1. 11. MASONRY LOADBEARING WALL CONSTRUCTION

2. Chapter 10 Masonry Loadbearing Wall Construction

3. 11.1 MASONRY LOADBEARING WALL CONSTRUCTION - OVERVIEW
11.2 THREE TYPES OF WALL CONSTRUCTION
11.3 DETAILING OF MASONRY WALLS
11.4 TYPES OF THERMAL INSULATION FOR MASONRY WALLS
11.5 MOVEMENT JOINTS IN BUILDINGS
11.6 OTHER SPECIAL PROBLEMS

4. 11.2 THREE TYPES OF WALL CONSTRUCTION
Reinforced or Non-reinforced wall - Non-reinforced walls cannot carry high stresses and are generally used as parapet walls; sometimes buildings, of 16 story heights, have been built with non-reinforced masonry - Reinforced walls are reinforced with vertical and horizontal steel reinforcements and are less thick
Composite masonry walls: Usually constructed with an outer wythe of stone or facing brick and a back up of hollow concrete block masonry - The two wythes are bonded together by steel horizontal joint reinforcements or by headers from the outer wythe that penetrate the back up wythe
Cavity walls: Since exterior walls must resist water penetration and heat transfer, these walls are built with internal cavities - Masonry cavity walls consist of an inner, structural wythe and an outer wythe of masonry facing - These two are separated by a continuous airspace that is spanned only by corrosion-resistant metal ties that hold the wythes together - Cavity walls prevent water from reaching the interior by interposing the cavity between outside and inside wythes of the wall - When penetrating moisture reaches the cavity, it goes down and is caught by a thin, impervious membrane called flashing and drained through weep holes to the exterior

5. Masonry Wall Types Reinforced or Un-reinforced
Reinforcing Increases Load Carrying Capacity
Uses: Low Rise Construction, Foundations
One Type or Composite Masonry Walls
Composite; Two Wythes of Different Material
Typ. - CMU & Brick
Solid or Cavity Walls

6. Reinforced Masonry Walls
Reinforcing increases Loadbearing Capacity

8. Reinforcing placed in CMU cells and cells filled with concrete
Reinforcing placement determined by structural designer
Cell Reinforcing

9. 11.3 DETAILS OF MASONRY WALLS
Flashing and weep holes: A flashing is a continuos sheet of impervious material that is used as a barrier against the passage of water, into the building - Weep holes drain water from the cavity to the exterior
External flashings: Used to prevent moisture from penetrating the roof edge to wet the masonry wall, at the intersection of roof and the parapet wall - Uses a base flashing and counter flashing to achieve the purpose - Roof membrane becomes the base flashing; counter flashing comes from the outer wall to cover the base flashing - Should be turned in 8” into the wall to prevent water penetration
Internal flashings: Used to catch the water that has penetrated the outer wall and to drain it through weep holes to the exterior - Internal flashings should be placed at the bottom of the wall cavity and at every location where the cavity is interrupted; at heads of windows and doors, at window sills, at shelf angles, and over exposed spandrel beams - Should be accompanied by a weep hole - Should be turned up 6” to 8” at the interior face of the wall and penetrate at least 2” into the back up wythe - Outside the wall, flashing should be carried at least 3/4” beyond the outside face and turned down at 45o angle

10. 11.3 DETAILING MASONRY WALLS (Cont’d)
Weep holes should be placed at every 24” c/c horizontally - Min. diameter for a weep hole is 1/4” - Made by inserting a short of rope laid in the mortar joint and later pulled out - Plastic tube and metal accessories should be provided to prevent insects from entering the cavity
Material for flashing: Made of sheet metal, UV resistant plastics, elastomeric compounds, or composite materials - Galvanized steel is unsuitable but stainless steel and copper are suitable; aluminum and lead are unsuitable

11. Cavity Walls Common Construction for Exterior Walls Insulating Value
Reduced Weight
Drainage

12. Cavity Wall Construction
Inner Wythe or support wall
Air Space (Insulation & Drainage)
Outer Wythe of Masonry
Masonry Ties to hold the Wythes together

13. 11.4 TYPES OF THERMAL INSULATION FOR MASONRY WALLS
Thermal Insulation of Masonry Walls: A solid masonry wall is a poor insulator - Solid masonry wall is massive and as such absorbs and stores heat during day and gives up during night; but in regions of sustained cold weather measures must be taken to improve the insulating qualities of masonry walls
Three different modes of insulation used - (i) Insulation on the outside face with EIFS (exterior insulation and finish system), which consists of panels of plastic foam that are attached to the masonry and covered with a thin, continuous layer of polymeric stucco reinforced glass fiber mesh - Masonry is completely covered with stucco - Disadvantage is that this stucco is easily dented and EIFS is combustible

15. Masonry Veneer Anchors

23. Masonry Flashing External Flashing Prevents Moisture Penetration Types
Material
External Flashing
Prevents Moisture Penetration
Types
CAP FLASHING -
TOP OF WALLS
EDGE OF ROOFS
COUNTER FLASHING
WALL / ROOF INTERSECTION
OFTEN TWO PIECES - ONE IN WALL / ONE ATTACHED
Material
SHEET METAL
COPPER SS
PLASTICS & COMPOSITES

24. Internal Flashing Through Wall (Concealed) Flashing Collects water
Drainage Through Weeps
Placement
“Through Wall” (Concealed) Flashing
CONTINUOUS SHEET OF
COPPER, PLASTIC, RUBBER/BITUMINOUS
ATTACHED TO BACKUP WALL & RUN THROUGH TO THE OUTSIDE OF THE MASONRY
Collects water
WATER THAT HAS PENETRATED WALL
ALLOWS IT DRAIN THROUGH “WEEPS”
ACCOMPANIED BY WEEPS
Drainage Through “Weeps”
PLACED 24 TO 32 in o.c.
ROPE, PLASTIC, METAL (ALSO CAN JUST STOP MORTAR)
> 1/4 IN.
Placement
@ BOTTOM OF WALL CAVITY
@ INTERUPTIONS OF CAVITY
OVER DOORS / WINDOWS
WINDOW SILLS
SHELF ANGLES -

26. Shelf
Angle

27. Dampproofing & Flashing

28. Flashings over Wall Openings

29. 11.4 TYPES OF THERMAL INSULATION FOR MASONRY WALLS
Thermal Insulation of Masonry Walls: A solid masonry wall is a poor insulator - Solid masonry wall is massive and as such absorbs and stores heat during day and gives up during night; but in regions of sustained cold weather measures must be taken to improve the insulating qualities of masonry walls
Three different modes of insulation used - (i) Insulation on the outside face with EIFS (exterior insulation and finish system), which consists of panels of plastic foam that are attached to the masonry and covered with a thin, continuous layer of polymeric stucco reinforced glass fiber mesh - Masonry is completely covered with stucco - Disadvantage is that this stucco is easily dented and EIFS is combustible

30. 11.4 TYPES OF THERMAL INSULATION FOR MASONRY WALLS (Cont’d)
Insulation within the wall: If the cavity in a wall is made sufficiently wide, the masons can insert slabs of foam insulation against the inside wythe as it is built; the overall width of cavity must be adjusted so that the net width of air space is at least 2” - the hollow cores of the cavity wall can be filled with loose granular insulation
The inside surface of the masonry wall is insulated, by attaching plastic foam to the wall and applying plaster directly to the foam, or attaching wood/metal furring strips to the inside of the masonry wall with masonry nails - Presence of furring strips creates a space in the wall in which the electrical wiring and plumbing can easily be concealed

31. Thermal Insulation Outside Face (typically EIFS) Within the Wall
In the Cavity or
In the Hollow Cores
On the Inside Face

32. Insulation in CMU cells
Insulation in Cavity
External Insulation
Insulation in Cavity

33. Insulation being installed in the cavity

34. Masonry Construction Masonry and Wood Masonry and Steel
Masonry and Concrete

35. CMU Masonry with Joist & Metal Decking

36. CMU with Precast Concrete Decking

37. MPE Rough-In Rough-in Electrical Plumbing HVAC Electrical Rough-in
WALL OUTLETS, SWITCHES
“BUILT INTO” WALL
HORIZONTAL - SLEEVES
Plumbing
NOT BUILT INTO WALL (COPPER, CI, PVC)
SLEEVES FOR HORIZONTAL PENETRATIONS
HVAC
TYPICALLY NOT BUILT INTO WALL
MAY REQUIRE FIRE DAMPERS
Rough-in
Electrical
Plumbing
HVAC
Fire Damper

38. Electrical Roughin

39. 11.5 MOVEMENT JOINTS BUILDING
Building materials and building experience small displacements continuously - Many of these motions are cyclical and never-ending - All materials shrink as they grow colder and expand as they grow warmer, each material doing it at its own characteristic rate - All these motions or displacements are small in magnitude, but they occur in every building - If they are ignored in design, they can tear the building apart, causing cracking of brittle materials
These small motions are accommodated by:
- Strengthening of structures so as to resist the expansion stresses
- Providing of movement joints
- Construction joints
- Structure/Enclosure joints - Sealant joints at the top of an interior partition
- Surface divider joints
- Control joints
- Expansion joints

40. Expansion & Contraction
Structure Movement, Masonry Changes
Expansion Joints
Within Masonry Wall
Two-way Movement
@ Change in Thickness, Height, or Openings
Isolation Joints
Structure Movement, Masonry Changes
WEIGHT / LOADING
MASONRY - THERMAL EXPANSION/CONTRAC
MUST PROVIDE FOR - OR CRACKING
Expansion Joints
Within Masonry Wall
Two-way Movement
@ Change in Thickness, Height, or Openings
JT REINFORCING / MORTAR MUST BE INTERUPTED
Isolation Joints
@ DISSIMALR MATERIALS

41. Expansion Joint
Weep Holes

42. Expansion Joint Material

43. 11.6 OTHER SPECIAL PROBLEMS
Expansion and contraction: Due to temperature and moisture content - Should be accounted for in the design
Efflorescence: A fluffy white powder, that sometimes appears on the surface of a brick, stone, or concrete block wall - Consists of one or more water soluble salts that migrate to the surface - Can be prevented by proper choice of masonry units
Mortar joint deterioration: Water running down a masonry wall tends to accumulate at mortar joints - Due to freeze and thaw cycles the mortar in the joints expands and contracts alternatively and deteriorates - Weather-resistant mortar must be used to prevent deterioration
Moisture resistance of masonry: Moisture resistance of masonry units must be specified to minimize water absorption - Flashing and weep holes must be provided - Exterior wall must be coated with stucco or paint - Below grade masonry should be parged with two coats of type M mortar, 1/2” thick - The exterior wall must be coated with damp-proofing compound

44. 11.6 OTHER SPECIAL PROBLEMS (Cont’d)
Cold and hot weather construction: Special precautions are necessary to prevent mortar freezing before curing is complete - Keep masonry units dry - Protect them from freezing before use - Use type 30 cement (high early strength) and warm water to produce mortar at a optimum temperature - Mix mortar in small quantities - Protect the wall from wind, as the mason builds it - Protect against freezing for at least three days - Try to avoid chemical accelerators and “anti-freeze” admixtures since they are harmful to mortar and reinforcing steel - In hot weather, dampen the masonry units before laying them in place - Also keep the masonry units and mortar ingredients in shade before use

45. Other Special Problems
Efflorescence
Joint Deterioration
Moisture Penetration
Hot & Cold Weather Construction
Efflorescence
FLUFFY WHITE SURFACE
WATER SOLUBLE SALTS
CAN BE CLEANED
WATER INFILTRATION
Mortar Joint Deterioration
FREEZE THAW
DELAY BY PROPER JOINT PROFILE
TUCK POINTING - RACK OUT AND REPLACE
Moisture Penetration
COVERED
PROPER JOINTS AND INSTALLATION
COATINGS, MATERIAL SELECTION
CAVITY CONSTRUCTION
Cold Weather Construction
MORTAR CAN’T FREEZE UNTIL CURED
ENCLOSURES (HEATED)
ADMIXTURES TO SPEED SETTING TIME
Hot Weather – Mortar may dry out excessively

46. Efflorescence

47. Efflorescence

48. Masonry and the Codes Masonry often used as a fire separation wall
Used with Steel and Concrete Decks - Type 1&2