Types of Brick Bonds

In this article we are examining and exploring the reasons, Cost and advantages and history of brick bonds.  This article is the first in a series of articles on brick bonds.

Most historic buildings in Capitol Hill, Dupont Circle, Georgetown, and other parts of Washington, DC are built with a limited set of masonry details.  Historic construction methods and building materials were used during the time of original construction which limited options for the style and architectural choices available for construction.   Also, at the time of original construction, highly skilled masons were prevalent in the building industries.  Today unique companies such as Infinity Design Solutions (IDS) still specialize in this type of work yet it is comparatively rare.  Between buildings designed by different architects and even years apart, many of the historic buildings of Washington DC have repeating architectural layouts, configurations, and materials.   There are many different types of brick bonds used in masonry buildings throughout the world. However, the same few brick bond patterns were commonly used throughout the historic areas of Washington DC.

The running brick bond is one of the simplest brick wall layouts.   This brick wall pattern has each brick installed above the middle of the brick below in the lower course.   Roofing and masonry don’t often have much in common but the common brick bond is built similar to a shingle layout. For functional reasons, it’s important that shingles are set so that the center of each shingle is directly above the joint between shingles below. This type of layout in roofing helps to eliminate water entry from the edges of a roof shingle. A joint between shingles is a susceptible area where water can enter and spacing that layout evenly helps eliminate water seepage and leakage.

For comparison, the simplest of all brick bonds may be the square bond.  An example follows below for reference.  This brick or masonry pattern is rarely found in the historic districts of Washington DC. You can see an article that we posted previously about these square brick bonds at the following link:  https://www.ids-dmv.com/masonry/square-bond-brick-and-block-masonry/

single-roof-layout

The picture below shows an example of a shingle roof layout. In this case, the shingle segment (in a typical 3-tab product)  itself is approximately 13″ wide.   The picture below is an example of a historic front facade mansard roof that was originally built with historic slate and has been replaced with cheap asphalt shingles instead.  Nonetheless, asphalt shingles or slate roofing, the layout is the same.  This layout is analogous to a running bond in brick masonry.

Mansard roofs were originally prolifically used in Paris, France over 400 years ago as a way to get more floor or attic space from a building and avoid counting the space towards tax assessments since it was hidden in the roof.  This is an example of how outside factors, otherwise seemingly unrelated, can affect the design and construction of buildings.

mansard-roof

The picture below shows an example of a running bond in a brick wall.  You can see each brick is set exactly halfway above the respective mortar joint below.   This layout continues throughout the entire area of construction, course after course, without change or interruption in the bond or brick layout.

running-bond-brick-wall

In comparison to brick masonry, ashlar stone masonry requires cutting of almost every stone unit.  Stones are not easy to cut and not often double wythe in thickness.  For these reasons, we see more variation in brick bonds than ashlar stone masonry bonds.

Although the running bond is one of the simplest of brick layouts, it’s not the most prolific in Washington DC historic buildings, the common bond is the most endemic.   The picture below shows an example of a common bond. The common bond typically has approximately 7+ courses of stretcher brick. However at the layout at intervals around 7+ courses, switch to a header course layout.   The photo below shows an example of a common bond brick wall layout.   The spacing of the header course can vary in this particular case there are 11 courses of running bond between the header layout. Nonetheless, this is still a common bond wall.

common-bond-brick-layout

An interesting question people might wonder about the variation in brick bonds is what’s the difference and advantages of one type of brick bond versus another.   From a structural perspective the common bond offers a higher amount of stability and strength than the running bond.   In a relatively small area of construction, the difference might be negligible. However, in large walls the difference in strength may be significant.   The alternating between a stretcher course and header course can offer strength to resist the forces of lateral deflection and brick wythe separation.   It

could be argued though that the simple running bond may be stronger from a or from a simple compressive strength analysis perspective, depending on the size of the wall assembly.  To understand the added strength derived from cross bonding and joining otherwise separate brick wythes, think about the example of laminated building materials. While individual members or elements may be weak, they can be exponentially stronger when joined or laminated together.

In the image below you can see a similar example of a common bond brick wall. In this particular picture the brick joints have been raked to clear mortar joints at the outer ¾” of an inch to 1.25″ of the face of the wall.   The mortar joint raking process is an integral step in the overall process of tuck pointing and masonry restoration. For the purposes of explanation of the common brick joint, this perfect picture shows a perfect example to to exhibit that there can be variation in the quantity of course between header rows.   To highlight the area of header courses, a set of blue lines has been applied around each header course in the picture.

brick-joints

The image below shows another wall with a common brick bond.   This wall also has a sailor course of brick indicated by the white arrow. That course is a decorative architectural element.  A soldier course of brick is similar to a sailor course, except in this case the soldier course may have provided a functional purpose, in addition to its aesthetic purposes, by creating a recess to shoulder or bear ceiling joists.

sailor-course-brick-bond

This article is part one in a series covering masonry brick bonds. Following articles will continue to explain the principles of brick bonds and brick building configurations.

From a conservation and preservation perspective, several approaches can be taken to improve conditions related to deteriorated historic brick masonry. Primarily, lime mortar brick joints and low temperature fired soft red clay bricks should be inspected and checked on a routine maintenance

schedule, either seasonally or at least annually.   If brick masonry is kept in good condition, the life of embedded wood elements can be significantly extended.  Hire a professional contractor which specializes, understands and appreciates historic construction elements and buildings.

In this article we talked about the following terminology and  concepts, follow the links below for more related information from the IDS website:

  • Running brick bond
  • Square brick bond 
  • 3-Tab roof shingles 
    • mansard roofs
    • Historic slate roof tiles 
    • Asphalt roof shingles 
    • Paris, France 
  • Tax assessments
  • Brick wythe
  • Stretcher course
  • Header course
  • Lateral deflection
  • Compressive strength
  • Laminated building materials
  • Joint raking
  • Tuck pointing
  • Sailor course
  • Soldier course
  • Ceiling joists

 

These concepts are part of the fundamentals of historic masonry restoration, tuckpointing, and brick repair.

The links in the list above will take you to other articles with more information on defects, failures, preservation and repair of historic masonry.  You can learn a lot more on our blog.  Feel free to check it out.  If you have questions about the historic masonry of your building in Washington DC, fill out the webform below and drop us a line.  We will be in touch if we can help.