A lack of investment in maintenance and conservation has resulted
in the decay of the housing stock in Portugal, a situation exacerbated by a failure
to defi ne and implement public policies designed to encourage landlords to
preserve the constructed heritage in our cities (which is of incalculable economic
and cultural value ). When the decision is taken to intervene in a building that
shows signifi cant signs of pathology, rehabilitation work should not go ahead
until a detailed diagnostic study has been performed. The resulting report should
clearly identify problems encountered, establish their causes and suggest an
intervention method designed to ensure that certain basic requirements are met.
This article aims to contribute to the preparation of such diagnoses by presenting
the outline of a method known as Performance-based Diagnosis Applied to the
Rehabilitation of Buildings, supported by a computer application called MEXREB.
It also analyses the results of a validation study in which this methodology
was applied to a series of 39 buildings (498 individual households containing
a total of 1086 residents)

• Performance-based diagnosis applied to the rehabilitation of residential buildings Received (in revised form): 24 th July 2009 Jo ã o G. Lanzinha is Assistant Professor since 2006 at UBI – University of Beira