Storey enclosure unit– It measure the area of external walls, floors and roof areas (effectivelyenclosing the building) and multiplying them by an appropriate weightingfactor.
Not much usedin practice and involves greater calculation.
Historicaldata are not readily available
Provides asingle rate
Take intoaccount of difference in plan shape total floor area, vertical position of thefloors, overall height, storey height, extra costs of providing usable floorareas below ground.
1. Floorareas, measured from the internal face of external walls and subject to the following weightings
basementsX 3
groundfloor X 2
firstfloor X 2,15
second floor X 2.30and add 0,15 for each successive floor
2. Roof areas are measured in its plan projection, to the extremities of eaves: roof x 1.
3. Externalwall areas, measured on the external face of the walls:
basement wall area X 2 (basement floor to ground floor level)
Aboveground wall areas X 1 (ground floor toceiling of top floor with no deduction for openings)
When this method was suggested, it aimed at overcoming the problems detected in other single-rateestimating methods, by taking into account variations in plan shape and storey height.Unfortunately, the method was never totally adopted by constructionprofessionals because it requires much more calculations than other single-ratemethods and because the rates needed cannot be directly extracted from historicaldata