Everything you need to know about how rain affects a brick building facade
In the early autumn season of the year 2022, there have been several heavy rainstorms which have caused leaks and buildings throughout Washington DC. Our company, IDS, has worked both on the roofing and facade repairs and in the interior repairs of those building defects and the damage caused by water entry into the building interiors.
The image below shows a view of above a historic brick facade in Capitol Hill. The built-in gutter was restored after this picture was taken, but in this state, this picture shows the deteriorated internal gutter which is graded improperly at certain locations. As a result, rain water entered from the brick mortar joints into the interior assembly space and all the way to the internal l plaster walls. As the plaster deteriorated, the internal mortar joints also deteriorated at an accelerated rate.
For the sake of simplicity, a building facade could be simply defined as a building exterior. Our IDS company website includes dozens of thorough articles about historic masonry facade preservation and restoration. But, not all building facades are made with historic brick masonry. Wood, glass, concrete, aluminum, even vinyl materials are alternative materials used in building facades. Sometimes, several different materials can be mixed together and in concert to create a building facade.
Water affects each of those material types differently, Even within each particular material class, there are several different types of facade configurations and details to how a facade can be built. Each different type of facade design can have different levels of resistance to moisture and rain. Some of the characteristics used to compare the value of these building materials follow:
- Total cost (= substrate harvest cost + manufacturing cost + transport cost + installation coefficient + lifecycle costs)
- Longevity
- Mass and implications on building frame.
- Fire resistance
- Aesthetic value
- UV and pest resistance
The picture below shows an example of a brick building, built approximately 100+years ago in Georgetown along the canal. Four distinct areas are marked on the photo to show areas where water is being directed from the roof and top of the facade down further to the brick masonry below. This is historic brickwork, with historic mortar joints, is more susceptible to water entry and associated deterioration than modern mortar joints.
The picture above shows an example of the types of costs (and values) related to building facade lifecycle maintenance. (eg: Total cost in terms of financial outlay, building longevity, mass and structural implications, fire resistance, aesthetic value, and UV and pest resistance.)
All of these different types of costs have a significant environmental impact as well. Historically, people looked at cost without considering the environmental impact, even recently in modern politics, the impact of destruction of the natural environment and overconsumption of energy resources Is highly debated. One side of the political spectrum believes there is nearly no effect to destroying the environment and overconsumption of resources while the other side believes that it could literally lead to the extinction of much of the life on Earth. We should take these concerns very seriously because the side which believes in science and the risk to the environment is correct, our world is literally at grave risk. Environmental impacts are not listed in the list of 6 factors above because all 6 of those factors are intertwined and interconnected with environmental impact.
Cost
We listed out 5 different parts of cost.
- The substrate cost is the harvesting cost of the raw materials. Most of the raw materials in building construction are derived from natural resources from the Earth. Mining or extraction is required to get those materials out of the Earth, in most cases. Then in some cases there’s other processes required. One of the major subcomponents of brick, modern and historic alike is clay (largely constituted by silica and iron). These materials are mined directly from the Earth but still have to be processed after excavation. Modern bricks are still heterogeneous in composition, the raw elements come in a variety of shapes and forms, But the substrate materials of modern bricks are filtered to create a composition much more similar to a homogeneous mixture. This filtering and sifting is costly, both in terms of labor and in terms of machinery usage / depreciation and in terms of consumption of energy resources.
Longevity
- Whether apparent on the surface or not, the longevity of the building materials are directly related to the cost. For example, by using an extreme comparison, if one type of material costs 10 times as much but lasts 10 times as long, you could argue that the value of those materials are actually similar. Even though one material is 1/10 of the cost, it only lasts 1/10 of the time so therefore, in the whole lifespan it would have to be replaced 10 times. Therefore, it would actually cost 10 times as much and the two different materials would have a near equivalent overall cost-benefit. In a very simplified example scenario this all kind of makes sense. But in the real world there are many other factors that play into this analysis. In property and construction cost analysis, there is a time-value of money. Another consideration is inflation. Inflation diminishes the value of an investment over time.
Mass
- The consideration of mass is relatively straightforward. Simpler than some of the other analysis methods related to cost and longevity. Some building facades perform very well, but in some cases they are also very heavy. Extremely heavy building facade materials require that the superstructure of the building is built to a higher capacity to support the weight of the facade material.
- Brick and concrete materials are examples of heavy building materials. As an extreme counterpoint, vinyl siding, by comparison, is extremely light weight. It barely weighs more than cardboard.
- Building facades can be constructed in 1 of 2 primary ways. One method for construction of the building facade is for the facade itself to constitute a major or entire part of the load path, as is the case with traditional Washington, DC historic brick row buildings. By creating a building facade that comprises the entirety of the load path, in effect that the building facade itself, the facade does notneed to be separately supported. On the other hand though, by comparison If a building facade does not constitute the structural load path of the building, it requires a more robust superstructure to support the greater mass of that facade.
- The picture below shows an example of a mansard roof building, built as a standalone construction, apart from a row. In other words there are no connecting buildings. The side, front and rear walls of this building constitute the entire principle Load path of the building. If all interior partitions and walls bear on floor members which transfer the load to the brick masonry structural exterior walls, those exterior walls themselves are the principal structural load path.
Fire resistance
- Creating historic brick masonry was extremely tedious. The installation itself was extremely laborious as well but if you look just at the process of brick manufacturing as detailed in last week’s blog article on our website at the following link, you can see examples of specific steps in the process of creating bricks and why it was extremely costly from a labor perspective. Although it was expensive, brick had several advantages to other materials, ubiquitous and prevalent at historic times (and even today) in America (and throughout the vast majority of the world). Advantages span from durability, longevity, strength and fire resistance. For example, by comparison wood is highly susceptible to moisture and although cheap and lightweight, it also is highly susceptible to fire. In fact wood or timber construction buildings, once set to fire by accident, lightning or any other method would ignite quickly and burn hot and fast. By comparison though even in historic times, we recognized that bricks did not combust. A settlement, town or even a block of homes built out of historic brick would be comparatively resistant to fire. Each individual home can still burn, but the typical spread of fire that engulfs and then jumps from one building to another and another as is common in stick framed wood buildings, simply in the same incendiary rapid way fire would spread beyond control destroying large cities in America. The modern building codes all stemmed out of and as a result of devastatingly disastrous fires in American cities. One of the lasting effects is the prevalence of historic brick rowhomes in our cities which remain today.
Aesthetic
- Everyone can have a different opinion about what they think is aesthetically beautiful, but it’s clear that brick is regarded as a sign of some degree of wealth. In historic times brick buildings were more expensive, as they are today and although there is an entire spectrum of the cost and artisanship required in the different styles and types of brick construction, it’s evident that brick buildings are regarded as more architecturally significant, built with a greater investment. Often, we will see brick buildings that have accompanying architectural details of great beauty. Overall, masonry buildings are considered one of the most beautiful types of architectural construction.
The image below shows several different buildings, at the upper areas of the facade, in need of restoration. These buildings are particularly beautiful buildings, even in the current state of disrepair, built with great quality, and painstaking detail applied to the architectural characteristics.
UV
- Ultraviolet radiation is very similar to rays of light that come from the sun or other sources. In fact, on the spectrum of radiation, ultraviolet and visible light are very close to each other. Exposure to ultraviolet radiation can cause advanced deterioration to many building materials. UV degradation affects many natural carbon based materials, synthetic polymers including TPO/ bitumens, asphaltics, neoprene, polyvinyl chloride (PVC), and many others. The fiber surface of wood building materials will gray, check, shrink and deteriorate with exposure to ultraviolet rays.
- Brick, stone, and glass though, by comparison, are almost completely unaffected by exposure to ultraviolet. They can last for centuries without observable deterioration as a result of exposure to ultraviolet rays.
- We took a look at several brick masonry facades following a recent rainstorm. You can learn a lot by literally getting out in the middle of a rainstorm yourself and watching how rain and water runs down a building facade. Often in leak searching, we will use a simple garden hose to apply water to the facade of a building. Sometimes that process can be effective, but whenever applying water through a hose, it’s never as thorough and extensive as the amount of water that can be simply applied through regular natural rains.
Some reasoning and explanation follows: The typical moderately heavy rainstorm may drop over 1 inch of water per hour. Even in the case of a roof of just 1,200 ft², that’s over, 1,200 CF of water in a 12 hour period. That is equivalent to almost 9,000 gallons a water. Water applied through a hose is no volumetric comparison, it would take longer to get 9,000 of water through most garden hoses and the application would not be dispersed in the same wide-range of areas over a building.
Looking at various brick buildings, you can see that a few elements are somewhat typical even between different designs. Throughout the many decades of historic brick construction in urban areas such as Washington DC, Capitol Hill, Georgetown and Dupont Circle, you can see that there are trends that were repeated in the layout and design elements at exterior façades. These details are not just to improve the aesthetic quality of a building, many are also part of the building’s water shedding characteristics.
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
- 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
- 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.
