Joisted Masonry Construction (ISO)
Definition
Joisted Masonry Construction (ISO) — one of six building construction categories established by Insurance Services
Office, Inc. (ISO), in its Commercial Lines Manual (CLM) for purposes
of developing rates for insuring commercial property, based on susceptibility
to damage by fire. The CLM description of joisted masonry
construction, followed by the associated ISO construction code, is exterior
walls of masonry material (adobe, brick, concrete, gypsum block, hollow
concrete block, stone, tile, or similar materials), with combustible floor and
roof (Construction Code 2). The construction code indicates the ranking of this
building construction category within the six categories, with 1 as the least
fire-resistive and 6 as the most fire-resistive.