In the UK, there are two types of building mortars worth using, lime and cement. Generally, older houses, mainly in the pre-1920s were constructed using brick or stone with a lime mortar. Similarly, newer houses, post the 1920s use brick or stone, however, with a Portland cement mortar.
When analysing our modern building materials, it’s important to note that brick and mortar in historic buildings differ greatly from that used to build modern ones.
Firstly, modern bricks are a lot tougher than they used to be. Historically it wasn’t possible to fire up building materials to the heat that we can achieve now. In the modern day, we will typically fire bricks up to 1100ºC, this fixes the clay into a permanent ceramic form, similar to glass work.
Secondly, historic building materials aren’t necessarily designed to be waterproof, the focus was always on permeability. Permeability allows your building to be breathable and therefore absorb the water and release it without the risk of dampness or mould.
These differences need to be understood! If you use an incompatible building material during restoration then this can destroy your beautiful historic masonry structure.
Builders can now purchase fine-grain sand and Portland cement as a replacement for traditional mortar mixes. Cement-based mortar is a strong, inexpensive material that hardens quickly. In addition, due to drying times, cement mortar fits well into modern building practices. However, cement has its downfalls… It’s not breathable, it’s not flexible and it’s non-porous. The lack of flexibility with cement mortars means that during thermic expansion your building is likely to crack.
Lime mortar comes in many forms, and it’s not a one-size-fits all kind of thing. The sand and quantities used to make the mix is also important. Lime mortar, when compared to cement-based mortars, hardens much more slowly. This makes it easier to work with and minimises the chance of cracking during application. Additionally, any cracks that do form will absorb carbon dioxide and mend over time. Lime is breathable, flexible and porous. If you’re looking for an elegant finish then focus your attention toward hydrated lime. This lime is easy to work with and has a greater plasticity meaning we can get the best shape possible for your home.
Lime mortar has far superior waterproofing capabilities than cement mortar. Firstly, traditional concrete is prone to taking on moisture from the atmosphere. Once additional moisture is taken on, it is heated and cooled with the changes in temperature. All these temporary expansions and contractions in the material of traditional concrete buildings can cause structural damage if not addressed during construction.
CEMENT IN ARCHITECTURE
Compared to other building materials, concrete gives architects a lot of freedom. This allows them to come up with eye-catching designs and results, something that’s difficult when working with more restrictive materials like wood or metal. Architects can use concrete in a variety of aesthetically pleasing building projects, including infrastructure, commercial and residential construction.
WILL YOUR CEMENT STRUCTURE BE EXPOSED TO HARSH CONDITIONS?
The issue with concrete in modern architecture is that it may not maintain its flawless appearance. Due to thermal expansion, the structure will be affected by the elements. Expanding and contracting over time can have a negative impact on the building’s longevity and overall aesthetic appearance. Therefore, an architect must consider the various environmental conditions under which the concrete will be used.
Additionally, an architect should carefully supervise the pouring of the concrete so that all mixes are right and optimal workability is achieved. If the composition of the concrete is inadequate, then this increases the chances of getting pores and crevices in the structure.
The architect’s design can also help protect the structure from the elements. For example, by including eaves in his or her plans, an architect reduces humidity and prevents moisture from damaging a building’s concrete surface.
SPECIFYING ADDITIONAL CEMENT PROTECTION
Because concrete is porous, you may need to protect it from wear and tear by using an outer varnish or resin. When choosing an optimal product for protecting your cement, it is always advisable to consult with a technical expert. This is because there are many products you could choose for this purpose. Outer protection can affect the colour, brightness or tone of your cement once dried and so an expert will be able to foresee how your building may look once completed.
LIME MORTAR IN ARCHITECTURE
The use of lime mortar and plaster has been widespread in building construction for thousands of years. Though lime putty was originally used for such historic applications, most modern uses of lime involve the use of hydrated lime. Due to the exceptional water-retention capability of lime, hydrated lime is often preferred by modern day architects.
WILL YOUR LIME STRUCTURE BE EXPOSED TO HARSH CONDITIONS?
Unlike modern options, such as cement, lime allows the walls of a building to breathe. This prevents moisture from becoming trapped in the walls which can cause significant damage over time. Because lime construction helps regulate the moisture content in walls, lime can also then reduce humidity in a room. This then minimises the risk of moisture-related contaminants such as mould or condensation.
When lime is used correctly, it can last for centuries without requiring extensive repair work. Some of the oldest buildings in existence have been shown to withstand over 600 years’ worth of wear without crumbling.
Lastly, lime is flexible when met with thermal expansion. This means that lime can be used in applications where temperature fluctuations are common. High-quality lime products are often used for buildings in hot countries. This is because when subject to the occasional day of extreme cold weather, they won’t crack.
Our winner…. Lime. Lime is a popular building material because of its many benefits. It’s durable, flexible and long-lasting. This makes it an excellent choice for any type of construction project. In the long run, it will save you time and money. If you’re looking for a building material that will stand up to the test of time, lime is a great choice.
Ecoright have been working with architects, housebuilders and specialist brickwork contractors for many years, so their knowledge of lime and its uses is extensive. If you have any questions about how to use lime or its suitability to a particular project, please get in touch, they will be pleased to advise. You can read more about Lime Renders here: https://www.ecoright.co.uk/
Lime Renders are available through Ecoright’s sister companies: