Burnt Daub and the Ghost of Wattle

It’s re-run week! I’ve gone back to my first month of blogging and found some good stuff. Here’s a piece from 20 December 2005.


i-16d79a02acd1eb682b82448f040ce66d-daub.jpg

Lately I’ve been washing a lot of ruined building materials, debris from a house fire 2000 years ago.

Me, my friend Howard and his students excavated a Viking Period boat burial in Östergötland last summer. It dated from the 9th century AD and was sitting on the remains of a settlement from the 1st century BC. We weren’t there to study that period, but we ended up with a shitload of burnt daub. Thousands of pieces of fired clay with imprints of twigs and straw.

Wattle and daub is a cheap and sturdy technique for building house walls. The roof of your 1st century BC house has its own supporting posts. Between the eaves and the ground, you fix slim stakes where you want the wall, and then you weave thin withes between the stakes making a basketwork screen: wattle. You then mix clay with straw and dung and daub the wattle from both sides. Stays wind-proof for decades. Then, when your house burns down, as it is likely to do when you have no chimney and warlike neighbours, the daub turns into coarse ceramic chunks. Which archaeologists will collect, wash, dry, weigh and photograph.

This is boring and pointless. We collect the stuff because it’s clearly artificial and has a funny shape. It occurs in humongous quantities, 100s of kilograms from one site in some cases. But we have yet to see any interesting information about life in the past come out of burnt daub. At excavations, we look at it and say, “There’s been a wattle-and-daub structure here, and it’s burnt down”. And this is as far as burnt daub takes us.

There’s an on-going discussion about this issue in contract archaeology. A few years from now the standard procedure will probably be to document where the daub was and how much it weighed, then collect, say, ten of the largest and most intricate pieces from each context, and dump the rest. But I didn’t feel I had enough clout to try to set a precedent with last summer’s dig. So I’m doing the washing up.

Addendum 4 January: a shitload is here defined as roughly 18.1 kilogrammes.

[More about , ; ]

Comments

  1. #1 Janne
    November 19, 2010

    Naive question, but shouldn’t you be able to find physical remnants of the builders in the daub? Hand and fingerprints, hair, skin debris and so on? Maybe enough for DNA testing if you want to start getting fancy with tracing lineages. Seeds, pollen, insects and so on should be interesting to figure the microclimate in the area at the time.

    So if you’re just going to throw most of it away, perhaps it could be worth thinking about what you could find by breaking it and analysing the contents?

  2. #2 Josefine Bican
    November 19, 2010

    Maybe you find wattle and daub boring and not saying anything about life in the past – but you are so wrong. If you bother to look at it, it might tell you about the construction of the buildings and the aspects and maybe the meaning of the architecture. What are the pieces like on the other side?

  3. #3 Don
    November 19, 2010

    Martin: Tell us more about your father’s building project. Don

  4. #4 stripey_cat
    November 19, 2010

    I’m with Martin here: it’s been burned, so the chances of getting any useful environmnetal data are slim. You might find seed-cavities or suchlike in the daub that’d tell you the composition of the meadows the dung-producing creatures grazed, but middens (and natural deposits like bogs or lake-sediments) will provide much more data more easily. Also, the thought of prepping kilos of ceramic for microscopy, in return for data that confirms what we already know of the local environments, *does not appeal*.

    In terms of architecture, it’s smoothed on both sides, generally not painted or limewashed, sometimes thicker or more patched on the side that the worst storms come from, and the hurdles are made from whatever coppice-woods are locally available. If you really like jigsaw puzzles, you could try piecing together a whole wall, and you’d find it mirrors the shape of the post-holes you’ve already found. I guess it could also tell you roof-height at the wall, if that’s of vital interest to you. Maybe if you’ve found a vertical loom resting against the rafters and want to know how tall it was (so you could have a stab at maximum height of the women)? The stuff is nearly as uninteresting as breezeblocks. Heck, even breezeblocks might be able to tell you something about trade and distribution of manufactured materials! In contrast, w-a-d is made in situ from widely-available, cheap materials, so really it only tells you of the presence of brush and herbivores. Also, it isn’t the element that defines the shape or structure of the building – that falls to the timber frame supporting the roof (and in some constructions bracing the walls against the wind). If there’s surface decoration you might find it (assuming it’s something that’ll have burnt into the clay rather than burned off), but it’s mostly used for low-status buildings that weren’t likely to be fancy; also, the mere existence of decoration isn’t that interesting anyway!

  5. #5 rg
    November 19, 2010

    I agree/disagree. Daub can be a pain in the ass to handle, both in the lab and from a curation standpoint. However, those impressions can tell us much about seasonality, availability of and/or selectivity of local resources, and even details about specific building elements. In the SE U.S. we’ve used daub impressions to get a better understanding of roof pitch (something you can probably better appreciate, Martin, having recently been on your Dad’s!). The clay impressed at the intersection of walls, support timbers, and roof joists can be used (post-firing, of course) to get the precise angle of the roof. Their misfortune is archaeology’s gain. Very useful information as there is little in the early historic record to tell us about houses of the tail-end of the prehistoric…

  6. #6 Phillip IV
    November 19, 2010

    I’m for preserving any and all kinds of relics – information is information. Even if the information contained in the daubs can be reasonably called completely worthless today, the 1-in-100 cases where such information might latter be made invaluable by completely unforeseeable developments can be fully worth the effort for the 99 cases in which the information will never amount to anything.

    Or, the other way round, consider the amount of information that was lost by carelessly discarding relics that were, at the time of their discovery, quite reasonably considered worthless (like deteriorated papyri), but would be valuable nowadays, if they were still around.

    a shitload is here defined as roughly 18.1 kilogrammes

    I dunno, but you might want to cut back on the fibers. ._.

  7. #7 Thomas Ivarsson
    November 19, 2010

    My grandfather had a small farm in the Bjäre peninsula in Scania/Sweden and he had a great collection of stone axes of flinstone. There was areas where these axes appeared when he ploughed his fields.

    Each item carries it own history but how many do you have to archive for the future?

  8. #8 murmel.jones
    November 19, 2010

    Daub fragments might appear boring at first glance, but they can contain a lot of information. Some years ago, we archived about a hundred boxes of daub fragments from an iron age site here in Southern Germany. Right now there’s a colleague of mine analyzing it, and he already found evidence for several different forms of wall construction, angled pieces from window- or door-frames, fragments from ovens and fireplaces, whitewashed and painted wall fragments, pieces with plant and seed impressions…
    so we judge it worthwhile to keep and archive most of the daub fragments we find.

  9. #9 Art
    November 19, 2010

    On the one hand the prospect of examining a huge amount of undifferentiated material in fine detail and documenting what has already been well explained sounds fruitless it also has to be noted that science is often in the details. Details that are often overlooked until someone takes the time and effort to examine what offhand looks like a vast amount of sameness in fine detail.

    While it might be assumed the dust and pollen would be burned out of the mud farther up the walls it might be found that such things remain intact on the lower walls where heat might not be so intense. If pollen was trapped what does this say from year to year. Does it really parallel the existing records?

    I’m friends with a PhD in physical chemistry whose thesis was on how a particular chemical reaction didn’t produce the useful, and desired, result. A swing and a miss. But a very well documented swing. What doesn’t work is also science.

    Then again pollen deposited when daubing would likely be a record of the plant life during a particular season. I kind of doubt much daubing gets done in the nine months of northern winter. Maybe small repairs.

    The mud would also document any change in form of the materials used. Would this vary by growing season? Wet versus dry years? Would war or disease change the size or type of materials used? A community crippled by war, disease or famine might resort to less than ideal materials.

    If dung was a component would its proportion change with the fortunes of the people doing the daubing? I don’t know but wouldn’t more cattle, and more cattle dung, imply prosperity?

    Life, as an outline, is always simple. You’re born, live, die. It is the details that are interesting.

  10. #10 Anatoly
    November 19, 2010

    I’m with Martin on this one. A lot of the studies that can be done on wattle and daub remains can be done with a representative sample (say – 10%?) until somebody presents some spectacular study utilizing every single small fragment of it.

    Working in the contract archaeology in Ontario, we have the opposite problem. In our case, the material gets preserved most often is brick from Euro-Canadian sites and in the contract world we keep none of it (except in rare cases like samples from an industrial brick factory). There are lots of fascinating studies that can be done on brick and in research archaeology some do keep representative samples. However keeping and processing every single piece is overkill.

  11. #11 dzdt
    November 22, 2010

    Hmmm… does luminescence dating work for burnt daub?

  12. #12 John
    November 23, 2010

    Our prehistoric roundhouses in Ireland are built in a similar fashion but we do not get shitloads of daub. We get very little daub. I wonder what taphonomic processes are at play here.

    We have started to see more clay walls though. or the spaces where clay walls had been.

  13. #13 Martin R
    November 26, 2010

    Janne, good ideas all.

    Josefine, most pieces are featureless crumbs. The other side of the pieces in the picture is usually flat, but sometimes you get bits were two wicker mats have overlapped.

    Don, I’ll ask my dad if I can put up some plans and elevations here on the blog.

  14. #14 Martin R
    November 26, 2010

    you could have a stab at maximum height of the women

    That’s unlikely to satisfy anyone. I usually aim at the middle. Hurh, hurh.

    I’m for preserving any and all kinds of relics – information is information

    That is true in the ideal situation where we have unlimited study time and labour available for your work at a site. Since this ideal is never attained, we must prioritise. My thinking about daub has not changed in this respect in the past five years.

    Each item carries it own history but how many do you have to archive for the future?

    You keep the stuff you find informative plus some that you hope will become informative one day. You never keep everything.

  15. #15 Martin R
    November 26, 2010

    does luminescence dating work for burnt daub

    I believe it does. But since daub only survives when burnt, there is usually no shortage of carbon for dating at such a site.

The site is currently under maintenance and will be back shortly. New comments have been disabled during this time, please check back soon.