The History of Swedish X-joint Log

Houses

Introduction

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 image shows Delso farmstead (Delsbogården), Skansen Open-Air Museum. Photo Hans Högman 2008.

Terminology

The Swedish term “knuttimmerhus” is normally translated to X-joint log house or cross-joint log house. The technique is called ”knuttimring” which 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”.

History

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 time frame 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

Sealing

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) 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 spiece. The image to the right 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.

Building Technique

When building log houses, logs of equal thickness are desired and the top end has to be thick enough to be able to cut out the X-joints, the notches. It was important to use full length logs for the bottom row, above windows and doors and for the top row of the walls since they were the logs that held the house together. The logs for the bottom row (the sill) were normally a bit thicker than the other logs. In the openings like doors and windows the crosscut end of the logs were strengthened with a stabilizing piece of board, a so- called “gåt”, which was inserted in a cut in the crosscut end of the logs. By constructing buildings with horizontally laid logs one could control the movements of the wood and if the x-joint log house was properly built, the only consequence of the log shrinking was that the wall sank a bit. In constructions with vertical logs, the shrinking often resulted in chinks between the logs in the walls. In order to get the right balance in the X-joint buildings, the logs were laid top end against butt end, for example in the first row the top end was to the left and in the second row to the right. In X-joint log houses you use corner joints both in corners as well as at partition walls. This made the log houses very stable. An effect of that was that the walls could carry a heavy and a well insulated roof. If you had to lengthen a log this was done at a partition wall with an X-joint. The cross joints were designed differently throughout the centuries. Beside that there were also regional differences. It has been estimated that there has been about 250 to 300 different variants of cross joints in Sweden. Normally the cross joint on the upper side of a log had a diagonally or vertical cut notch with a carved threshold called “bettna”. The log on the upper row had a similar groove where the “bettna” fitted in. Since X-joint heads have varied thought-out times, an approximate dating of X-joint buildings can be made by looking at the heads. The image below shows a construction of a multistory X-joint log house in the1670's.

Roofing

Thatched roofs have been common roofing on utility buildings in the grain producing flat lands of central and southern Sweden since the Middle Ages. In the southern-most provinces they even used thatched roofs on the dwelling houses. In central and southern Sweden (beside Skåne) turf roofing  dominated on the dwelling houses while thatched roofs were used for utility buildings, cowsheds etc. The turf was placed on top of a layer of birch-bark. In Norrland region, northern half of Sweden, they first of all used wooden roofing. The top plate was a rough plank or heavy pole and then poles or planks were laid vertically, side by side, up from the plate to the top ridge pole and the entire surface was covered with a sealing layer of birch bark. Other poles, split in half,  were then laid on top to hold down the bark. The cheaper and lighter wooden shingle roofing (shake) later replaced wooden roofs. Shingled roofs became common when sawmills began producing shingle for sale. Tile roofing became common during the 19th century. Prior to the 1800’s tile roofing was only used on exclusive buildings like manors etc but during the second half of the 19th century tiling also became common on cottages and smaller houses. In Gotland stones chips were a common roofing material.

Windows

The old Swedish word for window, as well as the ancient common Nordic language Norse, was “vindöga” (wind eye) which originally meant a smaller opening, loophole/aperture, with a folding or sliding wooden shutter without any glass. Larger apertures were usually covered with a translucent cloth of linen or an ox bladder. Glazed windows were uncommon in town homes during the Middle Age and in the countryside until the 18th century. In the beginning of the 18th century the glass making improved and it became possible to make larger panes of glass and the use of glazed windows increased. During the 1700’s Swedish glass panes had a greenish color tone and in the 1800’s a more light green tone. However, during the 1850’s the color tone of window glass became the clear tone of today. The window sash was introduced during the last part of the 1800’s.

The Farmstead

Unlike the log cabins of the US frontier, where the log cabins most often were smaller temporary dwellings with only one room, the Swedish log houses were purpose built permanent dwellings. Swedish log houses were also much larger than the US log cabins and had several rooms. During the 18th century and especially during the 19th century the Swedish farmstead log house dwellings most often were two- story buildings with a richly decorated exterior. US log cabins had the fireplace and chimney at the gable while the Swedish log houses had fireplace and chimney inside the house, normally placed in the kitchen. Adjacent rooms shared the same chimney and larger log houses could have two chimneys. The image to the right shows the entrence of the dwelling house at Delsbo farmstead, Hälsningland (X). Photo, Hans Högman, August 2008, Skansen. In the northern half of Sweden, i.e. Dalarna and the Norrland region, the farmsteads were build around a farmyard. The farmstead buildings were surrounded by an open farmyard with a gateway (portlider) out of the farmyard. Every building, including the dwelling house was a log house. All buildings like the dwelling house, cowshed, stable, sheds etc were placed close together. The closed farmyard shut out both farmstead animals as well as wild animals and gave some privacy. Special fences called “gärdgård” were used to keep farm animals away from arable land and meadows, not to enclose them. The farm animals moved around freely grazing and could go any place that wasn’t fenced. A “gärdsgård” is a wooden round pole fence typical for Sweden. It is usually made of non-decorticated and non-split young spruces or of tops of spruce trees. The fence consists of upright poles in pairs held together with linings of osier. Between the upright poles there are diagonally laid round poles, with the top end facing the ground. The length of the diagonal poles was about 4 meters (13 feet). The fence is usually 1.5 to 2 meters tall (5 to 6.5 feet). The image to the left shows a typical Swedish gärdsgård. Photo Hans Högman, July 2008. Since the buildings, including the roof, was made of combustible material there was always risk of fire. In the old days farms were self-subsistent households and every building had its special use. Work that needed fire was done in special log cabins located a bit away from the actual farmyard buildings in order to diminish the risk of fire. Examples of those cabins were the smithy, bakery house, laundry house and smokehouse (used to smoke food or dry flax, grain and hops). Also storage cabins (härbre) and barns were outside the actual farmyard In the eastern parts of central Sweden the farmyards had a more rectangular shape than in northern Sweden and the buildings were wider apart. Here they kept the cowshed a bit further away from the dwelling house. Nevertheless the buildings formed a farmyard with a gateway. In these parts there were many manors and at the manors the buildings for animals (like the cowshed) were located far away from the main building and that has probably influenced the farmsteads in these parts to do the same. In the western parts of central Sweden the buildings of the farmsteads were more spread out than the rest of Sweden. A variant of the farmsteads in east central Sweden was the so-called gothic farmstead (götiska gården) where the dwelling house was separated from the cowshed with a fence or was located at the other side of the road. The farmsteads in the south most part of Sweden, first of all Skåne and Halland, are known for its closed square-shaped farmyard, however with a more complete enclosure than in Norrland. The houses down here weren’t built like the traditional X- joint log houses in the rest of Sweden but with a technique called “korsvirkeshus” in Swedish (half- timbered houses with clay daubed walls). During the second half of the 1800’s the way buildings were located at farmsteads changed quite radically. The enclosed farmyards were broken up in Norrland as well as in Skåne. In northern Sweden they abandoned the system with the multi-purpose log cabins like the smithy, smokehouse etc due to a reduced use of the self-subsistent house holding. With supplies that had required earlier farm production now available in stores, the need for special cabins more or less ceased to exist.

Drawings of Different Types of Farmyard

Formations

Hässja - Hay Drying Racks

Special hay-drying racks, called “hässja”, were used to dry cut grass etc into hay. They were raised in the meadows. Also the work of piling hay on the drying racks was called to “hässja”. There were special drying racks for barley, which were used to dry the barley prior to threshing. These racks were larger than the ones used for hay and called “kornhässja”. The hay-drying racks were constructed in different ways in different parts of Sweden. A common type was the so-called “stånghässja” with horizontal laid poles. Very tall racks were used in Norrland region called “storhässja” (grand hässja). The image to the right shows a hässja from central Sweden. Photo Hans Högman, July 2008.

Three Common Swedish Corner

Styles – Notches

• Rännknut - Saddle notch(?) • Dubbelhaksknut • Laxknut - Dovetail notch

Rännknut

The “rännknut” ("ränn" X-joint) is the simplest of the X-joints and in Sweden the earliest one known. This X-joint was used with round logs. The construction of this X-joint varies but what they all have in common is that the bevelling of the upper log is placed in the notch (“saddle”) of the log below which had slanting walls. “Rännknuten” was very common in the northern parts of Sweden. However, after the 18th century it was only used on utility buildings or simpler log buildings. In the oldest variants of “rännknuten”, the X-joint only had a half round hollowness at the upper side of the log (överhaksknut). This X-joint was later developed into the “rännknut”. The "rännknut" was probably the type of X-joint the Swedish settlers brought to America in the 17th century (the New Sweden Colony), which was later named Swedish Saddle Notch in the US?

Dubbelhaksknut

The X-joint was developed further at the end of the Middle Age and got a carved threshold (“bettna”) in the middle of the notch, a so-called “dubbelhaksknut” (double notch X-joint) or at the side of the notch – a “enkelhaksknut” (single notch X-joint). This resulted in a tighter and more stable construction. This X-joint, the “dubbelhaksknut”, became the most common X-joint during the 18th century. Hewing of the exterior side of the logs began in the 17th century. Also the X-joint heads were vertically hewed. The “dubbelhaksknut” was in other words used both with round logs as well with hewed logs. When the logs were hewed they were turned upside down to avoid waterlogged gashes.

Laxknut - Dovetail Notch

At the end of the 19th century the older X-joints with protuberant X-joint heads were replaced with X-joints with smooth corner joints. The most common one of those X-joints was the “laxknut” – the dovetail notch.

Sketch of a Cross Joint

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Related Links

• Photo Gallery Log Houses

Source References

1. Nationalencyklopedin 2. Byggnadsvård, Skansen 3. Knuttimring i Norden, 1986, Red. Göran Rosander, Dalarnas Museum 4. Uppländsk knuttimring, särtryck ur Uppländsk bygd, 1940, Nils Ålenius. 5. Timringstekniker, Högskolan Dalarna 6. C-Uppsats, "Knuttimring" av Lars Hedman, 2003, Institutionen för arkeologi och antik historia, Uppsala universitet 7. De gamla hantverken - redskap och metoder från självhushållningen tid, John Seymour, 1984. [Eng. originalets titel: The Forgotten Arts]. 8. Byggnadsvård för landbygden - Timmerhusens uppbyggnad, Länsstyrelsen, Västerbotten 9. Timringskonsten en tusenårig tradition, Länsstyrelsen Dalarna 10. Hantverksbladet, Timmerväggar, Skellefteå Museum Top of page