It is supporting (Should supporting be supported?) through an arch that transfers the pressures to the tower. The flying buttress is the support that allows cathedrals to have high vaults resulting in the maximization of the windows in the clerestory. Gothic cathedrals are very well known for their large stained glass windows. Glass cannot support the pressures of the roof so the flying buttresses helps support the weight that the glass cannot. Flying buttresses are also used to support the weight of materials added as the structure’s height increases. The original plans for Salisbury Cathedral had the buttressing system well-hidden with the side aisle roofs. When the spire and tower were added to the plan, more buttressing was necessary at the crossing (Mahner). It can be concluded that when more weight is added to the structure, additional buttressing is needed to counteract the pressures. To achieve high elevations and large clerestories, a buttressing system is very