AA2 Vapor Shield

Reflective Insulation for Masonry Walls

AA2 Vapor Shield Reflective Insulation for Masonry Walls

Fi-Foil's AA2 Vapor Shield is a multi-layer reflective insulation intended for use on furred-out masonry walls. The inside layer is aluminum foil. The outer layer is natural kraft paper coated with polyethylene, internal expanders separate the paper from the foil creating a 3/8" reflective air space. When installed on furring strips spaced 16" or 24" on center, a second reflective air space is formed. This air space is dependent upon the thickness of the furring strip selected. AA2 Vapor Shield is available in Standard & High-perm versions or perforated for applications not requiring a vapor retarder.  AA2 is also available with either a staple or tape-tab for wood and metal framing respectively. 


  • Masonry Wall Insulation - Installation is simple, quick and easy - AA2 Vapor Shield by Fi-Foil
  • Masonry Wall Insulation - Face Stapled - Installed View
  • Insulate masonry walls with Fi-Foil's AA2
  • Masonry Wall Insulation - Installation is simple, quick and easy - AA2 Vapor Shield by Fi-Foil
  • Masonry Wall Insulation Columbia Fi-Foil AA2 Vapor Shield Vapor Retarder
  • Insulate masonry walls with Fi-Foil's AA2

Product Key Specs

Furring/Stud 16” O.C. 24” O.C.
Width Expanded 17.5” 25.5”
Diameter 10” 8”
Lineal Footage 375’ 250’
Coverage 500 sq. ft. 500 sq. ft.
Weight 21 lbs. 19 lbs

Product Test Data

Test Method Description Results
Perforated Non-Perforated
ASTM E96 Water Vapor Permeance 8.67 0.802
ASTM E84-94 Flammability Flame Spread Rating 45 45
Smoke Developed Rating 10 10
National Fire Protection Association Rating Class B Class B
ASTM D3310 Corrosivity N/ANone
ASTM C1244/Section 9 Adhesive Performance Bleeding N/ANone
PliabilityNo signs of cracking or delaminationNo signs of cracking or delamination
ASTM C1338 Mold & Mildew N/APass
ASTM C1371 Foil Emittance0.0340.034

Need an Effective Insulation Solution for Masonry Walls?

See how AA2 Vapor Shield can enhance your building envelope


Compliance and Approvals: 

Meets ASTM C-1244 Standard Specification for Reflective Insulation
Meets International and Florida Building & Energy Code Requirements
See IAPMO ES Report Number 0291

What Our Clients Are Saying

Since the building was built in 1926, our options for insulating the exterior block walls were limited.  We also faced the daunting challenge of insulating the roof and/or attic.  Fi Foil donated a radiant barrier shield for the roof and our...

Sanford, FL

Project Profiles

AA2 Vapor Shield
Project Information: General Contractor: Gables Construction Inc, Boca Raton, FL Insulation Contractor: C. Q.... Read More


Probably not. The change from the standard version of AA2 Vapor Shield and VR Plus Shield to the Hi-Perm version only impacts the R-value by 0.1, so it has little, if any, effect in the overall load on the house. The overall point total should not change. However, the Florida Energy Code Form must indicate the correct R-value for inspection purposes.

As building envelopes are getting tighter, building scientists, energy centers and research organizations are suggesting that insulation products and facings used in hot humid climates have higher perm ratings for increased water vapor transmission. Fi-Foil's Hi-Perm versions are designed to meet or exceed these recommendations.

A water vapor retarder may or may not be part of the design depending on the climate zone and the other building components used in that particular section of the building envelope. If air containing water vapor is allowed to come in contact with a cold surface, then condensation will likely occur. Water vapor transmission can also occur even if the building envelope is air sealed or has an effective and properly installed air barrier.  Some insulation systems should include a water vapor retarder and some should allow vapor transmission.  Building codes and climate zones generally dictate the use of a water vapor retarder -- in short, the envelope is a system and the use should be carefully considered by the building designer.


Reflective insulation has little effect on heat transfer by conduction through the air between hot and cold surfaces.  Air with an R-per-inch of 5.6 is an excellent insulator when radiation and convection are controlled.  The installation of reflective insulation in an enclosed space reduces thermal radiation to near zero.  When the reflective insulation is installed to subdivide an air-filled region then convection is also reduced.

Yes. The ASHRAE Handbook values are a subset of data from the National Bureau of Standards (NBS).

Reflective insulation is one or more low emittance surfaces installed in an enclosed air space. The more layers within the air space, the better the performance. Reflective insulation in a wall system can be compared to a double or triple pane window with low-e surfaces. Triple pane windows with low e surfaces perform better than a triple pane window without low e surfaces because of the reduction of radiation (low emittance) across the air spaces.  

Air inherently has an R-per-inch value of 5.6, and is an excellent insulator when radiation and convection are controlled. The ASHRAE Handbook has tables with values for various enclosed air spaces (0.5”, 0.75”, 1.5”, 3.5”, etc.) with high emittance surfaces (0.82 for common building materials) and values for air spaces with low emittance surfaces facing the enclosed air space (0.05 for low emittance materials like aluminum).  Simply put, adding a low e material makes the enclosed air space perform better. A multilayer reflective insulation system in a wall cavity improves this system by further reducing radiant heat transfer and adding additional “panes”, a two layer reflective insulation could be compared to a double paned window; a three layer to a triple pane window, and so on..  

The installation of reflective insulation in an enclosed space reduces thermal radiation to near zero. When the reflective insulation is installed to subdivide an air-filled region then heat transfer by convection is also reduced. Fi-Foil has single layer, two layer, three layer and even honey-comb layer reflective insulation products for various building applications, each with different performance levels and attributes for the particular application. These products also work very well with other types of mass insulation as hybrid systems by using the best attributes of each of the technologies (e.g. spray foam is great for air sealing and can have a high R--value per inch of thickness --  fiberglass and cellulose is an inexpensive material to reduce convection in the cavity). In some wall systems, especially wall cavities larger than 1.5”, a combination of reflective insulation with one or more of these mass insulation products, addresses all the modes of heat transfer -- often more cost effectively than one of the technologies used alone.


International Association of Plumbing and Mechanical Officials
Spray Polyurethane Form Alliance
Florida Green Building Coalition
South Face
Earth Craft
ICAA logo
NAHB logo