Everything you need to know about front lumpers and pressed bricks
It’s interesting that pressed brick is so prolific at front facades, as we think a little about the distinction between pressed brick and common brick. In a recent blog we talked about the differences in manufacturing and the effect of the process which led to a much higher cost for pressed brick. We also looked at the division of labor between front lumpers and skilled laborers. As a recap, the general contractor, in historic times, would build the majority of the building’s brick structure, namely the rear and side walls and interior wyther of the front facade, in many cases, but the front layer of brick in the double wythe or sometimes triple wythe front wall, would be built with pressed brick. The pressed brick has a much finer and thinner mortar joint and greater overall consistency between individual brick units. These thinner joints, known as butter joints, are built with a higher ratio of lime and therefore have a comparatively higher compressive strength and higher resistance to permeability.
What Is A Brick Wythe
A brick wythe is a single layer of vertical brick in a masonry assembly. It’s rare, but in some cases such as small or thin yard screen walls, a sole single wythe construction can be used. In Washington, DC, it’s more common, in historic row homes for the above grade walls to be built with a double wythe brick assembly. Larger warehouse and commercial walls will often be built with a triple wythe construction and brick foundations will also often be built with a triple wythe brick assembly. It’s also common to find historic buildings built with a stone foundation. Granite stone was commonly used for foundation construction in Washington DC. In most cases these stone foundation walls were built with a rubble style assembly as opposed to an ashlar style stone masonry construction.
In many cases, with painted rowhomes, the finer butter joints at press brick walls are muted or somewhat disguised with paint, in the many decades that facade painting proceeded the original construction. Paint on the front facades of buildings makes the fine masonry work almost disappear and blend in, disguised, in a more monolithic singular aesthetic.
How Historic Pressed Brick Looks Like
The picture below shows an example of a historic pressed brick front facade wall at the inside corner of the area above the front entrance bay. The entrance is recessed back away from the front bay and the front bay in the living room sticks out beyond the wall at the entrance. This type of layout is found in Italianate or Victorian style rowhomes without a Mansard style front porch. The wall at this rowhome front facade was painted with a light gray color paint and you can still see the recesses in the mortar joints, despite the layers of paint. These recesses should have been pointed and addressed before painting, but years ago when it was last painted they just painted directly over top of the deteriorated mortar joints which is not best practice. When working with painters, make sure they understand the principles of historic masonry and historic rowhomes in Washington DC. In many cases it’s best to talk to a brick restoration or pointing specialist before working with a painter. Some companies such as IDS actually do both masonry restoration and painting of historic masonry.
Mortar Joints and Downspouts Leakage
In the picture below you can see the fresh wet lime mortar directly after installation or application. Lime mortar will dry to a much lighter color. The joints at this particular area of the wall had experienced accelerated deterioration because of a leaking downspout from the gutter above. This particular building had a mansard roof at the front facade. That mansard roof started at a built-in gutter similar to a traditional water table, but in this case the gutter was intended to divert and funnel water to the small downspout. That particular original downspout was made with a ferrous metal alloy and had oxidized over time. Small downspouts will often become clogged with tree debris such as leaves, bark, and acorns or other tree seeds. Clogs in gutters will accelerate oxidation amd deterioration.
As the years went by and the downspout continued to leak, water was shed or spilled across this area of the wall and those mortar joints, at the brick at that area of the front wall, deteriorated faster than they would have otherwise. Eventually, the deteriorating mortar joints, with a concentration of water being applied to this area of the wall at each precipitation event, led to water ingressing from the exterior through the motor joints, into the interior plaster. It was at that point when the client reached out and hired us to repair the exterior brick and interior plaster, but the problem could have been fixed earlier, at the source before damage had spread to the interior of the building.
For comparison, the picture below shows the common joint at the rear exterior facade of a wall at a similar DC rowhome. These mortar joints are much wider and the overall ratio of brick and mortar includes much more mortar. Common mortar was comparatively much cheaper than the brick itself, in a volumetric basis. Much of the constituent substrate materials in mortar were sourced even more locally than the brick itself.
The next picture below is a close up of the same wall and you can see that both the mortar and the brick itself were rougher and less consistent than the pressed brick wall assemblies. Signs indicate though that this wall was not built at the same time as the rest of the house. The main part of the house, in this example was built in the early 20th century. That age is consistent with most of the historic row homes in Capitol Hill west of East 14th street, for example. However, common in this particular example there are several signs that indicate the brick and mortar may be slightly newer than the rest of the home, one of the main differences is that the mortar in this example does not show chunks of less than completely pulverized slaked lime.
Pressed Brick Front Facade Examples
The lower portion of the wall in the picture below had been pointed in previous decades. You can see the quality of the masonry work is very low and they did a very poor Job of applying the mortar. You can see that the new mortar used in the repointing process was haphazardly applied and slapped onto the exposed face of the brickwork.
In the wapl area just above the repointed area, there is a stairstep crack, likely related to differential settlement at the base of the rear facade of the building. Our company was hired to restore the masonry at the stairstep crack and in the picture below we’ve highlighted that area in blue.
Stairstep cracks are structural defects related to settlement of the foundation or underlying load path and bearing.
The next picture below shows another example of a pressed brick front facade. Unlike many of the others, this particular facade has not been painted. The brick was pointed in years past, but unlike the original mortar, this is an uncolored mortar. At the time of original construction many of the mortars were dyed by using brick dust or other color pigments to give a decorative effect to the mortar itself.
Sewer Brick Examples
The picture below shows an example of a sewer brick, used as a walkway paver. DDOT commonly uses sewer brick because it is a solid structural fired clay brick that can be installed without integral or applied spacers and no martar joints. Sewer bricks can also be used in structural wall assemblies as well, so it is a versatile brick, and cost effective. This installation shows an example of brickwork without mortar joints, for comparison to the thin butter joints of pressed brick.
Common Brick Examples
The picture below shows another example of common brick laid with a ½” to ⅝” mortar joint. This example is a stark contrast to the fine and precise work used in pressed brick wall assemblies. This particular wall happens to be built with a common bond. Common bonds sound similar to common brick but any type of brick can be used for a common bond assembly. The common bond applies to the layout or configuration of the brick and not the type of brick itself. This particular type of assembly has five courses of stretcher bond brick between each course of header brick. Common bonds can alternate in one building to the next with more or less than 5 courses of uninterrupted stretcher joint courses.
How To Maintain, Repair And Care Historic Buildings
To properly maintain, repair, and care for these historic buildings, a knowledge, interest and understanding of historic building principles is required. Here in Washington DC, historic masonry buildings are extremely expensive and the amount of financial loss caused by improper repointing and low quality construction is staggering. However, in addition to the direct financial value of the property, there is also a cultural loss when historic buildings are damaged. By comparison, consider neighboring poor cities, when historic buildings are damaged, it’s not just the loss of value to the property owner, there’s also a loss to all inhabitants and visitors of a city, present and future, who care about architecture, history, and culture.
We encourage all of our clients, and all readers of this article and to our blog in general, to prioritize the historic built environment of Washington DC and neighborhoods such as Capitol Hill, Dupont Circle, and Georgetown and become educated on on the difference between proper historic preservation versus improper work which leads to significant damage to the historic fabric of a building.
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 terminology and concepts of historic masonry restoration, follow the links below for more related information from the IDS website:
- Binders in mortars and concrete
- Brick burns
- Butter joint
- Capillary action
- Cantilever
- Cementitious siding
- Cheek wall, masonry — Draft
- Chemical testing
- Code, building — Draft
- Cold joint
- Cold weather masonry work — Draft
- Damp proof course
- Downspout
- Electrical distribution panel — Draft
- Fenestration
- Ferrous metals
- Great Chicago Fire
- Green bricks
- Gutter, roof
- Lime mortar
- Lintel
- Load path
- Oriel window
- Oxidation
- Parapet coping
- Plug, clay
- Pressed bricks
- Raking, of mortar joints
- Raggle, aka reglet
- Rectilinear
- Roman bricks
- Roman arches
- Roof eave
- Roof termination
- Row buildings and row homes
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- Rubbed bricks
- Rubble stone masonry
- Sand, Builder’s
- Sedimentary rock
- Scratch coat
- Sprung arch
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- Squint bricks,
- Strike, or striking of mortar
- Tapestry bricks
- Tooth-in, interlocking masonry connections
- Vitreous
- Water diversion systems
- Zipper-joint
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.
