As we march ahead with our Bronze Age roundhouse construction, Projects Co-ordinator Trevor Creighton updates us on the latest progress on the build. The posts are in the ground, the lintels are going up and we even try a spot of bronze casting.
Our third Operation Nightingale roundhouse building sessions took place over the 19th and 20th of May. The team picked up from where we left off last time with more timber working. Our roundhouse will have a post and lintel frame to support the roof. Post and lintel constructions have vertical posts secured in postholes in the ground. The lintels are horizontal beams, which are jointed to the tops of, and span the gap between, adjacent posts. For a good example of a post and lintel structure look no further than the massive central ‘trilithons’ of Stone Henge!
The posts had already been completed during the previous session, so work began on the lintels. Treewright Darren was again on hand to instruct and supervise the splitting - or ‘cleaving’ - of lengths of oak trunks, which then had bark and some soft sapwood stripped to leave a neat plank. The plank is cut to the length required and holes are chiselled into them near each end, at the precise distance to allow them to drop over the tusk tenons on the top of each post (see the previous blog for a description of making the tusk tenons). Once all of the posts are joined in this way we will have a circle of posts and lintels ready to take the weight of a thatched roof.
You might be wondering how we know that the original was built this way. The answer is surprisingly simple – we don’t! As with almost any archaeology, virtually everything that was is gone. We have to make imaginative leaps from what is left to try and understand what was there. What the Operation Nightingale team found in the original excavation was a series of postholes set around in a circle. Archaeologists are very familiar with roundhouses. They were the dominant form of domestic building in Britain and Ireland from the late Stone Age all the way through until, in some places, the Roman period, in others well beyond. As an interesting aside, there is little or no evidence for roundhouses in northern Europe (at least, north of Brittany) during this period. I wonder why and I’m open to your suggestions!
So, if you find a circle of posts when excavating in Britain you have probably uncovered a roundhouse. That helps us with our first leap of faith – if it was a roundhouse it probably had a roof, walls and a doorway. Beyond that, there is little to go on. In later blogs we’ll look at a number of the other assumptions we are making about our building. Somewhat paradoxically, some of those assumptions are informed by what is not in the archaeology!
But, sticking to the present, given that we have evidence for a circle of upright posts, the simplest assumption is that they supported lintels which, in turn, supported the roof.
By the end of the Friday several of the lintels had been completed, the circle of posts installed in the ground and some of the lintels fixed to the tusk tenons. The walls are around 1.2m high, with a slightly higher doorway to make it a little easier to enter. We are all set up now to finish the remaining lintels and should have the entire post and lintel frame complete at the end of the next session of building. You might be wondering why, in a roundhouse that’s only about 6.5 metres across, we have chosen to build such low walls? Well, that’s one of those things we have determined from what is not in the archaeology. The official term is ‘assumption’ but you might prefer ‘guess’. In any event, I’ll leave that discussion for another day.
On the Friday, the 21st we took time out from our busy building schedule to have a look at another aspect of the Bronze Age – bronze casting. Following on neatly from our previous workshop, where we explored the alchemy of smelting bronze from ores of copper and tin, this week we were joined by James Clift, who demonstrated the art of casting. James does many casting workshops at Butser and he is the perfect person to initiate our team into the mysteries of bronze work. James has an air of the wizard about him, an air reinforced when the golden, molten metal that emerges from his furnace is transformed into a smouldering axe to be plucked from its mould and doused in a boiling, steaming cauldron of water. Thanks to James for a fantastic workshop, which delivered four axe heads. Those axes are replicas of the same original from which our working bronze age axes were cast. So now we have the complete biography of a Bronze Age axe – from raw ores to finished product. Now it’s time to get back to those tools and crack on with the next phase of the build.
