Tuckpointing and repointing are two of the many terms in the masonry industry that are often used interchangeably to describe processes of brick or stone masonry restoration, especially as it pertains to historic common brick masonry and historic pressed bricks . This issue occurs in both masonry building facades and retaining walls . Although these terms refer to a process of adding new mortar joints to a brick structure, there’s much more to it than just that! Proper tuckpointing requires knowledge and skills and a detailed approach.
Continue reading to find out more about the benefits and steps in masonry restoration processes.
- Tuckpointing is the process of removing deteriorated mortar at the outer face of a brick partition. Generally tuckpointing is done at exterior walls. Understandably, the exterior walls of a building, particularly exterior facade walls, experience a much greater exposure to moisture and precipitation, temperature fluctuation and freeze-thaw cycles, and wind.
- However, in many cases interior walls also require pointing. Particularly at foundation walls at the interior of a building, often rising damp will occur which will deteriorate mortar joints faster than at a typical interior building assembly.
- This process of tuckpointing benefits the stability and longevity of a masonry wall in many ways. Tuckpointing is a process most commonly required on historic brick homes and buildings but it can be applied to almost any type of brick or stone structure where deterioration has occurred. Tuckpointing is an important requirement and prevents accelerated deterioration from continuing. Even in double or triple wythe brick walls, deterioration at the outer joints can lead to failure and or destabilization of the entire brick assembly.
The adjacent picture below shows an example of a historic brick masonry wall in Washington DC where proper tuckpointing has recently been completed.
We do not delve into the aspects and detrimental problems associated with scam pointing in this particular article, but you can see other recent articles to learn more about what scam pointing is and the damage caused by scam pointing.
- Accelerated deterioration is the process or phenomenon of building decay, failure and damage happening at an increasing rate. This process, of aging and decay, entropy of a building system is often non-linear, meaning that deterioration happens faster and faster as time goes by because as deterioration occurs, that deterioration allows or creates an increasing area for potential future forthcoming deterioration.
- Deterioration can damage buildings to the point that it is extremely expensive to repair, as damage happens at a non-linear, exponential rate. The effects of harsh weather and decay cause the openings to develop over time in the joints between masonry units. These effects are insidious and cause deterioration to accelerate as time goes by. In other words, as deterioration happens, openings in the wall increase in size and more weather, such as water and ice, is allowed to enter the brick joints and therefore those elements cause greater deterioration, at a faster and faster rate.
This leads to the entrance of water through the holes thereby leading to significant damage. Repointing is the process of sealing mortar joints that are exposed to the elements. This prevents larger repairs and further cracking by keeping precipitation, ice, wind, insects, and plants out of your building’s masonry facade.
This list of potential elements which can enter your building’s brick joints, can cause significant damage. Once damage begins to occur, once these elements have an opportunity to enter, they cause more damage and then damage happens at an increasing rate.
The following 5 elements make up the majority of the majority of major risks to a building with deteriorated mortar joints.
- Insects / rodents
- Plants and Biocolonization
The adjacent picture shows an example of a brick masonry wall which has been neglected for many decades. The wall should have been tuckpointed years ago, but with lack of care, the wall has deteriorated to a great extent.
- In the greater Washington DC metropolitan area, precipitation is a reoccurring constant issue which causes deterioration to building elements. Precipitation can occur in various forms: hail, snow, rain, and even light rains such as mist can have a consequently negative effect on building materials.
Many types of building materials, even materials that are largely water resistant, still can deteriorate from exposure to moisture and precipitation, especially when materials are saturated. Even historic bricks were kiln fired. The kiln firing process makes bricks semi-vitreous, but historic bricks were fired at a comparatively low temperature and therefore they are only semi-vitreous at best which means they are still significantly susceptible to moisture. Most damage related to water intrusion and infiltration into masonry will normally result in some visually apparent signs of deterioration such as efflorescence.
The adjacent picture shows an example of efflorescence on a brick wall at the exterior of a building.
- As precipitation enters crevices, cracks, openings, and / or textured surfaces of building materials, ice can expand with great force. This force can lead to spalling, especially in cases of improper masonry pointing. As water changes states from liquid to solid, as it freezes, ice expands in size significantly with great force. This expansion can cause materials to break, separate, and delaminate.
- As ice builds up, water can actually work upwards. Naturally, people tend to think of water as always running downwards, following the direction of gravity, but there are circumstances such as wicking (especially in the case of rising damp) and ice damming where when when temperatures fluctuate around around freezing, more or less a few degrees above or below 32ﾟF, water can build-up and actually work its way upwards into cracks and crevices behind materials that are concentrically overlapped and into building spaces that water, in a liquid state, would not normally go.
The adjacent image shows an exterior brick masonry wall where scam pointing has been done to the building. Someone actually came and applied mortar, just to the surface of the brick joints without properly raking the joints. In this case, a ledge is created on top of the brick which allows the ponding and buildup of water which in turn allows for increased infiltration and later build-up of ice in the Winter. Ice, at this location, under this circumstance, will have detrimental effects to the brick wall.
The adjacent image also shows another example where water will lay on the top of the brick where mortar has deteriorated and receded from the face of the wall due to scam pointing and overall deterioration through time and age.
- Similar to ice damming, but in circumstances even when temperatures are way above freezing, such as in the summer and spring seasons of the year, wind can also drive water deeper into building assemblies through cracks and crevices into spaces where it would not normally go. Differential air pressure, through capillary action, can pull water deep into building assemblies.
- As brick masonry joints deteriorate, cracks and crevices are created through the deterioration. Wind can then carry moisture and water or precipitation into building assemblies through those crevices.
The picture below shows an example of a brick wall where scam pointing has been done. The real problem of mortar deterioration has never been addressed properly and large holes pass deep into the brick masonry wall assembly.
Insects / Rodents
- As the mortar deteriorates, the cohesive binder dissolves through exposure to moisture and the remaining aggregate is basically not much more than just sand. Animals such as ants, termite, and other pests can borrow into masonry joints. As they borrow into masonry joints, they will create Additional channels of deterioration openings into the brick masonry building assembly.
Plants and Biocolonization
- Plants such as vines will grow and attach to soft mortar joints. The sand remaining in the mortar joints will provide an anchor point where plant roots or tendrils can extend into the more joints and cause more deterioration or accelerate deterioration.
- Mildew and other organic growth, types of biocolonization, will also grow on hydrated deteriorated mortar joints and as that plant-like growth extends into the mortar joints, it also creates an organic material layer on top of the mortar joint which allows other plants to grow, like a developing ecosystem.
The following picture shows an example of a masonry facade next to an adjacent dripping downspout. This particular downspout drips all the time in the summer because condensate water from an air conditioning system is fed through the downspout. The brick masonry at this location is constantly hydrated, the joints are so deteriorated that both the joints and the brick have become filled with mildew, moss and actual complex plant growth that the growing vegetation root system has entered deep into the mortar joints of the brick masonry.
- It’s interesting and worth noting, of all of the 5 major risks above, ultraviolet rays are not mentioned in that list. Brick masonry is one of the few building materials available which is completely or near completely resistant to the harmful effects of ultraviolet rays. Ultraviolet rays are a leading factor or force of deterioration in other building material types such as organic materials (like wood, a major building material), bitumen, polyurethane, and polycarbonate based exterior materials such as homopolymers and heteropolymers.
Read other articles on our blog and feel free to reach out to us if you have a historic property in Washington DC and would like to know our opinion on whether or not your building would benefit from pointing or masonry restoration.
In this article we talk about several types of specific risks to masonry, as mortar deteriorates, the risk of the intrusion and deterioration caused by these elements increases significantly. In the following week, we will talk more about the negative effects of these items.
Here in Washington DC, historic masonry buildings are extremely expensive and the amount of financial loss caused by improper repointing 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 following terminology and concepts, follow the links below for more related information from the IDS website:
- Binders in mortars and concrete
- Lime mortar
- Raking, of mortar joints
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.