With a barrel vault design the vectors of pressure result in a downward force on the crown while the lower portions of the arches realise a lateral force pushing outwards. As an outcome this form of design is subject to failure unless the sides are anchored or buttressed to very heavy building elements or substantial earthwork sidings. For example, at Muchalls Castle in Scotland, adjacent walls to the barrel vaulted chambers are up to thick, adding the buttressing strength needed to secure the curved design.