Up until a thousand years ago, almost all buildings in Scandinavia through the ages had roof-supporting posts dug into the ground. Postholes are lovely things: they’re deep enough for at least the bottom end to survive heavy ploughing, they trap a lot of interesting stuff while a house is being built – lived in – torn down, and their layout across the site lets you reconstruct the building in great detail.
When you machine off the ploughsoil from a site and find a posthole building foundation, it is common to mark the postholes with coloured sticks, paper plates or shaving foam and photograph the whole thing, preferably from some vantage point such as the scoop of an excavator or a low-flying aeroplane. This gives you a good intuitive idea of the house’s placement in the landscape.
In the above picture (shot probably by his colleague Stina), Lars L of Arkland has marked out the foundations of a 12th century banquet hall at Varla in SW Sweden. And he’s done it in a novel way: using a visiting class of school kids. Most of the kids are standing on postholes belonging to the walls: these are usually small and shallow as all they had to support was the wattle-and-daub wall. In this case, however, we’re seeing a transitional structure type where the roof no longer has dedicated support posts inside the house, being instead supported by the walls. The next step was to do away with postholes entirely and anchor the wall posts in a horizontal sill-frame of wooden beams supported on a rectangle of stones sitting on top of the ground surface. That was a sad development in structural engineering, as a sill-frame building usually leaves no excavatable traces in ploughland once the farmer has carted off the sill stones.
The inside of a house with a wall-supported roof was a novelty, being the first time you could enter a large building in Scandinavia and see an airy space without roof-supporting posts everywhere. Here’s a brief rundown of the rural Scandy long house’s development.
- Early Neolithic, 4000 BC. Long houses appear, roof supported by a single line of posts down the centre of the house: interior thus separated into two aisles.
- Late Bronze Age, 1100 BC. Two-aisled house gives way to three-aisled house, with two lines of posts down the centre. Each building is divided into several functional units, with one half a byre and the other for living quarters.
- Viking Period, AD 800. Long houses survive mainly as banqueting halls, while the various units of the earlier multifunctional houses are built as separate small houses without interior roof supports. Sill frames appear alongside posthole walls.
- High Middle Ages, AD 1100. Long houses increasingly rare, small sill-frame buildings become the rule.