Cob Wall Rebuild in Cornwall – Week 1

It has been busy down at the cob wall rebuild in Cornwall this week. The weather has been great, which has allowed for good progress to the preparations and despite a couple of unexpected (but interesting) findings we are on schedule to get the cob masse on the wall this week.

One of our first tasks this week was to make some cob bricks. These cob bricks will take approx. 10 days to dry-out and will be used for cob repairs to an existing cob wall nearby. We will still require some more and the cob brick making will continue into next week.

Another job needing doing was preparing the existing cob wall on the north elevation to accept our new cob. Joining new cob to old is not a science, however there are a few fundamentals to ensure an effective ‘join’. So, we have raked-back the existing cob to an angle of 12-15 degrees.

When new cob is layered onto the stone plinth there will now be no vertical joint….important because of shrinkage.

At the south end of the cob walling a door opening is proposed. To ensure an effective ‘reveal’, cob blocks will be used and not wet cob. But first some of the failed/failing existing cob was removed to accommodate for the cob blocks.

Whilst preparing this cob wall to accept the cob blocks, 2 very large stones appeared! This ‘method’ of introducing substantial stone to the cob wall base ie the first 3′ or so, is not something I’ve come across before. Interestingly, there is similar on the old north wall, so it is clear that this constructional practice was adopted here. Why? All will be revealed in my next Blog!