Cob Repairs Cornwall Leslie Cornell
Cob is an ancient building material that may have been used for building since prehistoric times. Some of the oldest man-made structures are composed of rammed earth and cob.
Cob structures can be found in a variety of climates across the globe; In the UK it is most strongly associated with counties of Devon and Cornwall in the West Country and Finisterre in Brittany where many homes have survived over 500 years and are still inhabited today.
Traditionally, English cob was made by mixing the clay-based subsoil with sand, straw and water using oxen to trample it. Leslie Cornell Building Restoration repair cob in Cornwall using traditional methods...
Cob Repairs Cornwall – Leslie Cornell Cob in Cornwall – Cob Specialist Cornwall
See our articles below for more detailed explanation and images of our work and methods...
Cob Specialist Cornwall
The conservation of Historic Cob Buildings in Cornwall requires a sympathetic and positive approach, and this is what Leslie Cornell Building Restoration Ltd are specialists in achieving.
There are hundreds of Cob buildings and boundary walls throughout Cornwall and with our passion, care and attention for these constructions, they will be there to enjoy for many more years to come.
Leslie Cornell Building Restoration Ltd have built up a vast portfolio of expertise and experience in the maintenance of historic buildings in Cornwall, and Cob buildings are one of our specialities.
We are always available to discuss any Cob building projects in Cornwall, and if this is something you think we can help you with please Contact Us.
For more information about the terminology used within this website, please have a look at our Glossary.
If you have any questions about Historic Building Restoration in Cornwall, please visit our FAQ page.
Cob Specialist Cornwall - Leslie Cornell Cob Specialist - Leslie Cornell
Cob in Cornwall Specialists
There are many hundreds of buildings and boundary walls constructed with cob in Cornwall. Our 2006/07 survey revealed several large clusters, indicating the prolific use of cob around the county.
As well as these clusters of cob buildings, small groups and isolated one offs, were also unveiled.
Shuttering was used where door openings were required.
Lintels for windows would be buried in the cob at the appropriate height and the cob would be removed below each lintel at a later stage. There is some evidence to suggest that the size of the window opening, or even having a window at all, depended on affordability, availability or even the window taxation period during the 1700's. We discovered oak lintels buried in the wall on three separate projects, supporting the theory that the luxury of a window was not always possible.
What is Cob?
Cob is a mixture of clayey sub-soil, straw and water.
When these elements are combined correctly, they form a workable building medium. The characteristics of these elements, when successfully blended, deployed and established, will generate a homogenous material that is strong, insulative and unquestionably, sustainable.
As a guideline, the ratio of soil, straw and water = 4 – 3 – 1 by volume.
As Cob Specialists we pride ourselves on our knowledge and understanding of this fantastic building material.
To achieve a successful and long-lasting repair a full understanding of the substrate and structure is required. Our initial question is, 'What has caused the damage?'.
There are many reasons for varying states of disrepair – water penetration, failed cladding, failed roof timbers, bees, subsidence. These, we have found, are the most common causes.
Deep hollows and rat runs, for example, can be quite easily and quickly repaired with the use of pre-formed cob bricks and/or blocks.
Using a Lime mortar as a binder, shrinkage is negligible. Where rat runs are numerous, it would be impractical, and could possibly compromise the stability of the wall, where these would have to be 'chased out' to accommodate so many cob bricks and/or cob blocks.
In these instances, a Lime mortar 'slurry' can be poured into the holes, plugging them with hessian while working up the wall. Once the lime has set the hessian is removed and there is scope to chase out for the cob brick or blocks on the face of the wall.
A properly maintained cob wall can last for hundreds of years, but if it is neglected it will start to deteriorate and may need localised repairs or rebuilding.
Our cob rebuilds start with making sure the foundations beneath the walls are appropriate for the load. We then start on the rebuild by re-introducing the stonework plinth to prevent the cob having direct contact with the ground.