Paul O'Mahony

26 May 2009

17:07 CEST+02:00

New research has revealed a wooden building in Mora in central Sweden to be the country's oldest wooden residential home.
With the aid of dendrochronology, or tree-ring dating, the Dalarna province's leading museum has shown that the timber used to build the house dates from the year 1237.
"We're delighted. There has been speculation about this since the 1920s and we have drilled and carried out tests twice before, but this is the first time we were able to confirm the date," Jan Raihle, the head of Dalarnas Museum, told The Local.
The house is a so-called eldhus (literally "fire house"), a one-room building with a fireplace in the centre.
Though currently located at Zorns Gammelgård (Old Farm), part of an estate donated to the Swedish State by the artist Anders Zorn (1860-1920), the house has previously been moved at least five times.
The farmyard on the banks of Lake Siljan is made up of around 40 houses and was designed by Anders Zorn to showcase the province's old log building traditions.
Since the mid-1990s, Dalarnas Museum has been working with dendrochronologists to date the province's impressive stock of timber houses from the Middle Ages.
"There are of course very old wooden houses all over Sweden, but Dalarna has by far the most. So far we have dated around 150 houses to the period from the 1200s to the 1500s," said Jan Raihle.
But although the
Mora house is the oldest wooden residential home, it is not the oldest non-religious wooden building in the country: that honour goes to an outhouse attached to Ingatorp Church in Småland in southern Sweden.
Carbon 14 and dendrochronological studies both date the Ingatorp building to 1229, plus or minus ten years.
"It's now used as a shed for lawnmowers and such like but it may originally have been used as a weapons store," said Lennart Grandelius, who carried out the study in association with the University of Lund.


What kinds of houses were used in Sweden in former days?
The dominating house type was the X-joint log house (knuttimmerhus) – houses built with horizontally laid logs, interlocked in the corners.
Sweden has large woodlands so the conditions were right for constructing log houses. There are still a very large number of log houses around in Sweden, especially in the countryside


The Swedish term "knuttimmerhus" is normally translated to X-joint log house or cross-joint log house. The technique is called "knuttimring" and is translated into X-jointing or cross jointing. Other terms are notched corners; log built corners or corner joints.
In our neighboring country Norway X-joint log houses are called "laftehus".


X-joint log houses have been around for a very long time in Sweden. The X-joint building technique began most likely during the 11th to 12th century. The oldest documented evidence of x-joint log houses in Sweden is from the 13th century.
The tradition of building X-joint log houses probably started in the cities and then spread to the countryside. Some historians claim that the Vikings (800 – 1050) were building X-joint log houses but there is no verified evidence of that.
The X-joint technique spread from Eastern Europe to Scandinavia and the timeframe for this is probably the 11th century. 

Log houses are built from logs laid horizontally, row-by-row, and interlocked on the ends with notches, so- called X-joints. This results in very stable and tight houses.

The X-joint technique replaced the earlier type of houses built with framed horizontal boards or planks (skiftesverk). X-joint log houses existed in parallel with houses built with the earlier techniques during the 12th century though. However, in the 13th century the X-joint building technique totally dominated among the wooden houses. 

X-jointing became the traditional way of building houses in most parts of Sweden, both in cities as well in the countryside until the middle of the 1800’s.

Dating Method:
The oldest dated X-joint log houses in Sweden are from the 13th century. The oldest X-joint log building still standing today is
Granhult church , Småland province, which is from the 1220’s. The oldest secular building is a church "häbre" (a log storehouse raised from the ground) in Älvdalen parish, Dalarna province, which dates back to about 1285.
The age of old log buildings is determined with a technique called dendrochronology, which is an analysis of trees
annual-ring growth patterns.
With this method you can determine the year and even the time of the year when the tree was felled provided you have access of a so-called
basic curve (grundkurva) for the region where the tree has grown. By taking samples from different sites and different strata within a particular region, researchers can build a comprehensive historical sequence that becomes a part of the scientific record. According to Göran Rossander (see reference literature list below) Sweden is leading the world in dendrochronology.

Building Technique

By cutting out a groove ("långdrag") underneath each log,
one could get a tight fit between adjacent logs.  

The upper side of the log below was first evened off a bit.
With a special tool called "dragjärn", two parallel cuts were then notched on two adjacent logs. This was done on both the inside as well as the outside of the logs.
A "dragjärn" or scribe in English, was a talon shaped tool with two prongs.
The scribe followed the upper part of the log below alongside the gap and the notch made on the upper log thereby followed the contour of the log below. In other words, the contour of the log below was copied to the log on top of it in a very precise way.
The wood between the notches on the underside of the upper log was then carved out to make it fit smoothly on top of the log below and making the gap between the logs very small (image 3).
In the center of the carved part of the upper log, a lengthwise groove was cut out. The groove was v-shaped and about 3 to 4 cm wide (about 1 ¼ - 1 ¾  inches) and 1.5 to 2 cm deep (about 5/8 - 7/8 inches) (see image 4).
With the groove, the weight of the upper log came to rest on its outer edges against the log below making
a tight fit (image 5). 

Normally the gap between the logs (the groove) was filled with moss or tarred flax (lindrev) to seal the area between the logs.
In order to keep the logs in place they also used dowels (dymlingar), i.e. strong wooden tenons or pegs.


Wood - Pine and Spruce:
The timber normally used for logs was straight pine, but spruce was also used. Pine is an excellent material for this purpose since it normally grows very straight and is relatively resistant against rot.
Spruce rots more readily and has a tendency to twist.
The specie of pine trees ("tall" in Swedish - short vowel) we have in Sweden is the Scots pine
(Pinus sylvestris) (a close relative to Lodgepole pine - Pinus contorta, both have two short needle clusters and almost identical cones with similar woodworking and growth characteristics and grow in similar climates) and the spruce ("gran" in Swedish - long vowel) we have is the Norway spruce (Picea abies).
About half of Sweden is forest land so we had plenty of raw material for log houses. In certain areas like the provinces Värmland, Dalarna, Hälsingland, Medelpad and Ångermanland, forests occupy as much as 80 % of the area. Except in the south of Sweden, pine and spruce are the total dominating species of trees in the forests of which spruce is the most common specie. 
The image to the above shows pine trees. Photo Hans Högman, August 2008.

The forest and timber industry has always been important to Sweden and Medelpad province (Y) had a situation similar to the Alaskan Klondike during the second half of the 1800’s. There were numerous sawmills in the Sundsvall region and people came from all over Sweden to work in the growing timber industry there. Prior to the 1850’s woodland had no significant value. Most farmers in the forest regions had large forests on their land and the primary use for the woodland was building material and firewood.
Now, when the timber industry grew fast and was in great need of timber, the sawmill tycoons went round to the farmers and tricked them to sell their "worthless" forests for nothing. Also, when the technique of making paper pulp and paper out of wood was a fact, the value of the forest rose even bigger. Sawmills first of all used pinewood while the paper mills used spruce wood. 

The pines in Sweden can reach a height of 30 meters (98 feet) and an age of 550 years. Our spruce can reach a height of 45 meters (147 feet) and an age of 400 years.
Pine was also used for making tar in the pre-industrial age.