The age of your building is the first indication of the type of mortar used in its construction. Most houses built before the 1900s were constructed with lime or earthen mortars. These materials are much more durable than modern Portland cement, which was not introduced until the mid-19th century. As a result, buildings constructed with lime or earthen mortars are typically in better condition than those built with Portland cement.
It wasn’t until the mid-1900s that lime mortar was replaced by Portland cement. This was firstly achieved by adding natural cement to hot mixed mortars, which resulted in a quicker set. However, this still required more skill and time than Portland cement. By the 1950s, Portland cement had been adopted in nearly all construction projects, with very little lime being used. This was due to the many benefits it had over lime mortar at the time, such as its resistance to weathering, ability to be mass-produced, faster setting times and low cost. As a result, Portland cement became the standard for construction projects worldwide.
Portland cement is a binding agent used to create concrete, one of the world’s most widely used construction materials. Although it was first developed in the 18th century, it did not gain widespread popularity until the late 19th century. The primary reason for its popularity was its affordability; cement could be produced at a fraction of the cost of other construction materials. In addition, it is set a lot faster, and the cement is extremely strong and durable, making it ideal for use in modern buildings. Today, cement is still one of the most popular construction materials available, and its use shows no sign of slowing down any time soon.
Cement Mortar In The 20th Century
The early 20th century saw a boom in the construction industry. New buildings were going up everywhere, and cement was one of the most popular materials used to construct them. Cement is affordable, strong, and durable, making it ideal for commercial and residential construction. In addition, cement can be moulded into any shape, making it perfect for various applications. As a result of its many benefits, cement became one of the most popular construction materials of the early 20th century.
Cement is usually a grey powder but can also be purchased as a white powder; mixing it with different sands can give off different colours when set, like greys, yellows and even whites. The tell-tale sign for cement mortar is a smooth finish. Soft building sand is typically used for cement mortar. This can be used because it shrinks a lot less than lime mortar. However, some traditional houses have been built with river sand mixed with natural cement and quicklime to make a mortar. These buildings are typically aged around the 1930s-1950s and are usually brick.
Adverse Effects Of Cement Mortar
Cement mortar is commonly used in the construction and repair of traditional buildings. However, this modern material can have detrimental effects on the breathability of walls, leading to damp problems and an increased risk of mould growth. In addition, cement mortar is much harder than traditional lime mortars, which can cause erosion of soft masonry over time. Finally, cement mortar is nonporous, not allowing water vapour to escape. This can lead to condensation and further damp issues. As a result, it is vital to consider the breathability of a building before using cement mortar in its construction or repair.
The negative environmental impacts of cement production are well-documented. Cement production is responsible for significant greenhouse gas emissions, and cement is a major contributor to air pollution. Cement is a non-renewable resource, meaning its use results in the permanent loss of this valuable material. As cement production continues to increase, the negative environmental impacts of this industry are likely to become more severe. To protect our environment, we must find alternative construction materials. Thankfully, several promising alternatives to cement are being developed, and it is hoped that these materials will eventually replace cement as the standard building material. In the meantime, we must reduce our reliance on this environmentally harmful material.
Traditional building materials such as wood, earth, lime and stone are much more environmentally friendly, and they can also be reused or recycled when they are no longer needed. Using these sustainable materials can help reduce the negative impact of cement on the environment.
Lime Mortar
In the days before Portland cement, lime was the primary binding agent used in mortar. To make lime mortar, (calcium oxide) was mixed with water to form a paste, which was combined with sand and other aggregates to create a mortar. It has been used for centuries in construction, and its popularity is due to its versatility and durability. One of the reasons why lime mortar is so durable is that it can harden both under wet and dry conditions. It can be used in many environments, from damp caves to sunny desert cities. In addition, hot lime mortar is highly resistant to damage from freezing and thawing, making it an ideal choice for areas with a harsh climate. As a result, it is no surprise that lime mortar has been used in some of the world’s most iconic buildings, including the Great Pyramids and the Colosseum.
A lime mortar is a type of mortar that is made by mixing lime and aggregate. Lime mortars were used extensively in the past, but today they are mainly used for restoration work. Historic lime mortars usually have visible white lumps of unslaked lime, as well as other visible aggregates like bits of coal, brick, pebble or shell visible. This is because locally sourced materials were used in the past; river sand or pit sand was the most common aggregate used historically, mainly due to its locality; for gauged brickwork, limestone was slaked down to a powder often mixed with chalk or fuel ash. Today, however, a wide variety of aggregates can be used in lime mortar, giving it a wide range of colours and textures. Different aggregates can also create interesting visual effects, like including bits of colour or sparkle in the mortar mix.
Traditional Repairs With Lime Mortars
Any repair work should be sympathetic to the original construction. This means using the same materials wherever possible. Cement-based mortars were not used in traditional buildings, so any repairs using these should be avoided. The best way to find out what sort of mortar was used in the original construction is to take a sample from a hidden area and analyse it. However, if this is not possible, you can usually tell the difference between cement and lime mortar by doing a simple test.
Cement typically stays quite hard, even when wet, whereas lime mortar can be easily raked away with a sharp tool or nail. You can also drop a sample in vinegar to see if it fizzes; however, this may not be accurate if the model is a mixture of lime and cement mortar. Once you have identified the type of mortar, you can match it as closely as possible when doing repairs. Using the wrong type of mortar can cause severe damage to a historic wall, so it is essential to get it right.
Hot lime mortar can be used for various applications, including pointing, rendering, plastering, torching and floor screeding. It is also suitable for other repair work, as it can bond well with old and new masonry. One of the most distinctive features of lime mortar is its colour. While most mortars you see are grey or white, lime mortar can vary quite a lot in colour depending on the local materials used. The most common colours of lime mortars in Yorkshire are shades of white, black, red and yellow.
Hydraulic Lime Mortars
Hydraulic lime (NHL) is a type of lime resistant to water. It was first used in the construction of the Eddystone lighthouse and has since been used in various projects, including the restoration of historic buildings. While NHL has many benefits, its low permeability has caused concern among conservationists. Data collected from multiple sources show that NHL mortars have experienced significant increases in strength, with very low permeability, which can lead to further damage if not adequately monitored. As a result, conservationists are developing new methods for monitoring NHL-treated buildings to ensure long-term preservation.
The origin of pozzolans as a binding material can be traced back to the early days of concrete and mortar production. The Roman Empire made extensive use of this type of material in their construction projects. Pozzolans are finely ground particles or ashes that consist of wood ash, brick dust, fuel ash and volcanic materials like trass. When added to a hot mixed lime mortar, they give it a hydraulic set, which helps to increase the life of your mortar. However, it should be noted that adding too much pozzolan can lower the permeability of your mortar, so care must be taken when measuring the amount added. Overall, using pozzolans is a tried and true method for improving the quality and longevity of concrete and mortar products.
Benefits of Lime Mortar
The microstructure of hot lime mortars is responsible for their compatibility with traditional masonry. Mass masonry construction relies on moisture being able to move through the mortar freely to prevent damage from weathering. Microporous pathways interconnect the voids in the mortar within the binder, which allows the mortar to transmit fluid. This makes lime mortar ideal for use in areas exposed to severe weather conditions, as it prevents moisture from being trapped inside the masonry. In addition, the porosity of lime mortar also allows it to breathe, which helps to regulate the internal temperature of masonry walls and prevents condensation from forming. As a result, lime mortar is an essential material for use in traditional masonry construction.
In the historic environment, lime mortar is recognised as the best-performing construction material to use in repairing and conservating traditional buildings. Its benefits over modern cement-based mortars are widely accepted, yet its use is often feared because it is complicated to mix, apply and cure. However, with the proper training and a little practice, anyone can learn how to use lime mortar successfully. The key benefits of lime mortar include its breathability, which helps to regulate moisture levels within buildings and prevents rising damp; its flexibility, which allows it to move with the building as it settles; and its strength, which increases slowly over time as the mortar sets and hardens.
