The use of thermal analysis in studying ancient mortars in English cathedrals is explained. Thermal analysis can be used to
investigate both mortar and stone in dated structures. Analysis of ancient mortars show that though recarbonated, they remain
soft, yielding to structural deformations. The use of hard (cement mortar) in modern renovation can result in micro-cracking
in the stone and subsequent chemical attack from the atmosphere. Contrary to the literature, data developed in the present
study suggests that most medieval mortars have reached a near total state of recarbonation.