When it comes to repairing and restoring heritage buildings, there are few things more challenging than dealing with damaged or decayed brickwork. Not only is it a complex process that requires a great deal of knowledge and skill, but there are also safety concerns that must be considered. If damaged brickwork is left unchecked, it can compromise the structural integrity of the entire building, putting both the building and its occupants at risk.

When it reaches the point that heritage brickwork has to be replaced, it is not a job for a general bricklayer who uses conventional building methods. At best, the restoration would look unsightly and at worst it could cause much greater and more permanent damage.

In order to fully grasp the reasons behind the changes in the modern building industry, it is important to delve deeper into the skills and materials used today and compare them to those of the past. The techniques used for application and mixing also play a vital role in this transformation. While the conservation of a building’s fabric and character may have been a top priority in the past, it is not always given the same level of emphasis in modern times. 

By exploring these key factors, we can gain valuable insights into the evolution of the building industry and its impact on our communities.

The Responsibility To Preserve History

If you own a listed building, you have a responsibility and play a vital role in preserving the character of that building, which can vary based on the particular listing criteria.

In practice, this typically means that repairs and alterations that affect a protected aspect of the home are likely to be subject to listed building consent to ensure any work undertaken is sympathetic to the original building and looks like it could have always been there.

This is even more so the case for restorations and repairs of protected characters, which need to be undertaken by skilled heritage workers using traditional techniques appropriate to the materials the building originally used.

The Importance Of Matching The Original Bricks

Enlisting the services of a qualified and experienced conservation firm is paramount, because you need to ensure that the original brickwork is matched throughout the project. This is important from an aesthetic point of view, of course, but also because the brickwork’s porosity is also a key factor to take into consideration. The work must be carried out in such a way as to not disturb the functionality of the masonry and mortar around the repairs. 

When cutting out the affected bricks, it’s vital that new damage isn’t caused to the surrounding area and only those bricks that have sustained damage or decay should be replaced. As such, it is necessary to carry out a robust survey of the wall in question before work is carried out.

When sourcing appropriate bricks for the repairs, always make sure that your choice of replacements match the size, shape, texture, colour and type of the original bricks. And double check that the durability of your bricks is appropriate, as using the wrong type of hard brick can actually accelerate decay.

Lime Mortar Vs Cement

One of the biggest examples of this and a prime case of where a modern unsympathetic repair can outright destroy a building is when cement is used to repair an old building.

During the late Victorian era, the availability of cement revolutionised the building industry. With the need for rapid construction and loss of skilled labour during the war, cement became the favoured choice. Its rapid setting time meant that buildings could be produced at a much faster rate than before. This not only allowed builders to construct quickly but also at a lower cost. 

The use of cement requires less skill, which helped to increase the number of workers in the industry. It is also very easy to mix using just water and a mixer, easy to apply and thanks to industrial manufacturing methods relatively cheap.

By contrast, the vast majority of brick and stonework prior to the late 19th century used lime mortar, which was softer and more sympathetic to the more natural materials used.

Historically, to make lime mortar quicklime was slaked with water and mixed together with grit sands to make a hot workable mortar that could be used for building, plastering and pointing. Making a hot mixed mortar took time and required the knowledge of how to slake the lime properly.  

Because lime cures by carbonation it draws in carbon from the atmosphere and exchanges this with the water molecules trapped within the masonry, It takes time to harden and this gives some flexibility, helping to prevent damage to the brickwork as it settles.

Whilst this inherently made it softer than cement mortar it still proves to be a durable material and the stone and brickwork itself will be largely unscathed by the years.

Why Can Cement Destroy Old Brickwork?

When it comes to repairing a porous masonry wall, many people opt for cement mortar. After all, it’s known for its strength and durability. However, what may seem like a logical solution can actually make the problem even worse. It turns out that cement mortar can actually weaken the wall by trapping moisture behind it. 

This puts additional stress on the stones and bricks and causes them to absorb more water, ultimately leading to erosion and the eventual collapse of the wall. It may seem like an ironic twist, but it’s an important lesson to learn for those looking to keep their masonry walls intact for years to come.

When it comes to preserving the integrity of an older building, a heritage brick worker knows that every detail matters. That’s why they take extra care to use proper methods and materials when repairing or restoring historical structures. One of the most important considerations is the type of mortar used. 

Instead of opting for the easy solution of cement mortar, which can cause damage to the brickwork over time, a heritage brick worker uses a more traditional approach. 

They carefully grade the strength of mortar throughout the building, taking into account the different stresses and conditions that each area may face. By doing so, they ensure that the structure will remain strong and durable for many years to come.

How Is A Heritage Wall Repaired?

Heritage brick repair is a complex process that differs based on the needs of the historic property.

It starts with extensive surveying, with the masonry units numbered and photographed, to be replaced with exact replacements made with either the original material or an approved substitute aided by advice from Historic England

When it comes to repairing a damaged wall, the process can be quite intricate in order to ensure the masonry is not further damaged. If individual bricks need to be replaced, they must be carefully sawn out in order to avoid any collateral damage. If one side of the brick is still intact, it can be turned around so that the undamaged side is facing outwards. 

As the replacement process continues, each new brick must be expertly bedded back into the wall with a lime mortar that matches the existing masonry. By taking care in the replacement process, the wall can be restored to its former glory without causing any additional harm in the process.