LESSBIG attended 1 day of a 2 day course, run by The Society for the Protection of Ancient Buildings (SPAB) in Slawston, Leicestershire on the 30th of April. There were a number of very informative talks and some hands-on repairs of an earth walled stable block.
Read on for lots more pics and notes:
First of all, the talks
Rather than risk getting people mixed up, I’ll just list some of the factoids that stuck with me and say they all came from these three speakers:. Jason Mordan, Nottinghamshire County Council; Stafford Holmes, Architect; Anthony Goode, Conservation Builder and during a tea break, Jenny Clarke and John Acres shared their experience of undertaking repair on one of their mud walls.
Anyway… facts away!
– The Geology of Britain viewer is an interesting (if a bit difficult for the newcomer) online map through which you can see the different types of stone and minerals beneath your feet. From this we can see why certain areas took to earth building more than others, it depends on whats available of course. Also things like Earthquakes and Boreholes.
– An earth built dovecote in Flintham, Nottinghamshire was featured on an episode of Countryfile. (Sorry I can’t find any pics, but here’s a link to the ancient monument scheduling). It was partially at threat because of Ivy growing on the top; ironically, the ivy may have been planted there back when it was originally built in order to act as a roof for the structure.
– The ICSEAH (International Scientific Committee on Earthen Architectural Heritage) continue to host a number of conferences around the world. (next one is in Korea, any one happen to be in that neck of the woods? ;) Their website is worth a visit, the ‘Terra’ conferences I had heard mentioned a few times but it’s a shame I can’t seem to find much more about them online.
– The work of HANDS (an NGO in Pakistan) who, amongst other things, have helped rebuilding after the 2010 floods. The benefits of earth being relatively easy, cheap and low tech to work with; which helps ensure that it can be maintained, repaired and rebuilt by the people working there. It’s easy to turn to cement thinking it will be stronger, but it’s heavy and costly to ship and repair.
– Cement and earth are not best of friends as, generally speaking, earth ‘breathes’ and cement doesn’t. There are numerous examples of a cement render being applied to fix an older earth wall, where, over time, the render will ‘balloon’ out and fall off.
– Some other random characteristics to be aware of; it’s possible to compress a drier mix more than a wet mix; the higher the clay content, the more shrinkage is likely to occur; you might think a cement mixer might be a good idea for mixing earth and straw but in practice it just bunches up.
– Barley straw is thought to be preferable for cob as its coarser texture helps grip the mud, whereas the smoother Wheat straw can be preferred for roof thatching; if not using some kind of reed.
– And finally, the Mosque of Djenne in Mali. One of the most impressive earth buildings standing in the world. The current structure was actually finished in 1907, so more recent than you might think at first glance (link)
Now the messy stuff… the cob wall, the bricks and the rammed earth wall.
Hands-on Part 1: The Cob Wall
Hands-on Part 2: The Bricks
Hands-on Part 3: The Rammed Earth Wall
You can read more about the whole course from one of SPABs own team here (link)
The finished wall eventually looked like this, what a beaut:
Thanks once again to SPAB for this fun, informative and well organised day, and a special thanks to Anthony Goode, the East Midlands local ‘mud man’!