Find out how misdirected water can cause deterioration to brick and mortar

In the past, we took a closer look at the topic of water conveyance and diversion. This topic revolves around how water is diverted and conveyed around in a way from a building properly so that rain and precipitation and the elements of nature do not harm the building unnecessarily.  Water deteriorates buildings.  Some elements and materials may claim they are water resistant but no parts of a building are truly waterproof, as all elements work together as part of an interconnected system and all systems have limitations on both duration and resistance. 

You can see a past article and post on the topic at the following link.

Water Conveyance and Facade Leakage 

The outline of topics follows, for this week’s discussion:

• Benefits of building maintenance programs 

• Water loads on buildings 

• System design factors

• Diversion pathways

• Examples of critical damage from misdirected water

• Case study: stucco delamination 

• • Scupper leak

• • Delamination
  • Concentrated deterioration of brick and mortar

I. Benefits of building maintenance programs

Every building should have a maintenance program, even if it’s a single family home, such as a historic residential rowhome here in Washington DC.   Washington DC buildings are simply very valuable, they’re expensive to buy and also require continuous upkeep and maintenance. Some of the required maintenance is seasonal and reoccurs every year, other types of maintenance recur in years and decades.  The circumstance of maintenance could be viewed from a slightly different angle, not diminishing the intrinsic use and value of the physical construct of the building itself, but theoretically, the building and property is also an investment and the upkeep and physical maintenance is directly related to the durable nature of the investment.  As a building deteriorates, the use of the facility or residence is impeded and the value of the property declines.  In economic terms, the value is deteriorated or diminished as the building ages without pragmatic upkeep.

In order to simplify the different types of upkeep needs of a building, we can break the maintenance requirements into two broad categories. The first category would be seasonal or routine maintenance and the second category would be long term system wide repair and upkeep.  Even though the two different categories are in extreme contrast, there are many anomalies and exceptions that blur the lines between them.

While maintenance programs are costly to manage and execute, the comparative cost of allowing a building to deteriorate and age, essentially wither away, without an active management or maintenance program is significantly more expensive.  It makes simple and obvious effective economic sense to manage and maintain a building with an active and proactive maintenance program.   It’s not always easy to find a good holistic thinking contractor to analyze, maintain, and repair a building but once you find a good contractor, use the relationship to protect and extend the life cycle of the various systems of the building, especially at the exterior facade.  The exterior facade and roof are essentially the hard shell of a building which protects the interior from all of the damaging elements outside in nature.

II. Water loads on buildings

Rainfall and precipitation affect buildings differently.  Using an extreme example, adobe is a type of construction, similar to masonry construction where walls are built from soils without firing of the constituent substrate materials.    In the case of masonry buildings, by comparison, the firing process essentially transforms the mortar and bricks in a high temperature kiln which makes the materials relatively resistant to the effects of water. To some extent, firing of clay bricks will convert the clay material from a permeous to semi-impervious material. Consider the process as taking a material such as mud and transform it into a semi-vitreous building material.

Adobe is used to build structures in a similar type of way but without using materials that have that resistance to precipitation and moisture. Yet, even without that resistance to moisture, adobe buildings have lasted in some cases for thousands of years due to the historically dry climates of the areas of construction. Climates are changing very fast though with extremely fast melting ice and permafrost, on Earth, and the rapid destruction of our climate, due the irreverence to climate change by mostly America and Americans for many decades.  This irreverence is driven by a particular side of the political factions and concerted disinformation campaigns which claim climate change is a hoax.  It isn’t a hoax unfortunately, we can see the effects all around us.

As climate changes, at an increasingly rapid rate, weather patterns will also fluctuate and become more extreme, into the distant future, as action (or inaction today) will take decades to stabilize and realize their full effect. We can see the differences happening before our very eyes.  The National Park Service conducted a study a few years back using LiDar to scan and analyze the effect of precipitation events of various intensities on adobe walls, built as sacrificial testing samples.  You can reference an article which reports on the findings at the following link:

Measuring the Effects of Rainstorm Intensity on Adobe Walls

In this particular instance, we are discussing the deterioration of adobe as a counterpoint or point of comparison to understand the scale and type of  deterioration of building systems from precipitation and rainfall. Even though brick buildings are made from kiln fired semi-vitreous units, they still deteriorate as a factor of their exposure to precipitation and rainfall. Historic buildings, built with historic common brick or historic pressed brick and the associated mortar joints deteriorate at a much faster rate than modern brick and mortar.  Nonetheless both historic and contemporary masonry is susceptible.  Keeping a brick building properly maintained, through periodic tuckpointing or repointing can extend the life indefinitely, but without proper upkeep and maintenance the brick mortar of buildings will deteriorate significantly.

III.  System design factors

There is significant variation in weather and the resulting effect of weather systems on buildings, depending on the geographic location and the climate associated with that location. We acknowledge and it’s important to understand that weather patterns are changing, with increasing intensity, and accordingly the effects and subsequent deterioration on buildings will also change significantly. This relationship of course, as discussed above, is not casual.  It is caused by pollution and destruction of the environment and has largely been ignored by the United States for many decades.

A secondary or correlated effect of climate change and increased or accelerated deterioration of masonry buildings, in places such as Washington DC, there is a major economic effect. Real estate in Washington DC is simply extremely expensive and very valuable. As the historic brick masonry fabric and mortar of these buildings deteriorate at an increasing rate, the financial or economic effect of related deterioration is very significant.

Precipitation is one of the most common factors in damage from excessive exposure to the elements at a masonry or brick facade.  The resultant effect is disintegration of materials in the masonry. Bricks are essentially composed of kiln fired clay which includes several different types of elements.

Historic brick mortar, on the other hand, is largely comprised of sand and hydrated lime.   Both historic lime and historic bricks have calcium but historic lime has a much greater amount of calcium in the overall composition.    When the internal areas of brick and mortar become significantly hydrated, the connection of the materials which have become bonded and chemically combined can literally dissolve and break down.   You can see deposits of efflorescence on both the interior and exterior faces of masonry because as the masonry assembly becomes hydrated, that water will naturally move from the outside to the inside but then as it dries that same water will move back out of the masonry, again.  It’s different though as the water moves back out of the masonry because this time as the masonry moves out, it has already dissolved internal materials and that water it is carrying those materials back towards the outside of the brick or masonry assembly. As the moisture makes its way to the outer face of the masonry, it then dries and goes back to the atmosphere but the calcium (salt-like) deposits are left behind in a crystalline form or structure on the surface or face of the masonry, known as efflorescence.

Sulfites and nitrates, in the absence of real and effective regulation are pumped into the environment by companies which have a clear and discernable market-driven motive to disregard or avoid better practices to clean their production by-product.  As the toxins are dumped in the environment they result in acidic rain and many other extremely negative environmental consequences.  These toxins change the chemical makeup of rain and precipitation and eat through masonry over time as deterioration is significantly accelerated. 

The discussion continues into factors and diversion pathways which lead water away from buildings.  There are both passive and active types of systems to convey water away from buildings and divert water away from critical areas such as facades and foundations.

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:

• #57 Stone

• aggregate / sand

• Asphalt

• Acoustical Sealants

• Aggregate or crushed stone

• Art deco style architecture

• Asphalt paving

• Attic or roof crawlspace

• Bat closers

• Beaux Arts Architecture, Second Empire

• Best Practice – Avoid exposed fasteners in a horizontal plane of a low slope roof

• Better Business Bureau (BBB)

• Binders in mortars and concrete

• Biocolonization of stone and masonry

• Block and Tackle, hoisting

• Bollards and Ram Raid Protection

• Boom lift

• Bracing and shoring systems, temporary

• Brick bat or closer bricks

• Brick burns 

• Brick kilns

• Brick opening infilling

• Brick wythe

• Broom finish, concrete

• Brownstone

• Building Code 

• Building facades

• Bull’s-eye window

• Butter joint

• Capillary action

• Carved ornate sandstone

• Cantilever

• Cast iron

• Cementitious siding

• Cheek wall, masonry — Draft

• Chemical testing

• Classical orders, Doric, Ionic, Corinthian

• Cobblestone paving

• Code, building — Draft

• Cold joint

• Cold weather masonry work — Draft

• Commercial roofs, flat roofs

• Common bond brickwork

• Common brick, historic

• Copper sheet metal

• Classical orders

• Cobblestone paving 

• • Common bond 

• Concrete sidewalk

• Corbel

• Cornice, metal

• Corten steel

• Curtain wall

• Damp proof course

• Delaminated building materials 

• Dome strainer

• Downspout

• Drip edges

• Drip trails

• Efflorescence 

• Egg and Dart

• Exposed aggregate concrete 

• Electrical distribution panel — Draft

• Electrogalvanization, zinc

• English bond brickwork

• Escutcheon, architectural

• Expansion joints and building movement joints

• Expansion joints in concrete and masonry flatwork

• Exposed aggregate concrete

• Exterior Insulated Finishing System

• Fenestration

• Ferrous metals

• Fire escape stairways

• Flashings and Counterflashings

• Flatwork, concrete

• Floor flange

• Freize, architectural

• Gantry cranes

• Glass curtain wall

• Granite stone

• Gravel

• Great Chicago Fire

• Green bricks 

• Green roofs

• Green walls

• Gutter, roof

• Header failure

• Hip roof

• • Historic common brick 

• Hollow (modern) brick, aka perforated brick

• Homopolymers and heteropolymers

• Ice damming

• Infill, brick

• Iron oxide

• Kentledge

• Kiln firing of bricks

• Leak trails (See drip trails)

• Lime mortar

• Lintel

• Load path

• Modified bitumen, roofing

• Moisture Meter

• • Mold 

• Mildew

• Multimeter

• Oriel window

• Oxidation

• Parallel invention

• Parapet coping

• Parapet Walls

• Penetration (building assembly)

• Pigeonhole brick wall corners

• Plank Ladder Scaffolds

• Plug, clay

• Pressed bricks

• Quarry tile

• Quoining

• Raking, of mortar joints

• Raggle, aka reglet

• Rendering, cement

• Rebar, aka concrete reinforcement Rebar

• Rear ell, aka. dogleg

• Rectilinear

• Retaining wall 

• Ribbed mat concrete footing, foundation type

• Rising damp 

• Roman bricks

• Roman arches

• Roof eave

• Roof scuppers and conductor heads

• Roof termination 

• Row buildings and row homes

• • Rubbed bricks
  • Rubble stone masonry 
  • Sand, Builder’s 

• Second Empire

• Sedimentary rock

• Scam pointing 

• Scaffolding

• Scratch coat

• Spalling

• Spark arrestor

• Sprung arch

• • Squint bricks, 

• Stone masonry

• Strike, or striking of mortar

• Tapestry bricks

• Tooth-in, interlocking masonry connections

• Tuck pointing, aka point-up, repointing

• Vitreous

• Water and leak trails

• 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.