Laastukatuse vastupidavust mõjutavad tegurid

Abstract

In the early 20th century, the traditional shingle roof became popular in the rural areas of Estonia as thatched roofs gradually fell into disuse. In the 1970s and 1980s, the shingle roof was replaced by asbestos cement, and in recent decades also by easily obtainable sheet metal roofing. In the present century, in the process of acquiring and reconditioning rural homes, shingle roofs have been rediscovered, although the tradition, which has meanwhile become almost obsolete, makes it quite difficult to find relevant practical
know-how.

In interaction with the owners of country houses, different opinions have emerged regarding the durability of the shingle roof. According to the memories of older people, in their youth shingle roofs were often repaired and were not replaced until after 40 years. On the other hand, there are oral reports of shingle roofs completed at the beginning of this century that needed to be replaced as soon as after ten years.

This article assembles oral data from roof masters, site observation of farmhouse roofs, and the experiences of homeowners, with the aim of defining the life expectancy of the shingle roof, the factors affecting this and possible techniques for its extension. To collect the data, the authors conducted interviews with homeowners and roof masters from January to April 2024. The range of questions concerned the experience of the past few decades. In the second phase of the fieldwork, in April and May 2024, 20 shingle roofs, for which data on the construction and maintenance are available from at least the last 25 years, were photographed and described, mainly in southern Estonia.

The results show that the resistance of the gable roof of the traditional simple shape and angle of inclination (at least 40 degrees or steeper), and without valley gutters, is 10 years for each layer of shingles, provided that the techniques for placing and nailing shingles are appropriate and the roof is not located under large trees, which could lead to additional risks. The advantages of three-layer roofing are best seen in buildings with an uncompleted attic. Valley gutters tend to break down significantly earlier than the rest of the roof surface, the reason being a variety of construction deficits (the valley gutter too narrow and/or open too little, with no edges bent upward). The hips being covered by shingles does not affect the condition of the roof, although the place of risk is the penetrations that require special attention. Large trees growing in the vicinity of the roof significantly shorten its life expectancy.

The study did not confirm that a wider overlay increases the durability of the roof. However, the width of the overlay must be at least 3 cm so that the nails do not damage the shingles. When choosing a tree species for the shingles, it is recommended to refrain from using a conifer on the southern side of the roof. Aspen shingles are suitable for the roof regardless of cardinal direction, but aesthetically they leave something to be desired due to warping. The ridge board of the roof needs to be replaced after 10–12 years. However, use of a ridge board is strongly recommended to prevent ridge shingles from breaking down and water from entering between them.

The shingle roof is almost maintenance-free roofing. During the roof’s lifespan, the ridge board should be replaced as needed and the gutters should not become clogged with accumulated debris. The efficiency of roof tarring cannot be confirmed based on the data acquired so far. Spot repair of the roofing, while extending its lifespan, is only applicable on smaller roofs and within a few years.

The results of the study give homeowners an idea of the life expectancy of the shingle roof and the factors that affect it. Hopefully, this new knowledge will help people make a reasoned decision in favour of installing a shingle roof.

Keywords: shingle roof, roof shingle, traditional building, natural building materials, farm architecture, ethnographic fieldwork