Cob wall rebuilds in Cornwall

Oftentimes when cob walling in Cornwall needs attention it is generally standard practice to introduce a cob repair. In accordance with the (Revised) National Planning Policy Framework 2018 and (if applicable) Section 8 of the Planning (Listed Buildings and Conservation Areas) Act 1990, more weight should be directed toward repair rather than replace. However, if replacement is the only less harmful course of action to safeguard and assume continuance of historic assets, rebuilding of the cob wall should use appropriate and proportionate methods and materials.

There are several ways in which to rebuild a cob wall; construction materials could be cob blocks, wet cob or rammed earth. Each of these methods have both positive and negative attributes to its immediate setting and/or the local environment, therefore any proposed rebuilding of a cob wall must be first professionally assessed and ultimately managed and executed in accordance with current legislation and regulations. You can contact us, in confidence, if you have ANY uncertainty, queries or want to question sought advice regarding cob walls.

Why do some cob walls in Cornwall fail?

A considerably large number of Cornish dwellings, farmsteads and boundary walls are constructed from cob or part cob and stone. Admittedly, some are not always easy to recognise and many, for the general observer may go undetected for a lifetime or more. On the whole though, most guardians of these structures are aware of the presence of cob and it is reassuring that there is an upturn in trend for custodians to seek specialist advice when something goes wrong. This may be the case now however, but we must consider the implications and sometimes sour consequences of previous attempts at reparatory works to cob walls in Cornwall that may have been undertaken with unfamiliarity and/or inexperience. Most frequently, cob wall failings can be attributed to the use of inappropriate materials such as cementitious products and/or silicone-based waterproofing systems. The introduction or application of these impermeable materials are proven to be detrimental to historic substrates and fundamental in preventing crucial breathability to old, solid walling……..a wet cob wall is ineffectual (see Damp Walls). Cob wall failures also occur whereby the actual cob isn’t the problem. A common example is roof collapse. Structural timbers that assist in distributing roof loads may have suffered from rot or fatigue, weakening them from purpose and eventually ‘pushing’ the cob walling outwards. Finally, we mustn’t discount neglect. An unhealthy quantity of cob walls lay abandoned or forgotten about in Cornwall and are generally [un]recognisable by the vast amounts of vegetation growing over them. It’s conclusive that bare cob will tolerate a certain measure of rain, however, intrusive (and destructive) foliage such as ivy, will devastate the wall. So, these are a few commonplace reasons for cob wall failures in Cornwall, however there are many other contributory factors that can and do affect or influence the wellbeing of our cob walls.

For all your cob rebuilding requirements or queries, please visit our cob specialist contact details page.