This is a program outlining how architects can prevent moisture damage in masonry cavity wall and single wythe CMU construction. If you would like to have a Mortar Net Solutions representative present this program as a live Lunch and Learn program, please email afox@mortarnet.com

1. Presented by

2. Introduction
• It is important that careful consideration be given to each phase of
masonry construction; especially water management.
• By some estimates, 90% of masonry problems in commercial
buildings are water related.
• 40% of masonry problems occurs during the Design and Specification
phase.
• Workmanship contributes to 50% of masonry problems,
Materials contribute only 10%.

3. Upon completion of this course, design professionals
should understand the best techniques and materials
available for dependable masonry water control. The
course includes:
• Moisture Problems inherent within
Masonry Construction
• Types of Flashing
• Mortar Collection Devices for Cavity
Wall & Single Wythe Construction.
• Weeps and Vents
• Moisture Control for Single Wythe
Block applications.

4. How does the Water get in?
• Joints: Inadequately filled or over-sanded mortar joints
(Extreme Acid Cleaning)
• Weep hole/vents: Clogged or omitted
• Flashing: Omitted, improperly installed, or poor quality
• Moisture: Can enter during construction

5. Cavity Wall Construction

6. Cavity Wall Construction
• Cavity Wall Construction.
– The BIA defines a cavity wall as having a continuous
air space .
– The BIA recommends a 2 inch minimum cavity for
proper drainage and airflow.
– The BIA Technical Note 21A allows rigid insulation to
occupy one-half of the 2-inch cavity.
– Source: BIA

7. Flashing
What is Flashing?
• Flashing is a membrane installed within a
masonry wall to either prevent moisture
infiltration, or divert moisture which does
penetrate the wall, back to the exterior of
the building.

8. Types of Flashing
Advantages/Disadvantages
MATERIAL ADVANTAGES DISADVANTAGES COSTS
Stainless Steel Durable. Difficult to bend, $18.00 per lf
High installation costs,
Must be preformed at factory,
Usually requires steel
workers for installation
Cold-rolled Copper: Durable, flexible. May leave stains $ 13.50-$16.20
Lead-coated Copper: Easier to form Lead content
Does not stain
Galvanized Widely Accepted Deteriorates in acidic $14.40 per lf
environment
Source: Masonry Magazine 2002

9. Types of Flashing
Advantages/Disadvantages
MATERIAL ADVANTAGES DISADVANTAGES COSTS
Copper Laminates: Easier to form and join May tear $13.50 per lf
than metals Asphalt degrades in sunlight
EPDM Not affected by UV rays, Requires adhesives $7.50 per lft.
(man-made rubber) Tear and puncture resistance More difficult to work with
than rubberized asphalt, resulting
in higher labor costs.
Good corrosion resistance
Rubberized Flexible at low temperatures Affected by UV rays $6.80 per lf
Asphalt Flashing Excellent tear/puncture (including
System. Self sealing around drip edge)
small holes;
Polyvinyl Chloride Not recommended for
through-wall flashings (BIA)
Source: Masonry Magazine 2003

10. Flashing Drool

11. Mortar Collection Systems

12. A Functional
Mortar Collection Device
• Designed to break
up mortar
droppings above
the weep holes.
• Provide a means for
water to travel to
the base and out the
weeps.

13. Masonry Drainage System
Shape:
•Does it break up mortar droppings or merely raise
damming?
•Does it fill the entire cavity?

14. Drainage Methods:
Which is most functional?
Pea Gravel
Nothing
Straight Strip
Dovetail

15. Panelized Flashing System
Pre-Formed
Corner Boots, Metal Corners
& End Dams
Are available for “perfect corners
every time”
5-1/2 ft. Panels of
PRE-CUT FLEXIBLE FLASHING*
All main components are factory assembled
onto easy-to-mount flashing panels
Built-In
NO-CLOG DRAINAGE MAT
Lets water pass, unobstructed to Weep Tabs
Built-In
TERMINATION BARS
With pre-drilled holes that allow quick, one-person
installation
Clearly Specified
LAP JOINTS
Enforces complete &
secure coverage
Built-In
STAINLESS STEEL
DRIP EDGE
Releases moisture away
from building
Built-In
NO-CLOG WEEP TABS
Delivers moisture to the
outside of the building
*Standard Flashing Membrane is an 18-inch, 40-mil polymeric, reinforced, UV stable
membrane with Elvaloy®KEE

16. Installing Panelized Flashing

17. Installing Panelized
Flashing

18. Completed Panelized
Flashing Installation

19. Weep Vent Systems

20. What are Weep Holes?
Openings that prevent water from accumulating
behind or within a wall.

21. BIA recommended
spacing of Weep Holes
Spacing Recommended Maximum
(Center to Center)
Wick Material 16 in.
Open Head Joints 24 in.
Vents 24 in.
Tubes Not recommended (BIA)

22. Weep Design
• BIGGER is Better (air flow)
• Fill the open head joint
• UV Stable
• Color stable
• Flame resistant
Installed
Weep Vents
Mesh Weep
Vents
Multilayer Weep Vents

23. Cavity Wall Failure Prevention
• Good design
• Quality workmanship
• Proper materials
• Mortar collection device
• Weep holes protected from insects and debris

24. Single Wythe Construction

25. Single Wythe Construction
• Single-Wythe Block Wall Construction is popular because
it offers:
– Significantly lower cost per lf than cavity wall
construction or tilt up
– Faster build times
– A wide variety of texture and colors
– A high degree of design and build flexibility
– Proven durability
– Wide acceptance by architects, builders, building
owners

26. Concrete block walls are porous
• Porosity allows water infiltration.

27. Strip-style flashing system with
stainless steel drip edge for
single-wythe C.M.U. walls

28. Block Net
Stainless steel
flashing strip Mesh drainage mat
Mesh weep tabs

29. Stainless steel strip-style flashing system

30. Stainless steel strip-style flashing system
Outside face of wall

31. Single Wythe Drainage System
Visible drip edge
Finished C.M.U wall with strip-style flashing system

32. Embedded Pan Flashing System
for Single-Wythe C.M.U. Walls
Water collection pans
Weep spouts
No visible drip edge

33. Embedded Pan Flashing System
Mortar Dropping Collection Mesh

34. Key Problems in Masonry
• Efflorescence:
Occurs when
moisture drives
minerals
deposited in
masonry to the
face
of the unit.

35. New Construction bloom
It takes approximately one month per
inch thickness for a wall to dry after
the roof and air are operational

36. Efflorescence on a Parapet Wall

37. Efflorescence

38. Mortar Damming
• The biggest problem in cavity wall construction is trapped moisture within the
cavity
• Mortar damming traps moisture
Office building in Chicago, IL

39. Spalling
• Occurs when water trapped in
the wall freezes
• Water expands 9% as it
freezes
• Pressure from the expanding
water can fracture brick,
block, and stone

40. Steel Stud Failure
Moisture in the cavity
can cause rust and
damage to steel
framing components.
2 year old building in New York
City
Picture provided by Michael Gurevich,
New York City Brick Works

41. Cavity Wall Flashing Failure
Jackson, MS Hospital (2 years old)

42. Cavity Wall Failure
U.S. Postal Training Facility
Pictures provided by Jerry Combs

43. Mold

44. Mold is the ultimate recycler
It undoes what plants do.
It turns plants back into carbon
dioxide and water.
Mold destroys whatever
it grows on.

45. MOLD
Mold requires:
• Oxygen
• Moderate temperature
(40° to 100°F)
• Food Source: cellulose (wood,
dust, paper, drywall, adhesives,
ceiling tiles, insulation, paint,
plywood, cardboard)
• Moisture: high relative
humidity (standing water,
leaks, floods, condensation)
Picture provided by Rob Poitevent, Vintage Sales

48. I was shocked at how fast
it grows. You can't
breathe. It's like one of
those old Saturday
afternoon scary movies,"
said Sharon Taylor from
Southtrust Bank.
October 8, 2004
Source: Boca Beacon

49. Not all mold is bad.
Mold is everywhere!
It is on our hands and face.
Mold helps digest food.
Mold (Kibe) is injected into rice to
make Sake!

50. There are over 100,000 different
types of mold.
We need to be concerned about
four of them.

51. Mold ##11
Black Mold (Stachybotrys)
Produces toxins that can be lethal.

52. Mold ##22
Penicillium
Causes Pneumonia and
Hypertension

53. Mold ##33
Cladosporium
Found mostly outdoors
Causes allergies/asthma
attacks.

54. Mold ## 44
Aspergillus
Stuff found between your
toes.

55. Mold will continue to be a growing
problem.
To date asbestos law suits have totaled
20 billion dollars
Source: Independent Insurance Council

56. The Super Fund
26 Billion over the last 23
years!
Source: Independent Insurance Council

57. Mold-related Costs:
73 billion dollars/year in health
care and building remediation
Sources:
US Environmental Protection Agency
www.gotmold.ca

58. Mold Insurance
Environmental Insurance is
available; however there are only
300 agents out of 500,000 that
understand environmental
insurance.
Source: Independent Insurance Council

59. Mold Lawsuit
Owner sues contractor
-Contractor sues Architect and
Sub contractor.

60. Prevention

61. Since mold requires water to grow,
it is important to prevent moisture
problems in buildings.

62. Some moisture problems in
buildings have been linked to
changes in building construction
practices during the 1970s, 80s,
and 90s.

63. Some of these changes have
resulted in buildings that are
tightly sealed , but may lack
adequate ventilation, potentially
leading to moisture buildup.

64. Conclusion

65. Quality Masonry Design
Will Stand the Test of Time

66. Thanks for attending.
This ends the AIA/CES presentation.
Presented by