptivity (ie, the initial wetting rate)
• Kim, Hyunglok, Michael H. Cosh, Rajat Bindlish, and Venkataraman Lakshmi. "Field evaluation of portable soil water content sensors in a sandy loam." Vadose Zone Journal 19, no. 1 (2020): e20033.

...

R-Values of Windows

a. R- Value of Double Celled Window Blinds with Side Rails:

Thanks to Ted Chaban for this note, 2024/04/04, possible references include:

Cellular Window Shades (a vendor of this product) gives R-values for cellular type window blinds ranging from R 1.6 for single-celled light filtering, up to R 4.7 for double celled black-out type window shades with side tracks. - 2024/04/04 original source: https://cellularwindowshades.com/content/33-rvalue-and-insulating-cellular-window-treatments

The actual R-value provided by single or double-celled window blinds will vary by product and product features and also on the percentage of time and time of day during which such shades or blinds are left partly open.

Cameron Bonnell, Louisa Bachman, Caitlin Bugash, Josiane Rosario, Lucas Ghilardi, "A Plan of Action to Green Buildings on Campus Recommendation to the University of Massachusetts Amherst" [PDF] - retrieved 2024/04/04 original source: https://icons.cns.umass.edu/sites/default/files/student-work/2020-06/greenbuildingsustainablebuildingsrecommendationfinaldraft.pdf

Coffin, Donna. (2012). Bulletin #7214, Maine Home Energy: Insulated Interior Window Treatments and Coverings - Cooperative Extension Publications - University of Maine Cooperative Extension. Retrieved May 3, 2020, from https://extension.umaine.edu/publications/7214e/

Kirimtat, Ayca, Basak Kundakci Koyunbaba, Ioannis Chatzikonstantinou, and Sevil Sariyildiz. "Review of simulation modeling for shading devices in buildings." Renewable and Sustainable Energy Reviews 53 (2016): 23-49.

...

R-Values of Wood Building Materials

Notes to the Table of Building Insulation Properties

Because no amount of insulation can keep a drafty building warm, also review ENERGY SAVINGS PRIORITIES. See BLOWER DOORS & AIR INFILTRATION for a discussion of measuring air leakage in buildings.

Also see HEAT LOSS INDICATORS (where is the building losing heat during the heating season, or gaining un-wanted heat during the cooling season),

and see HEAT LOSS R U & K VALUE CALCULATION for a guide to calculating heat loss (or gain) rates for buildings and building insulation.

1. R-Value is expressed as rate of heat loss per hour per square foot per inch of thickness of material per deg. F - see "R" value definition
   
   at DEFINITIONS of R K U VALUES For some building materials (such as sheet flooring) we give an R-value for a specfic thickness other than the standard 1".
   
   and
   
   at HEAT LOSS R U & K VALUE CALCULATION
   
   
2. Insulation density is expressed in pounds per cubic foot of material
3. Permeability is expressed as the water vapor permeability of the material per inch of thickness. These numbers are most useful to compare one insulating material to another.
4. Absorption is the tendency of the insulation to absorb water in percent by weight. This is important for assessing the risk of mold in some materials
5. Flame Spread is a measure of fire resistance of the material. Use these numbers to compare one insulating material to another.
6. Smoke is a measure of fire safety - that is, the relative amount of smoke produced if the insulation is exposed to flame or combustion
7. Toxicity is a measure of fire safety - that is, toxins given off if the insulation is exposed to flame or combustion.
8. Polystyrene may be in molded or extruded forms and like some other plastic or foam insulations may be in open or closed cell form. (Closed cell foams are more moisture resistant). Polystyrene also is referred to as molded expanded polystyrene (MEPS), expanded polystyrene (EPS), and extruded polystyrene (XPS) - the most common foam board insulation product. MEPS & XPS are used in insulated structural panels and in insulating concrete forms (ICFs).
9. INSULATION IDENTIFICATION GUIDE [web article] Insulation product names in the first table column include links to articles that help identify and provide the properties of each insulating material listed.
10. Open vs. closed cell: Foam insulation densities vary among closed-cell vs open cell forms. Open cell foams are typically about 1/2 lb/cubic foot; Closed cell foams are more dense and rigid, typically about 2 lb/cu. ft.
11. C or Thermal conductance of these materials is the reciprocal of the R-value. C is known only when the k, the thermal conductivity of a material is known. k is the heat transmitted through a 1-inch thickness of homogenous material per square foot per hour when there is 1 degree of temperature change. k= (BTU * inch) / sq.ft. * hour * degF.
12. Air film: This table of R-values does not consider the insulating characteristic of the air film on each side of a surface nor the effects of wind on the air film or on the material itself. Some of these materials are more resistant to wind-caused heat transmission than others.
13. Moisture: Closed cell foams resist moisture uptake (good) but if construction is improper they can trap moisture (bad) leading to rot or mold problems in other building materials.
14. Insects: Exterior foam board on foundations can ease attack by wood destroying insects.
15. Fire & smoke: Foam insulation products present fire-smoke hazards and usually they must be protected with a fire barrier (usually 1/2" drywall).
16. R-Values for wooden log walls WOOD R-VALUES given by the U.S. DOE [PDF] are in error except for square log walls. D-logs and round logs that are given a nominal log thickness, say 6" logs are calculated by DOE as having an R-value of just over 8.
    
    Watch out: This is incorrect for non-square logs because the cross section of the log is 6" only at the log's widest point. A correct assessment of the R-value of a wooden log wall needs to be calculated based on the average wall thickness, considering the variation in thicknesses over the curvature of the logs. Therefore the DOE's value is on the "high" end of the R-value of a log wall.
17. R-Values of uninsulated concrete: Concrete Homes Magazine web search 5/18/2010
18. R-Value for concrete, glass, other materials, Wikipedia web search 5/18/2010 citing Ristinen, Robert A., and Jack J. Kraushaar. Energy and the Environment. 2nd ed. Hoboken, NJ: John Wiley & Sons, Inc., 2006.
19. E-Star Colorado. Energy Saving Calculations. Energy Living Alliance, 2008. Web 05/18/2010
20. U.S. Department of Energy, DOE Handbook, see http://buildingsdatabook.eren.doe.gov/TableView.aspx?table=5.1.3 18 May 2010. The DOE in turn cited these sources
    • ASHRAE, 1997 ASHRAE Handbook: Fundamentals, p. 24-4, 22-5
    • DOE, Insulation Fact Sheet, Jan. 1988, p. 6
    • U.S. DOE, INSULATION TYPES [PDF] table of common building insulation properties from U.S. DOE.
    • Journal of Thermal Insulation, 1987, p. 81-95
    • ORNL, ORNL/SUB/88-SA835/1, 1990
    • ORNL, Science and Technology for a Sustainable Energy Future, Mar. 1995, p. 17
    • ORNL for vacuum insulation panel
21. Wikipedia, web search 5/18/2010 R-Values per Inch
22. EcoHaus UltraTouch cotton insulation batts batts http://www.ecohaus.com/C-121/ultratouch+batts Web search 5/18/2010
23. Icynene product information see http://www.icynene.com/icynene-insulation/ - Web search 5/18/2010
24. ICC Legacy Report ER-2833 - Cocoon Thermal and Sound Insulation Products, ICC Evaluation Services, Inc., Website: icc-es.org - Web search 5/18/2010
25. HomeFoam®, Home Insulation Corp. - see http://www.homefoam.ca/articles/Why_HF.htm - Web search 5/18/2010
    Home Foam® does not contain formaldehyde, fibrous particulate, HFCs¹, CFCs² or HCFCs³ and is a zero-ODP⁴ product. The Saskatchewan Research Council (SRC) advises that even sensitive individuals may take occupancy just 24 hours after application is complete.
26. Air Krete®, Air Krete Inc., P.O. Box 380, Weedsport NY 13166-0380 Keene Christopher, Principal Telephone: (315) 834- 6609, Retrieved 05 Dec 2010, AirKrete® Green Insulation Specifications, original source: http://www.airkrete.com/ Specifications for AirKrete® can be found at http://www.airkrete.com/pdf/072101specification.pdf
27. AirKrete® Water Permeability Coefficient, 03/02/2005, letter provided by AirKrete, retrieved 05 Dec 2010, original source: http://www.airkrete.com/testResults_files/PermRating.pdf
28. Nomaco Insulation, "Calculation of K Value and R-Value, Technical Bulletin TS12-0909", Nomaco Insulation, 3006 Anaconda Rd., Tarboro NC 27886, Tel: 866-876-2684, Website: nomacoinsulation.com, offers this helpful explanation of K values: Quoting:
    
    The actual k-factor is based on the number of BTUs per hour that pass through a one inch (1”) thick by one foot (1’) square section of insulation with a 1°F temperature difference between the two surfaces.
    
    Insulation materials usually have k-factors less than one and are reported at what is called Mean Temperature. To determine the mean temperature, measure the surface te mperatures on both sides of the insulation, add them together and divide by two.
    
    When comparing the insulation value of different types of insulation it’s important to look at the k-factor AND the mean temper ature. As mean temperature rises, the k-factor on some insulation materials also increase. - retrieved 3/23/14, original source: http://www.nomacoinsulation.com/pdf/polyolefin%20faq/TS12%200909.pdf
29. Steve DeBusk, writing on low-e glass vs window films at Buildings.com, retrieved 4/16/2014 original source: , quoting; Low-e window film U-value and emissivity values can range, depending on the type of film.
    
    Standard window films ... U-value and emissivity values vary for standard window films, depending on the type of film, with emissivity values ranging from 0.70 to 0.81,. ... Conventional low-e window film has an emissivity rating of 0.33 ... there are newer low-e window films available with emissivity ratings as low as 0.07
30. "Resistance Values of Structural and Finish Materials", Ira A. Fulton College, Engineering Faculty, 368 CB, Provo, UT 84602 USA, retrieved 2016/10/25, original source: http://cmfac.groups.et.byu.net/jsmith/Lessons/TempSoundControl/R-Values.pdf
    
    Watch out: this PDF of the heat transfer resistance of strucutral and finish materials may in fact have obtained some of its numbers from our own data at this web page: beware of circular reference citations.
31. Dow® TUFF-R™ and Super TUFF_R™ POLYISOCYANURATE INSULATION [PDF] properties, The Dow Chemical Company Dow Building Solutions 200 Larkin Midland, MI 48674 1-866-583-BLUE (2583) Fax 1-989-832-1465 www.dowbuildingsolutions.com retrieved 2020/02/14 original source: http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_09a8/0901b803809a8de7.pdf?filepath=styrofoam/pdfs/noreg/179-07932.pdf&fromPage=GetDoc
32. Awad, Shelly, consultant, Greenhouse glazing options as discussed by greenhousegab.com retrieved 2020/07/07 original source: http://greenhousegab.com/consider-the-r-value/
33. Charley's Greenhouse, "16mm Clear Super 5X-Wall Storm Clear Polycarbonate Sheet", Polycarbonate Store, 17979 State Route 536 Mount Vernon, WA 98273-3269 1 (888)-977-POLY [888-977-7659] service@polycarbonatestore.com retrieved 2020/07/07 original source: http://www.polycarbonatestore.com/16mm-clear-super-5x-wall-storm-clear-polycarbonate-sheet/
34. Co-Ex, 10-Wall Polycarbonate Sheet, 16mm/10X E.S. with a U-Value of 1.7W/m2K, [PDF] 5 Alexander Dr., Wallingford, CT 06492 Tel: (203) 679-0500, (800) 888-5364 E-mail: info@co-excorp.com , Website: www.co-excorp.com retrieved 2020/07/07 original source: http://www.co-excorp.com/pdf_files/10X.pdf
35. Gutex R-values for Ultratherm 50 given as R 6.6 for a 1 15/16" thickness. R-values vary by board thickness. Gutex Ultratherm 160 is 6 5/16" thick and has an R-value of 21.5. More on Gutex is at FIBERBOARD SHEATHING
    - source: https://foursevenfive.com/gutex-ultratherm/ retrieved 2020/11/13
36. Commins, Tav, and J. E. Christian. "R-value of straw bales lower than previously reported." California Energy Commission, URL (consulted April 2003): http://www. buildinggreen. com/news/r_value. cfm (1998).
37. McCULLOUGH, NICHOLAS W. "Drywall product." U.S. Patent Application 12/823,542, filed December 29, 2011.
38. Hassey, Humberto, and L. L. C. MagBoard. ROK-ON SteelStud Thermal Analysis [PDF] (2018). VP Engineering MagBoard LLC, e May 2018
    Abstract:
    
    All wall assemblies use a number of components with varying Rvalue properties. Heat transfer through these materials can significantly impact the overall thermal performance of the walls reducing the effective R-value of the assembly through thermal bridging the insulation layers.
    
    Effective R-value of a wall assembly is not just the sum of the R-value of various components due to the fact of thermal bridging. Metal can be thousands of times better at conducting heat than the typical insulating materials found in a wall,
    
    t herefore the thermal bridge incurred by using steel elements can be substantial if no continuous insulation break of the thermal bridge is provided A finite element analysis of the thermal flux properties of a wall system using regular batt insulation with the ROK-ON Panel System
    
    coupled with different gauge 6” steel studs is studied, The effective R values are calculated and shown.
39. Duton, John E.,, Composite Wall R-Values, Penn State University, e-Education Institute, College of Earth & Mineal Sciences, retrieved 2021/01/24 original source: https://www.e-education.psu.edu/egee102/node/2064
40. R-VALUE of BUILDING MATERIALS [PDF] Alaska Housing Finance Corporation, P.O. Box 101020 Anchorage, Alaska 99510 USA, Tel: 800-478-2432 Website: https://www.ahfc.us/ retrieved 2021/01/24 original source https://www.ahfc.us/iceimages/manuals/building_manual_ap_1.pdf
41. Lawton, Mark, Patrick Roppel, David Fookes, A. Teasdale, and Daniel Schoonhoven. "Real R-value of exterior insulated wall assemblies." All are with Morrison Hershfield Ltd., Vancouver, BC, Canada (2010).
    Excerpt:
    
    Batt insulation for installation between studs is manufactured slightly oversized so that when it is compressed by the drywall it is possible to avoid even small gaps. In the field, air gaps often form at the corners of batt insulation because of defects in installation.
    
    This common defect can allow significantly more heat flow than the rated R-value would suggest as it allows convective loops to form.
42. Insulfoam, EPS vs XPS DATA SHEET [PDF] (2021) Insulfoam Co., Carlisle, Tel: (800) 248-5995 Web: www.Insulfoam.com - retrived 2022/07/15 original source: https://www.insulfoam.com/wp-content/uploads/2021/07/IF-14188-EPS-vs-XPS-Sell-Sheet_07-07-21.pdf
    
    Excerpts:
    Expanded Polystyrene insulation (EPS) is produced through expansion using heat via steam and pentane in a large mold to expand and fuse the resin together.
    
    This process produces a closed-cell structure that contains air. Expanded polystyrene is very versatile because it can be molded and cut into different shapes and can be produced with additives such as pest deterrents.
    
    Extruded polystyrene insulation (XPS) is manufactured using a process of extrusion from polystyrene resin and blowing agents which are extruded into boards.
    
    This continuous process results in a closed-cell structure XPS which contains gases other than air within the closed cells. XPS insulation is typically available in standard dimension square or rectangular boards.
    
    Brands of XPS are generally recognizable by the color of the insulation: green, blue, pink, etc.
43. Teesdale, Laurence Victor. THERMAL INSULATION MADE OF WOOD-BASE MATERIALS: ITS APPLICATION AND USE IN HOUSES [PDF] (1958) Report No. 1740, US Forest Products Laboratory, U.S. Department of Agriculture, Madison 5, Wisconsin, in cooperation with the University of Wisconsin.

X

Y

Z

...

---

---

ADVERTISEMENT

---

---

Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

What is the R-value of a 10mm thick Concrete Skim Coat?

It is quite common to skim a wall with a cement coat (say approx 10mm thick) as a base on which to then apply a finish coat of lightweight plaster.

I can find the R-value for lightweight plaster, but nothing for cement skims applied to vertical walls - everything relates to concrete only (and usually horizontal concrete slabs).

I strikes me that the cement skim layer underlying the plaster must also have an insulating property........ but I cannot find any R-values for thin cement skims applied to vertical walls. Can you help please.....any ideas would be most welcoe.

- Anonymous by private email 2022/05/10

Moderator reply: 10mm concrete has an R-value of about R 0.1

Right on this page at CONCRETE R-Values we give the insulating values of various types and thickensses of concrete.

You'll see our statement that a ypical residential weight concrete 8" wall has an R-value of about R 2.5.

That is, ordinary concrete has an R-value of 0.08 - 0.3125 per inch, depending on various sources and variations in concrete mix.

Using the first data point of R 2.5 for an 8-inch thick wall, that's the high end of the R-value range (and in my opinion optimistic) and would be

R 0.35 per inch.

Since 10mm = 0.3937 inches or about 0.4 inches

The highest-estimate R-value of a concrete skim coat would be R0.35 x 0.4in = R 0.14 - maximum,

and a minimum of

R-0.032 at the lower end of the concrete R-values range.

A plausible guess therefore, at mid-range would put the concrete skim coat R-value at 0.1

...

Help me out by a little education: what use is made of the data when the R- is so low?

I guessed that even a very-low R-value, if over a sufficiently-large area, and with enough indoor-vs-outdoor temperature difference, might be of interest.

Reader follow-up:

Thank you very much for your helpful reply. I always thought the R-value would be quite small, akin to or less than lightweight plaster, but nevertheless I was interested as to what it might be.

I am very happy for this question to be made public, provided that my name, email and any other personal data are kept private. Also, if possible I do not want to be identified as a contributor. But please feel free to publish the question, and the answer.

Your website is incredibly comprehensive and a real find - well done.

...

Although the R-value for a cement skim coat might be small, it is still there.

Everyone would usually factor in a 13mm coat of lightweight plaster if it was present, and use an R-value of about 0.081, and this is in the ball-park of 0.10 which is a plausible average R-value for a 10mm cement skim coat. So I reckoned that if I was taking the plaster coat into account, I may as well account for the cement skim coat too.

The question might well be put, "why bother?" And I think your answer hit the nail on the head. It's because of the large areas of wall that are being dealt with.

In the UK, when domestic houses are bought and sold, a formal Energy Performance Certificate (EPC) has to be produced for the house in question so that the buyer can see what they are letting themselves in for in terms of future energy costs (a hot topic at the moment!).

A larger house might have 400m2 of wall-area and so these smaller R-values add up, even though they might be overshadowed by the insulation in the cavity of the wall which is providing most of the wall's overall R-value. Every little helps, as they say.

How to calculate the U-Value and R-Value of 7 cms thick and 4,4 cms thick plastic bricks

Hello. I'm looking for some advice. I want to know how to calculate the U-Value and R-Value of 7 cms thick and 4,4 cms thick plastic bricks (100% plastic mixing recycled bricks). Heat dissipation of both of them is 62.59% (7 cms) and 33,52% (4,4 cms). Any idea? - On 2022-03-11 by Samuel -

Reply by Inspectapedia Com Moderator (mod) - how to calculate the U-Value and R-Value

@Samuel,

Sure,

Look at the Recommended Articles on this page and you'll see links to HEAT LOSS RATE CALCULATIONS - R, U, & K VALUES R-Value and U-value calculation procedures.

...

Continue reading at HEAT LOSS R U & K VALUE CALCULATION or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see INSULATION R-VALUES & PROPERTIES FAQs - questions & answers posted originally at this page.

Or see these

Recommended Articles

• ENERGY SAVINGS in BUILDINGS - home
• ENERGY USE MONITORING, SOLAR
• HEAT LOSS INDICATORS - where is the building losing heat during the heating season, or gaining un-wanted heat during the cooling season
• HEAT LOSS R U & K VALUE CALCULATION - guide to calculating heat loss (or gain) rates for buildings and building insulation.
• INSULATION CHOICES & PROPERTIES
• INSULATION IDENTIFICATION GUIDE
• INSULATION INSPECTION & IMPROVEMENT - home
• PERM RATINGS of BUILDING MATERIALS

Suggested citation for this web page

INSULATION R-VALUES & PROPERTIES at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING INSULATION

Or use the SEARCH BOX found below to Ask a Question or Search InspectApedia

Ask a Question or Search InspectApedia

Try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.

Note: appearance of your Comment below may be delayed: if your comment contains an image, photograph, web link, or text that looks to the software as if it might be a web link, your posting will appear after it has been approved by a moderator. Apologies for the delay.

Only one image can be added per comment but you can post as many comments, and therefore images, as you like.
You will not receive a notification when a response to your question has been posted.
Please bookmark this page to make it easy for you to check back for our response.

---

 

IF above you see "Comment Form is loading comments..." then COMMENT BOX - countable.ca / bawkbox.com IS NOT WORKING.

In any case you are welcome to send an email directly to us at InspectApedia.com at editor@inspectApedia.com

We'll reply to you directly. Please help us help you by noting, in your email, the URL of the InspectApedia page where you wanted to comment.

Citations & References

In addition to any citations in the article above, a full list is available on request.

---

ADVERTISEMENT

---