Braathen Dendrokronologiska Undersökningar
Lunnevägen 2, SE-46144 Trollhättan, Sweden
The tower-like ruin at Fröjel is situated about 70 m north of the church. The west wall and the upper parts of the other walls have been torn down. The basement is squared, with the outer measurements about 8x8 m and the area of about 65 square-meters. The thickness of the walls in the basement is 165 cm. Just above the level of the second floor is an outer horizontal recess in the walls of about 30 cm. The walls also have inner recesses or wall heads of about 15 cm at the three levels of the upper floors. The wall-head beams, now absent, have been put to place when the walls were built, and their inner sides were tucked into the wall about 5 cm. We count 4 storeys and we can estimate the thickness of the wall of the fourth storey to be 90 cm, (165 - 30 - 3x15 = 90). From that measurement we guess that the tower lacked an upper vault because the mass of the walls would have difficulty in withstanding the thrust of the vault. Joists which can receive the forces of thrust have not been much used in vault construction on Gotland. In the outer sides of the walls and at the level of about the middle of the second storey are holes for scaffolding poles with support of braces. From that we can conclude that the walls up to the third floor were built from both sides. Near the crest of the ruin are a few bricks of burnt clay in the wall. If they were put to the wall when it was erected the building cannot be older than when the first burnt bricks came into use on Gotland. Bricks are found in 13th century churches on Gotland.
Remains of a beam, found among the fallen down debris could not be dated mainly because of too few annual rings.