A birch-bark roof (in Finnish: ''malkakatto'' or ''tuohikatto'') is a roof construction traditional in
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bot ...
and
Norway
Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of ...
for farmhouses and farm buildings built from
logs. The birch-bark roof was the prevailing roof type in rural Finland up until the 1860s, when it was replaced by the use of other materials such as metal sheeting and later
roofing felt
Bituminous waterproofing systems are designed to protect residential and commercial buildings. Bitumen (asphalt or coal-tar pitch) is a mixed substance made up of organic liquids that are highly sticky, viscous, and waterproof. These systems are ...
. The tradition of birch-bark roofs has been revived in recent years as a craft in connection with the restoration of old farm buildings that have been converted into
open-air museum
An open-air museum (or open air museum) is a museum that exhibits collections of buildings and artifacts out-of-doors. It is also frequently known as a museum of buildings or a folk museum.
Definition
Open air is “the unconfined atmosphereâ ...
s. The main reason for using birch bark was that when added in several layers, it acts as an efficient water- and damp-proof course. The birch trees would normally be de-barked, using a knife, during the summer.
Construction
The birch bark itself does not form the top layer of the roof. Once the main log frame of the building is constructed, the main horizontal roof poles are laid down; after this comes thin timber slats placed at right-angles to the base roof poles. On top of these then come the layers of birch-bark, each row overlapping the next. The number of layers could vary from 2 to 6 depending on the building. On top of the birch-bark layers were then placed long heavy wooden poles (usually de-barked young trees). The poles on either side of the pitched roof would be interlocked at the roof ridge. The poles were held in place at the eaves by an eaves board. The poles nearest the end gable would further be fixed with tree-root bindings. Furthermore, rocks were often placed on the roof to further add weight.
[Murtovaara. A crown forest croft. Karjalaisten Kulttuuri, Kuopio, 2008.] Alternatively, though less common, turf would be placed above the birch bark.
See also
*
Sod roof
References
External links
National Board of Antiquities
Roofs
Vernacular architecture
Woodworking
Roofing materials
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