The idea of lovingly restoring a period property to its former glory or designing a characterful new build from the ground up is an exciting one. It gives us the chance to unleash our creative potential and build something beautiful that speaks to us on a personal level and will stand the test of time.
The headline specification choices for a build will usually attract the most attention and debate, but it is the attention bestowed on the finer details which can really make or break a project. Hours can be spent deliberating over the perfect brick choice only for the mortar to be hastily chosen as something of an afterthought.
Well we’re here to shout it from the roof tops – mortar matters! From traditional heritage lime mortar to a basic sand and cement mix, each has its place and each has something different to offer. However, when it comes to conservation and restoration, heritage lime mortar is often the material of choice.
What is mortar?
Simply put, mortar is the material that separates the individual courses of brickwork from one another. It acts as a sealant, it binds the bricks together and it helps to iron out any irregularities between courses of bricks.
Modern buildings will typically use a sand and cement mortar as it is easy to work with, quick setting and has high compressive strength.
Heritage lime mortar
By contrast heritage lime mortar was the mortar of choice prior to the introduction of Portland cement in the 19th century. The Ancient Egyptians were the first to use lime mortars as far back as 2560 BC, and since then they have been used throughout the world with the vast majority of pre 19th century masonry buildings in Europe and Asia being built using heritage lime mortar.
Lime mortar is composed of lime (hydraulic, or non-hydraulic), water and an aggregate such as sand. Hydraulic lime sets by reaction with water known as hydration, so it can set under water. Non-hydraulic lime sets by carbonatation and so needs exposure to carbon dioxide in the air to set.
It is only relatively recently that that we have come to really understand the remarkable durability of heritage lime mortar as a building material, with scientific testing confirming what was perhaps obvious from the vast number of historic buildings that remain standing today.
The advantages of heritage lime mortar
There are many reasons to choose a traditional heritage lime mortar for a conservation or restoration project.
When working with handmade bricks lime mortar is a necessity. It binds gently and allows for natural movement which is an advantage with softer brickwork.
Cement based mortars are not recommended in the repair and restoration of brick and stone-built structures originally built using lime mortar as they are often stronger than the masonry. If movement occurs it can cause the cement to pull away some of the masonry material allowing water ingress eventually resulting in the peeling, flaking or “blowing out” of the face of the brick.
By contrast lime mortar is more malleable and will often produce microcracks if the movement is small. The action of “free lime” allows these microcracks to recrystalise, effectively self-healing the damaged area.
Another advantage of heritage lime mortar is its breathability. It is more porous than cement mortars, and it wicks any dampness in the wall to the surface where it evaporates reducing the risk of trapped moisture and consequent damage to the building fabric. Cement, by contrast, is less porous than soft brick, so damp issues are liable to cause salt formation and spalling of the brickwork.
An authentically beautiful finish
When dealing with a period property renovation authenticity is key and our handmade bricks and heritage lime mortar work perfectly together to ensure an authentic solution where traditional materials are required. They work perfectly with new builds too.
The unique properties of heritage lime mortar as a building material can certainly be a great advantage, but the way the material looks is the key to achieving a beautiful and convincing result.
So whether it’s a characterful modern new build home or on old period property restoration – mortar makes a difference!
