‘Dial M for Mud’ - Butser Projects Co-ordinator Sue Webber explains the detective work involved in solving the mystery of the Bronze Age roundhouse walls, giving the rationale behind our varied approaches to the wall construction.

After many discussions, some late at night, some early in morning the consensus was that the Bronze Age house could have had mud walls. Then we had to decide what type of mud walls they would be. But before we go on there let’s recap a little on the archaeology.

The excavation at Dunch Hill that we are basing this building on gave us post holes – where they are in relation to one another, the diameter of the posts and the depth. That gave us the layout for the building. What we don’t have is any indication of the materials that the walls were built from. This detective mystery leaves us few clues, Dr Watson. The material evidence may have been robbed, rubbed out or rained away. 

If it was robbed, then good building material may well have been re-used in the best Bronze Age recycling practice and taken away for another structure.

Later ploughing may have rubbed out the evidence of wall structure and materials, leaving no trace for the archaeological Holmes.

The third R, rain, means that our friend, the weather may have played a part dissolving material and returning it to the earth.

So, Dr Watson, what next?

What materials would have been available to Bronze Age builders on Salisbury Plain? The soil is a thin layer over chalk. There was evidence of some woodland, pasture and crop fields. What they didn’t have locally was building stone (except for the Stonehenge sarcens of course), or deep turf to play with.

Modern-built Iron Age roundhouses at Butser and elsewhere are often constructed with wattle and daub walls. These are usually hazel or willow woven wattles covered in daub made with the childrens’ favourite recipe – mud, straw, water and POO! Wattle and daub is a possibility for this house, although there are no small postholes to show evidence of wattle uprights. Are you keeping up Watson?

Certainly Holmes, the butler in the library?

Here at Butser we want to try something different, because we know about wattle and daub but we don’t have as much experience of mud walls.

The options that seemed plausible included turf walls, cobb walls or earth walls. And since they all had their motivation and opportunity it was hard to pin one down as the culprit.

So, instead of a single perpetrator we decided to try them all and find out which was guilty, sorry, the best option.

Turf walls, are generally made where there is deep soil that can be cut into thick turfs, and sometimes interlayered with stone. The Salisbury Plain turf, and the Butser turf, is thin but we saved what we took when we cleared the site and built it into a sloping wall with a wide base, against a light wattle structure inside.

Cobb walls, are often built with boots (some sort of foundation) and a bonnet (a covering roof). We had a clunch or cobb-walled building at Butser which proved to be very durable and took strong men with sledgehammers to bring it down. The underlying chalk on the site gave us a good reason to try making cobb with broken up chalk, water and straw. 

Earth walls, are another option, so again we made a light-weight wattle structure to pile earth against.

Making the building with a variety of techniques and materials means that we will have a better understanding of the options Bronze Age builders might have had. As the build progresses we will see how these walls perform and later in the building’s life will have even more information about their durability. And one day, many years in the future, we will see what these walls leave behind.

So, clear as mud Watson?

To support our Bronze Age Roundhouse project with Operation Nightingale and discover more behind the scenes footage of the build head to at www.butserplus.com where we are releasing weekly video episodes about work and projects at the farm. Thank you!