Concrete Bags and a Wooden Bond Beam

For the circular hall we poured a reinforced concrete bond beam on top of the walls. Its the strongest method and allowed us to add connection points for the 24 columns that sat on top. For the outer wall this seemed like overkill. The function of the bond beam firstly to tie the walls together, and secondly to allow for connection points to stop the roof lifting off. We decided that the outer wall is strong enough thanks to the curved wall and additional buttressing, so we just needed a roof connection. Multiple 5m wooden beams were attached to the top of the wall using concrete foundation bags (pictured), two bags with reinforcement between and rebar driven down into the wall. The roof beams will be bolted down to this wooden beam.