The Forelle mountain inn is located in the middle of the Appenzell Alps, at an altitude of 1,141 metres. From a height of 950 meters, visitors can only reached the inn on foot. The courageous hikers are rewarded with a unique view over the Seealpsee lake and the Alpstein area from the garden terrace.

However, the mountain inn was showing its age, and was difficult to manage. "The garden terrace was on the ground floor, whereas the restaurant was on the first floor. Serving took place at two buffets, the food was sent to the ground floor by lift" recalls Rony Fritsche, the owner of the "Forelle". The other problem was that the old garden terrace had a gravel surface. "That was impractical. Everyday walking and catering is easier on flagging, and it is much easier to clean."

Renovation in stages

The "Forelle" was largely rebuilt in two stages from the foundation wall up. In the winter of 2016/2017 it was then the turn of the 300 m2 terrace. Rony Fritsche decided on a true-to-nature floor surface that matched the surroundings: 3 cm thick natural stone slabs made from quartzite verde.

Appenzell company Fritsche Werner AG, which was founded in the 1930s and is now run by the third generation of Werner Fritsche (no relation), was commissioned with the work. The company had already done some work on the inn. The installer was also familiar with the natural stone. They laid the natural stone slabs in 30 free lengths on crushed concrete, with joints measuring about 1 mm rather than the usual 2 mm, because client Rony Fritsche set great store on having the narrowest joints possible.

For all substrates and covering types: 3-in-1 drainage

The drainage of the terrace was a particular challenge – a drainage system for reliable drainage of the outdoor covering was urgently required, because rainwater penetrates balcony or terrace coverings via the joints and can accumulate in the construction. This leads to efflorescence, frost damage, moisture stains and weeds growing out of the joints.

The installers therefore decided to use the 16 mm thick AquaDrain PRO combined surface drainage from Gutjahr. "I have been using Gutjahr products for more than 15 years, and I have had good experiences with them," says Werner Fritsche, explaining the decision in favour of AquaDrain PRO. The system is suitable for spot bedding on crushed concrete, loose laying in gravel / chippings and point-by-point gluing with a special fixing compound.

Heavy loads

The installers were faced with special tasks when laying the floor. “The client didn't want to use a concrete base for the tables and parasols to avoid tripping hazards. Instead, we used special stainless steel rails between the natural stone slabs, in which tables and umbrellas can be firmly anchored", explains Werner Fritsche.

This resulted in particular loading of the drainage mats when the natural stone slabs were laid on the garden terrace of the mountain inn, because the stainless steel rails for the parasols and tables had to be placed onto the mats. The mats were always laid sheet by sheet, then the crushed concrete was applied and finally the natural stone was embedded. The high level of loading caused by being walked on multiple times until the stainless steel rails were at the right level, for example, was not a problem for the drainage mats.

However, high compressive strength is also required for regular "normal" use. In spring, for example, the snow on the terrace is cleared with the snow blower. The AquaDrain PRO combination drainage that was installed is ideally suited for these conditions: It was developed for installation even with higher surface loads of up to 50 kN / m2.

Precision landing for the start of the season

The work had to be carried out early in the year to be completed in time for the start of the season. And that succeeded: "It was a precision landing," says Werner Fritsche. The team benefited from the generally mild winters in 2016 and 2017. "The weather made it possible for us to drive to Seealp with snow chains almost every day, meaning that we could get the tradespeople on the construction site. We were lucky not to have to use the more expensive helicopter transports, ”says owner Rony Fritsche.

And the perfect timing paid off. “Our visitors enjoy the view from the newly designed terrace,” says a delighted Rony Fritsche. The natural stone also dries quickly, and can be cleaned every morning with a vacuum cleaner. And the new shading and arrangement of the fixed tables have also been well received. The owner of the “Forelle” is also optimistic about the performance tests for the new surface: When the drainage system has to work well in all weather conditions and the ice must not cause any damage in winter.

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