Presentation is loading. Please wait.

Presentation is loading. Please wait.

A Technical Review of Proper Masonry Detailing Matthew A. Dettman, P.E.

Similar presentations


Presentation on theme: "A Technical Review of Proper Masonry Detailing Matthew A. Dettman, P.E."— Presentation transcript:

1 A Technical Review of Proper Masonry Detailing Matthew A. Dettman, P.E.

2 Overview n Water Penetration Resistance Wall Systems Wall Systems Flashing and Weep holes Flashing and Weep holes Coatings Coatings n Differential Movement Cracking Cracking Movement Joints Movement Joints

3 Problems related to water penetration n Water entry into interior n Efflorescence n Spalling n Corrosion n Reduced insulating capacity n Staining / Mold / Mildew

4 Keys to Providing Water Penetration Resistance n Quality Materials n Good Construction n Proper detailing n Maintenance

5 Keys to Providing Water Penetration Resistance n Quality Materials n Good Construction n Proper detailing n Maintenance

6 Three Basic Wall Types n Drainage Wall n Barrier Wall n Single Wythe Wall

7 Drainage Wall

8 n Water travels down back side of outer wythe, collected on flashing, and channeled to exterior through weep holes n Examples: Cavity walls Cavity walls Masonry veneer walls Masonry veneer walls Rain screen walls Rain screen walls

9 Drainage Walls Requirements n 2 to 4 ½ inch clear cavity n Flashing and weep holes to channel out excessive water

10 Rain Screen Wall n Equalizes pressure within cavity n Vents at top and bottom of wall or panel n Flashing and weep holes n Compartmentalized n Allows for ventilation and evaporation

11 Barrier Wall n Collar joint between wythes acts a barrier to moisture along with the thickness of the wall n Examples Brick and Block Composite Wall Brick and Block Composite Wall

12 Barrier Wall n Voids allow water penetration n Must be filled solid with mortar or grout

13 Single Wythe Walls

14 Single Wythe n Masonry units with coating or integral water repellent n Mortar with integral water repellent n Through-wall flashing n Weep Holes n Vents

15 Flashing Details n Locations n Placement

16 Flashing Locations n base of wall n sills n heads of windows n at shelf angles n copings n lower wall/ higher roof intersection n other discontinuities in air space

17

18

19

20

21 Good Flashing Detail

22 Poor Detail

23 Drip Edge

24

25 SS Drip Edge

26 Shelf Angles

27 Flashing Single Wythe Walls

28 Flashing with Shear Transfer

29 Flashing Reinforced Wall

30 End Dams

31 Flashing Laps

32 Drainage Materials

33 Weep Holes

34 Weep Tubes

35 Vent Weep Holes

36 Rope Wicks

37 Flashing Materials n Sheet Metal n Composites n Plastic and Rubber Compounds Compounds

38 Stainless Steel Cold-Rolled Copper Galvanized Steel Durable, non staining Durable Easy to paint and durable Hard to solder and form Damaged by excessive flexing and can stain Difficult to solder, corrodes early in acidic and salty air Material AdvantagesDisadvantages Sheet Metals

39 Lead-coated copper Copper laminates Flexible, durable, non-staining Easy to form Difficult to solder, damaged by excessive flexing, metal drip edge suggested Degrades in UV light, more easily torn than metal Material AdvantagesDisadvantages Composites

40 EPDM Rubberized asphalt PVC Flexible, easy to form, non-staining Fully adhered, separate lap adhesive not needed, self healing, flexible, easy to form and join Easy to form and join, non-staining, low cost Aesthetics if not used with a metal drip edge, full support recommended Full support required, degrades in UV light, metal drip edge required Easily damaged, full support required, metal drip edge required, questionable durability Material AdvantagesDisadvantages Plastics and Rubber Compounds

41 Bldg felt and poly sheeting

42 Colorless Coatings n Used for a variety of reasons n Recommended for Concrete Masonry n Questionable for Clay Masonry

43 Possible Dangers n Water can still penetrate n Could cause spalling n If efflorescence occurs under coating, it may be impossible to remove n Recoating will be necessary

44 Coating Types n Colorless Coatings n Paints

45 Colorless Coatings n Penetrating Silanes Silanes Siloxanes Siloxanes n Film-forming Acrylics Acrylics Stearates Stearates

46 Coating Types n Paints Cement based Cement based Latex Latex Alkyd Alkyd Oil-based Paints Oil-based Paints

47 Differential Movement n Movements Temperature Movement Temperature Movement Moisture Movement Moisture Movement Elastic Deformation Elastic Deformation n Movement Joints Design Design Placement Placement

48 Causes of Cracking n Differential Movement n Restraint n Settlement n Elastic Deformations n Creep

49 Types of Movement

50 Temperature Movement n Coefficient of Thermal Expansion Brick = 3.6 x Brick = 3.6 x Concrete Masonry = 4.3 x Concrete Masonry = 4.3 x Aluminum = 12.8 x Aluminum = 12.8 x Steel = 6.5 x Steel = 6.5 x 10 -6

51 Moisture Movement n Brick - irreversible expansion n Concrete masonry – drying shrinkage and carbonation

52 Types of Movement Joints n Expansion Joint - Brick Masonry n Control Joint - Concrete Masonry n Building Joint - Structures

53 Expansion Joint n Used in Clay Masonry n Used to separate brick into sections so cracking will not occur n Horizontal / Vertical n Entire joint is unobstructed and formed from a highly elastic, continuous material

54 Types of Expansion Joints (Details)

55 Expansion Joint

56 Typical Spacing and Locations of Expansion Joints n Long Walls n Corners n Setbacks & Offsets n Parapet walls n Beneath shelf angles

57 Expansion Joints at Corners

58 Horizontal Expansion Joint

59 False Horizontal EJ

60 Hiding Expansion Joints

61 Control Joint n Used in Concrete Masonry Relieve horizontal tensile stresses Relieve horizontal tensile stresses Reduce restraint and permit longitudinal movement Reduce restraint and permit longitudinal movement Separate dissimilar materials Separate dissimilar materials

62 Types of Control Joints n Pre-formed gasket n Formed paper n Special shape units

63 Pre-formed Gasket

64 Formed Paper (also known as Michigan Joint)

65 Special Shape Unit

66 Joint Reinforcement at CJ

67 Bond Beams n Do not cut bond beam reinforcement unless specifically indicated on the plans

68 Control Joint Locations

69 Control Joint Spacing n Two methods: Empirical Empirical based on historical performance based on historical performance Engineered Engineered based on a crack control coefficient based on a crack control coefficient

70 Empirical Control Joint Criteria n Spacing for above grade exposed concrete masonry walls Distance between joints is the lesser of: Distance between joints is the lesser of: Length to height ratio or Length to height ratio or 1 ½ 25 feet Notes: Notes: Based on horizontal reinforcement of in. 2 /ft Based on horizontal reinforcement of in. 2 /ft Applies to both Type I and Type II units Applies to both Type I and Type II units Can be modified based on local experience Can be modified based on local experience

71 Engineered Crack Control Criteria Crack Control Coefficient in./in. (mm/mm) ________________ __________ __________ ___ Maximum wall _length, ft (m)_________25 (7.62)__20 (6.10) panel dimensions_ length/height ratio_ _____2 ½ ______2___ panel dimensions_ length/height ratio_ _____2 ½ ______2___ Min. horizontal reinf. ratio A s /A n Notes: A s = cross-sectional area of steel, in 2 /ft (mm 2 /m) A n = net cross-sectional area of masonry, in 2 /ft (mm 2 /m) Criteria for Controlling Cracking in Reinforced Concrete Masonry Walls

72 Engineered Crack Control Criteria (cont.) Notes: n Need not apply if A s /A n > see Table 4. n See Table 3 for A s /A n = minimum requirement. n Minimum reinforcement ratio need not apply if length is < ½ maximum length shown in table. n CCCs less than may be available in some areas and spacing should be adjusted accordingly. n Control joint spacing may be adjusted up or down based on local experience.

73

74 Brick and Block Together n Align Expansion Joints and Control Joints

75 Bond Breaks n Use to separate bands of different masonry types

76

77


Download ppt "A Technical Review of Proper Masonry Detailing Matthew A. Dettman, P.E."

Similar presentations


Ads by Google