Roundhouses

Post holes and platforms
When archaeologists talk about structures, many people imagine standing buildings, but the reality is that most of the time they are referring simply to the remaining evidence of structures, such as foundations and post holes. Apart from some rare stone-walled buildings, no roundhouses from the Bronze or Iron ages survive above ground today.

Sometimes the only evidence for a house at ground level consists of a slight impression on a hillside. These are terraces where a platform has been excavated out of the slope to provide a solid, level surface for building. Most of the evidence is revealed when excavation takes place and we can find post holes.

Post holes are vertical, usually circular holes that once acted as sockets into which upright posts were inserted. Some of the bigger examples can even have a slot, or ramp, cut into the side as a means of helping to erect the post. Post holes can represent fence lines, ritual enclosures, industrial activity or structures.

Archaeologists look at the distribution, size and depth of post holes to try to interpret their original purpose. This can cause all sorts of problems, especially if no dating evidence is forthcoming. Some sites reveal hundreds of features and it can almost be a case of joining the dots to see what they could mean. Other sites have distinct circles and clearly determined lines. If datable evidence, such as pottery, can be found in the 'back fill', or packing, of the post hole then the chronology of the site can sometimes be determined.

Other roundhouse features and finds
Apart from post holes and platforms, other features in the ground can highlight the site of a roundhouse. These include burnt areas where a hearth would have been, storage pits and even drainage or drip gullies carved out to carry rain water away from the house (as found at Waddon, Dorset, where Time Team excavated in the 2000 series).

Artefactual evidence can include pottery, stone or clay weights used with a loom, stone tools and even carbonised wheat grains. Sometimes even the distribution of flakes from making stone tools can be studied to determine where in the house the maker would have sat. Under normal conditions, it is mostly non-organic artefacts that survive. However, on some waterlogged sites, such as Flag Fen, which also featured in Time Team's 2000 series, evidence has been found of leather, fabrics, food and wood. By combining all the evidence we can try to picture what one of these houses would have looked like.

While there are some slight regional differences in style and foundation plan, most roundhouses tend to follow a similar design. This variation on the same theme is probably due to each house being built by the people who lived in it and not by a group of specialist house builders. Everyone had the same sorts of problems in construction at the time, so the round shape is probably the result of decades of accumulated experience.

Raising the roof
We know from post-hole plans that the majority of roundhouses were constructed by using large upright posts to support the roof. Walls were made by weaving lengths of wood between stakes to produce wattle screens, such as the hazel hurdles used in Time Team's reconstruction of a roundhouse on Salisbury Plain. These were then covered in mud, clay, dung or a mixture of all three to produce a solid wall.

The main timbers used in construction range from ash and elm to birch and oak. Each of these woods has various advantages, but oak is probably the best material for use in construction. Its oily nature makes it very durable and it can be used soon after felling because it doesn't distort much as it seasons.

By looking at the post-hole plan and considering the various load-bearing properties of different woods of different sizes, assumptions can be made about what kind of roof could be supported by the foundations. It is generally accepted that on top of the upright posts there would have been a ring beam, or plate. This would take the weight of the rafters. The rafters rested on the ring beam and met in the centre, creating a conical roof. Cross ties, or battens, were then secured to strengthen the roof and provide a framework for the roof covering. This could have been turf or thatch, and the technique used for each type would have dictated the durability of the roof. For example, there is an old Irish technique of thatching that lasts two to five years before it needs replacing. By contrast, the modern English style can easily last for 30 years or more.

Roundhouse construction tools and skills
Undoubtedly, roundhouses were not all of the same quality, but we know from preserved timbers that a host of carpentry skills were employed. Different types of joint, such as mortice and tenon, scarf and lap, were used for strength in construction. Examples of carpentry tools have been discovered on various sites. A gouge chisel, saw and adze were found in excavations at the Iron-Age hillfort at Danebury, Hampshire. Experimental archaeology has also proved that the sometimes complicated joints can be cut quite adequately with just the basic stone and bronze tools available in earlier periods.

A common misconception is that roundhouses would have been grubby, uncomfortable places to live. But experiments such as those at Butser Ancient Farm in Hampshire have shown that they can be warm and cosy in winter and cool in the summer, good shelter and generally comfortable.

Size and settlements
The size of roundhouses varied considerably from just a couple of metres to more than 15 metres across. Bronze-Age examples are often found in groups of three or four, possibly representing small extended family farmsteads. There were large community groups in the Iron Age. The economies of these settlements appear to have been based around agriculture with additional industries making them largely self-sufficient. However, trade was well established in both periods and we should consider that skills, as well as objects, could have been bartered.

Some evidence for internal divisions in houses and the grouping of houses in settlements indicates multi-group occupation and this should be considered when trying to construct a model of these ancient societies. The fact that Iron-Age settlements often include boundary lines, and sometimes earthworks, could indicate that there was more emphasis on property ownership and definition between groups in this later age. Whatever the case, the roundhouse remains a symbol of daily life in prehistoric Britain.

There is an excellent series of photographs on the Bodrifty Farm website www.bodrifty.co.uk/BuildingRoundhouse.htm showing the construction of a roundhouse near the site of the Bodrifty Iron-Age Settlement in Cornwall.

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