Avoiding Cracks in Stack Bond Brampton ON

I have heard that masonry laid in stack bond is more likely to crack than masonry laid in running bond. Why? Assuming walls were built using the same mortar and brick in Brampton, why wouldn't the vertical joints in stack bond be as strong as the horizontal joints in both stack bond and running bond?

Ian Johnson Inc
(905) 450-3260
8 Nelson St W #514
Brampton, ON
 
Reinders + Rieder Ltd.
(905) 457-1618
57 Mill Street North, Ste. 201
Brampton, ON
 
Reinders Consultanta Ltd
(905) 457-1618
201 County Court Blvd #500
Brampton, ON
 
A & R Plaster Design
(905) 799-5723
29 Strathearn Ave #8
Brampton, ON
 
Matthews Design & Drafting Services
(905) 873-7713
60 Dayfoot Dr
Georgetown, ON
 
Gerald P Belanger Arch Inc
(905) 451-8015
20 Novella Pl
Brampton, ON
 
Artistic Finishes
(905) 495-7659
45 Regan Rd
Brampton, ON
 
Onter Construction Inc
(905) 793-2344
21 Kenview Blvd #11
Brampton, ON
 
Reinders & Rieder Ltd
(905) 457-1618
Unit 201 57 Mill St N
Brampton, ON
 
Connolly Eric
(905) 877-0739
16 Main Street South
Georgetown, ON
 

Avoiding Cracks in Stack Bond

Provided By:

Source: MASONRY CONSTRUCTION MAGAZINE
Publication date: August 1, 1994

I have heard that masonry laid in stack bond is more likely to crack than masonry laid in running bond. Why? Assuming walls were built using the same mortar and brick, why wouldn't the vertical joints in stack bond be as strong as the horizontal joints in both stack bond and running bond?

Unreinforced stack bond walls are more likely to crack vertically than walls built with running bond. That is why ACI 530 requires any masonry laid in other than running bond to have horizontal joint reinforcement spaced no further than 4 feet apart in order to control cracking.In a running bond wall, any vertical crack must either pass through a brick at every other course or follow the mortar through head and bed joints. Usually the weakest path is through the units. Therefore the wall's strength is determined mainly by the strength of the units, not the mortar bond strength at head joints. In stack bond walls that are not reinforced, resistance to vertical cracking depends solely on mortar-to-brick bond, which is weaker in vertical joints than in horizontal joints. Better bond is developed in horizontal joints because the weight of the masonry keeps the joints under pressure throughout construction. If cracks do develop, they generally are very small because of this compression.

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