The document provides an introduction to air barrier systems, which control air leakage and moisture movement within building envelopes. It discusses the types of moisture movement that can occur and potential issues with uncontrolled moisture. It also outlines different product types for preventing moisture infiltration and design options. The document emphasizes that a successful air barrier installation requires addressing transitions, penetrations, substrate preparation, and installation sequencing.

1. INTRODUCTION TO AIR BARRIER
SYSTEMS:
CONTROLLING AIR LEAKAGE AND MOISTURE
MOVEMENT
Presented by:
__________________
email@wrmeadow.com

2. Who We Are
• Est. 1926 in Elgin, IL
• Single family owned and operated
• Continued growth to bring regional
manufacturing to all points in North America
• 12 facilities in North America (2 in Canada)

3. The Meadows’ Family of Products
Expansion Joint Materials
Concrete Restoration
Construction Liquids
Joint Sealants
Building Envelope
Blue Ridge Building Products
Soundproofing & Insulation Board

4. This program is registered with the AIA/CES for continuing professional education. As
such, it does not include content that may be deemed or construed to be an approval
or endorsement by the AIA of any material of construction or any method or manner
of handling, using, distributing, or dealing in any material or product. Questions
related to specific materials, methods, and services will be addressed at the
conclusion of this presentation.
W. R. MEADOWS is a Registered Provider with the American Institute of Architects
(AIA) Continuing Education Systems. Credit earned on completion of this program
will be reported to CES Records for AIA members. Certificates of Completion for non-
AIA members are available on request.

5. THE BUILDING ENVELOPE
The Science of Moisture Control considers the entire
building envelope.
Under Slab, Below Grade, and Above Grade Systems
must work together to provide complete protection for
our structures.

6. Objectives
• Define types of moisture movement within the building envelope,
including liquid, vapor, or airborne moisture
• Identify potential issues with uncontrolled moisture movement
• Identify product types associated with preventing moisture infiltration
• Identify design options to prevent moisture movement.
• Discuss installation requirements for a successful air, water, and vapor
barrier installation

8. High Performance Building
• “Can be defined as a building
that integrates and optimizes on
a life cycle basis all major high
performance attributes, including
energy conservation,
environment, safety, security,
durability, accessibility, cost-
benefit, productivity,
sustainability, functionality and
operational considerations”
- Energy Independence
and Security Act of 2007

9. High Performance Building
• “Can be defined as a building
that integrates and optimizes on
a life cycle basis all major high
performance attributes, including
energy conservation,
environment, safety, security,
durability, accessibility, cost-
benefit, productivity,
sustainability, functionality and
operational considerations”
- Energy Independence
and Security Act of 2007

10. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

11. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

12. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

13. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

14. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

15. Moisture Movement
• Hydrologic Cycle
• Gravity
• Capillarity
• Vapor Diffusion
• Air Transport
• Dew Point

16. Moisture Movement by Air
70-90% of the moisture is moved by air transport.
10-30% of moisture is moved by vapor diffusion.

17. Air Leakage
• Air flows through gaps and cracks in the
building envelope.
• Uncontrolled air leakage causes heat loss as
warm air is displaced through the envelope by
colder air from outside.
• Air leakage of warm, damp air can lead to
condensation within the envelope (interstitial
condensation), which reduces insulation
performance

18. Air Flow
• Wind Pressure
• Stack Pressure
• Mechanical Pressure

19. Air Leakage
• In theory, fairly easy to control
• Stop the air flow…
Fill any gaps or cracks
• In practice, easier said than done

20.  The Function of the Building
 Comfort and Health of the Occupants
 Increase the Life Cycle of the Structure
 Efficient Systems Reduce Energy Waste
 According to the AIA, water infiltration
is a leading factor in post construction
litigation*
Why Stop the Air Flow through the
Building Enclosure System ?

22. Why Stop the Air Flow through the
Building Enclosure System ?
• Air flow affects the location of the dew point.
• Air leakage causes the HVAC system to use extraneous energy to
maintain desired temperatures and humidity levels.
• Air flow is a vehicle by which sound travels.
• Air flow is a vehicle by which particulate matter travels.
• Air flow is a vehicle by which odors and gaseous substances travel.

23. Air Control Layer
“Air Barriers cannot be dealt with without understanding that they
are part of a wall assembly”
N.B Hutcheon’s CBD-48 – Requirements of Exterior Walls

24. Building Enclosure Basics
• Cladding
• Structural Component
• Control Layers
– Water Control Layer
– Air Control Layer
– Vapor Control Layer
– Thermal Control Layer

25. Building Enclosure Basics

26. Where is the Air Barrier Located?

27. Essential Elements of an Effective Air Control Layer
Airtightness
Waterproofing Capabilities
Continuity
Durability
Structural Integrity

28. Air Barrier System
Air Barrier Assembly
Air Barrier Assembly
Air Barrier Material
Air Barrier Material
Air Barrier Material
Air Barrier Material
Layers of an Air Barrier System

29. Layers of an Air Barrier System
Air Barrier System
Air Barrier Assembly
Fenestration AssemblyFlashings
Air Barrier Membrane
Mastics, Sealants
Joint Sealants
Glass
Remember! The Air Barrier System includes Under Slab, Below Grade, Above Grade, and Roof.

30. Types of Air Barrier Materials
Thin MilStandard
Thickness
VAPOR
IMPERMEABLE
VAPOR
PERMEABLE
FLUID APPLIEDSPRAY FOAM
MECHANICALLY
FASTENED
SHEET
VAPOR
IMPERMEABLE
VAPOR
PERMEABLE

31. Do You Need a Vapor Barrier
in the Vertical Wall Assembly?

32. Short Answer, No.

33. Types of Air Barrier Materials
Self-Adhered Sheet Materials

34. Types of Air Barrier Materials
Fluid Applied Materials (Non-Foaming)

35. Types of Air Barrier Materials
Mechanically Fastened: Insulating Board Stock, Integrated Sheathing

36. Types of Air Barrier Materials
Mechanically Fastened Membranes (Film Materials)

37. Types of Air Barrier Materials
Foaming Fluid Applied

38. Which of these is not an Air Barrier Material?

39. Air Barrier Components
• Transition Membrane: Where backup is
interrupted (joints) or where there will be
movement in the substrate
• Tape (mesh or peel/stick): For fluid‐applied
products, the joints of the sheathing boards
must be filled or taped, and the mortar
joints of masonry units must be filled and
cut off flush.
• Primers/Adhesives: For proper adhesion of
some self‐adhering sheet membranes
• Mastic: Seal edges and ends.
• Termination Bar: Mechanical attachment
• Joint Filler and Patching Compounds

40. Product Considerations
• Product Durability (Track Record, History)
• Local Code Requirements
• Cost (Labor, Materials, Time)
• Manufacturer Support (Design & Installation)
• Compatibility Between Materials
• Project & Site Conditions
• Rainfall Resistance (Scheduling)
• Puncture Compensation (Self Gasketing)

41. Design of an Air Barrier System
• Keep it simple!
• Decide which layer provides the air
barrier and maintain continuity.
• Minimize different envelope types, if
possible.
• Pay attention to the details and
sequencing of all transitions.
• Minimize penetrations, if possible.
• Where penetrations are unavoidable,
develop details that are clear and
simple to construct

42. Specifications Considerations
• Performance Reports –
How is the product or assembly being tested?
Verify the testing results are apples-to-apples
• Proprietary or Performance Based -
Be clear regarding design intent
Avoid confusion in the field
• Every project will have a “best fit” system
No product is one size fits all.
• If different manufacturers are specified for the
same control layer, evaluate compatibility.

43. Design – Plan Review
• Air barrier is usually depicted as a single
line on the drawings, then left to the
builder to achieve continuity
• Rarely are details included that indicate
products to be used, sequencing or
compatibility
• By the time the inspector arrives,
installation has begun and corrections
result in change orders
• Dedicate a plan review for the air barrier
system

44. Design – Tricky Parts
Transitions:
• Roof‐to‐wall
• Foundation‐to‐wall
• Wall‐to‐door/window
• Wall‐to‐curtain wall
• Relieving angles, joints
• Mechanical/electrical/structural
penetrations
• Differing cladding or backup

45. Pre-Installation Meeting
• Discuss details for airtight transitions and
connections
• Discuss sequencing of materials and trades
• Define expectations
(Substrate prep and quality of installation)
• Ensure that the materials being joined
together are compatible
• Include All Trades that Touch the Air Barrier
• Mock-ups
– Quality Control
– Compatibility
– Special Conditions

46. Installation Considerations
• Number of joints
• Substrate condition/preparation
• Building Location
• Environment/Climate
• Installation Sequence
• Coordination with Details of Other Systems
• Number of Penetrations
• Rough Openings

47. Substrate Conditions
• Substrate moisture
• Glass Faced Gypsum
• Surface profile
• Control joints
• Wood—beware of staples
• Sheathing joint treatments

48. Connections
• Roof, wall, windows, doors,
foundations, floors over crawl
spaces, ceilings under attics and
across building joints must be
flexible.
• Must withstand building movement
due to thermal, seismic, moisture
and creep.
• Joints must support the same air
pressures as the air barrier
material without displacement

49. Roof – Wall Connections

50. Penetrations

51. Fasteners

52. Fasteners

53. Shelf Angle

54. BaseofWall

55. Sheathing Joint
Treatment

56. Expansion Joint Treatment

57. Rough Openings – Jamb & Sill

58. Rough Openings – Window Head

59. Rough Openings – Self-Adhesive

60. Rough Openings – Liquid Flashing

61. Construction Damage – Workmanship

62. Poor Workmanship – Installation Inspections

63. UV Exposure - Sequencing

64. Summary
• Air barriers are an essential part of a building’s energy savings and durability
• Select materials and systems based on project requirements and climate
• Air barrier installation needs to be addressed during the design stage and all
factors need to be considered
• Performance of an air barrier system is dependent on the details
• Consider materials and systems that save time or improve installation

65. This concludes the credit portion of the program for The American Institute of Architects Continuing Education System.
Questions?
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