Built a rectangular outdoor pond that sits on a concrete slab, two sides are double width brick walls and the other two sides are 12 mm toughened glass panes. The glass panes measure 186 cm long and 135 cm long x 59 cm high each (maximum water depth is 53 cm at the overflow). The glass sits in aluminium channel (20 x 20 x 3 mm) which is screwed to the concrete along the bottom and to the bricks up each side. Where the panes come together in the corner there was a 1 cm gap, which I filled with clear Gold Label Pond Aquarium Sealer
. The pond was left dry for a week while the silicone cured before filling it up with fresh water. The top metal edging is only decorative, has no structural purpose.
Itís been about 3 weeks since filling the pond and today I noticed that the glass panes have moved. Both panes have pushed out at the top, with the longer pane moving enough that the silicone has peeled away from the glass at the top as seen in Fig.2 below.
Attachment 314603 Attachment 314604
Was this problem caused by the width of the silicone? Would a smaller gap between the panes have worked better?