The Critical Role of Voids and Breathability in Historic Masonry
For architects, preservation companies, and those managing historic assets, understanding the science behind lime mortar is fundamental to long-term property survival. Because to be honest, it’s not just about appearances. It’s about building physics.
And that’s why at K Blythin Stonemasons, we want to be able to share our expertise. With over 60 years of experience in restoring the natural function of historic walls using meticulous, historically accurate techniques, let’s delve into why voids and breathability are so crucial in historic masonry.
Firstly, The Science of Breathability
Historic masonry walls are fundamentally designed to manage moisture passively. Lime mortar is highly porous due to its high void volume (air pockets). And this feature is critical because it allows moisture absorbed by the wall (from rain or condensation) to evaporate outwards through the mortar joints. This essential breathability is what protects the masonry from decay.
Contrast this with non-porous cement, which traps moisture inside the wall. The moisture is then forced to evaporate through the face of the softer brick or stone, leading to destruction (spalling) of the valuable historic fabric. With that in mind, lime mortar’s structure ensures preservation by keeping the wall dry and healthy.
Secondly, Flexibility Protects Structure
Historic buildings are designed to settle and move incrementally over time. Hence, with lime mortar’s flexibility and lower compressive strength, it’ll allow the building to adapt to this movement without cracking.
When rigid cement is used, any movement causes rigid cracking, often transferring stress into the harder, more valuable stone or brick itself, leading to costly structural damage. However, with lime, it acts as the sacrificial element that absorbs movement and protects the expensive masonry.
Thirdly, Guaranteed Durability and Longevity
Aside from being flexible and breathable, lime has also been know to be ‘self-healing’. With regenerative abilities that allows it to repair small cracks over time, the process is called ‘carbonation’, where carbon dioxide from the air is absorbed by the lime to form calcium carbonate. Thus, filling voids, maintaining the building’s integrity and ensuring long-term durability.
Which comes back to our approach at K. Blythin, where we focus on ensuring this quality. By allowing the walls to breathe and adapt, we significantly reduce the risk of decay and damage to the masonry fabric. This precision work not only secures the structure but also revitalises the property’s appearance, giving it the authentic, well-cared-for look required for historical significance.
Hence, choose K. Blythin for a scientific, precise approach that guarantees the long-term health and longevity of your historic asset.
To learn more, get in touch with us at at 07877 812 669 or info@kblythinstonemasons.co.uk.
Who is K. Blythin?
K. Blythin Brick & Stonework Ltd is an experienced, family-run business from Chester with over 60 years of combined experience in the brick and stone-working trade.
We handle all manner of brickwork and stonework from lime mortar pointing & brick laying to paving & drystone walls. Rest assured, we’re qualified in heritage practices, so this means we can assist with restoration and improvements to listed properties and buildings of historical importance. So give us a call and let an expert guarantee the longevity of your historic structure.
