Sampling Of Accepted Dimensional Tolerances In Us Construction


Squareness of residential foundation W in 20'

Plumbness of wall ±W in 10' Variation of wall from building line in plan ± 1"

Variation in wall thickness — M", +YS

Plumbness of column W" in 10', but not

4. Deflections and creep in beams and slabs complicate the picture. It is unwise to detail prefabricated partition or cladding panels to fit closely under beams or slabs. Even a generous sealant joint between the two is often insufficient to accommodate normal deflections. It is better to locate cladding panels entirely outside the structure and to mount them in such a way that they are isolated as much as possible from deflections and creep in the frame. There must be good communication among the detailer, the structural engineer, and the cladding manufacturer to limit spandrel beam deflections and to provide sufficient horizontal movement joints in the cladding. Non-loadbearing partitions should be separated from the floor structure above by sealant beads or gaskets whose height is determined by the structural engineer (see Structure/ Enclosure Joint, pp. 84, 85).

5. Where dimensional tolerances accumulate from a set of assembled components, each with its own individual tolerance, an overall tolerance can be calculated by taking the square root of the sum of the squares of the individual tolerances. If, for example, a bay of a building is clad with three precast concrete panels, each panel having a tolerance of ±W\ and a window unit with a tolerance of ±1/16", the overall dimensional tolerance for one bay is figured as follows:

Overall tolerance

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