The Tea Pavilion, designed by architect L. I. Charlemagne—the creator of the famous southern fence of the Summer Garden—appeared in the Summer Garden in 1827, a year after its neighbor, the Coffee Pavilion. The master found a unique solution by combining the tradition of Slavic log construction with decoration in the style of Russian classicism. The Tea Pavilion, or Tea House, is an elegant structure executed in the "Russian classicism" style, a kind of subtle irony on the monumental forms of stone buildings. Although the façade embellishments of the Tea Pavilion would do credit to any architect devoted to classicism, it is built of wood, which gives it a special charm.

The only wooden pavilion in the garden consists of three parts: two enclosed rooms connected by a common roof and a Doric order with graceful columns. 

The tradition of renting the Tea Pavilion for a restaurant began at the end of the 19th century. It was revived again during the NEP era. The restaurant operated during the summer until June 22, 1941. During the war, the rooms of the Tea Pavilion housed a barracks for anti-aircraft battery soldiers, which was deployed on Mars Field.

After the war, the pavilion needed repairs. In 1949, the Executive Committee of the Leningrad Council proposed that the Trust of Canteens of the Dzerzhinsky District repair the Tea Pavilion and open a restaurant there. In the 1950s and 1960s, during the summer season, this restaurant was very popular among visitors to the Summer Garden.

The Tea Pavilion was restored from 1981 to 1984 and has looked indistinguishable from the original ever since. Despite its picturesque name, from the time of its construction until the 1980s, the pavilion’s rooms were used only as storage and utility spaces. However, in the central, open part, one could shelter from the rain during the tsarist era. Perhaps Peter himself once took refuge from a sudden summer downpour under the roof of the wooden house. Today, the Tea Pavilion is a branch of the Russian Museum. Thanks to the museum’s guardianship, there is no longer any concern about the preservation of the décor and the building itself. Moreover, it is not just part of the architectural ensemble of the Summer Garden. The Tea Pavilion is finally used for its intended purpose: here you can enjoy a cup of tea or coffee and admire paintings and sculptures by St. Petersburg artists. Few people know that any work displayed in the Tea Pavilion’s exhibition hall can be purchased. 

Source: 

https://traveloo.ru/letnij-sad-pavilon-chajnyij-domik-v-pitere.html

https://igardens.ru/tea_house/

https://spb-parki.ru/parks/letniy-sad/chaynyy-domik/