Installation of new wooden benches is underway along the Vltava embankment in Prague, near Vyšehrad and at the site of the former farmers' markets — 25 sets in total, costing 5 million crowns. Soon after installation, however, visible cracks appeared in the wood, and experts say they will only get bigger.
According to Jiří Zdislav Jankovský, a master carpenter specialising in historical woodwork who has worked on timber structures at Prague Castle and Karlštejn, the cracks aren't caused by rain but by the heat of the sun, and over time they will reach almost to the core of the beam. "Personally, it doesn't bother me — wood simply cracks, and it gives it a rustic look. But the edges of the cracks need to be treated, otherwise splinters will start coming off, and someone could get one stuck in them," the expert noted.
Installation began last week and covers both single benches and two- and three-seaters, as well as two nine-seat "nest" benches. A basic module, including the base, foundation concreting and installation, costs the city roughly 72,500 crowns.
Jankovský says there would be far fewer cracks if the trees had been felled at the right time — when there is less sap in the trunk. Such timber is known as "moon wood": it is harvested during strictly defined winter periods according to the phases of the moon. It isn't sold in Czechia, but can be ordered from, for example, Austria — it costs about a third more than ordinary timber, but holds up much better outdoors.
Ondřej Protiva of a carpentry firm that also took part in restoring the burnt wooden chapel on Petřín explained that cracking in solid wood is a natural process: over time water gets into the cracks and the wood begins to rot, though in oak this process takes many years. According to him, the cracks visible now aren't a problem, and the wood itself will take on a silvery-grey tone within a few months.
The real danger isn't the water in the cracks itself, but water becoming trapped inside the wood, which can lead to fungal growth. That's why regular maintenance and treatment with wash-resistant coatings are important.
According to the city company Trade Centre Praha, the benches' lifespan will depend on climate conditions in the coming years and the degree of wear. As company representative Ondřej Šrámek explained, three special grooves have been cut into the underside of the benches to direct natural cracking toward the lower part, which isn't exposed to rain. Thanks to its high density, resin content and natural resistance to rot, oak is considered one of the most durable types of wood in Czechia — outdoors, without extra protection, it lasts 15 to 25 years. The benches come with a five-year warranty.
Visitors interviewed along the embankment were generally positive about the new benches, though many voiced doubts about their durability and were surprised by the high price. One woman said the benches looked pleasant, though she hadn't tried them out in practice yet; another visitor admitted that wooden seating would certainly be more comfortable than the old stone benches, which tend to be cold. Most people agreed that any increase in the number of benches by the river is a good thing, since previously people often had to sit directly on the ground.
Source: novinky.cz