Interior plaster tolerances: Issue between crafts and client

Interior plaster tolerances, what is permissible and what must be tolerated? These questions are always a point of contention between craftsmen and builders. Walls must be straight, the floor level and the plaster thickness also subject to limit values.

What does the legislature say?

Manufacturing-related deviations in the construction are not inevitable. They only need to be limited by law so that the function of the structure is not affected. Possible tolerances are specified in DIN 18201 and DIN 18202.
Deviating interior plaster tolerances represent a defect that you do not have to accept. Finally, the builder may require that the thickness of his interior plaster does not affect the function, because, for example, made-to-measure built-in furniture no longer fit into the room.

What is differentiated?

The minimum requirements of interior plastering are the limit dimensions, the angular tolerances and the flatness tolerances.

Limiting Dimensions

The limit is the width and height of the plaster surface. In DIN 18202 the tolerances of the limit dimensions are given in relation to a length or width dimension.

angle tolerance

This information applies to vertical and horizontal surfaces, as well as inclinations or openings. Here, too, the specifications can be found in DIN 18202. Vertical surfaces can be easily checked with a sinker.

Flatness tolerances

They apply to surfaces of ceilings, walls or floors. The flatness can be easily checked with a leveling bar.

There are a number of other terms that can lead to confusion, at least for the layman. So that you do not lose track of a dispute with a craftsman, we would like to explain it to you.

Nominal dimension (nominal dimension)Dimensions on a construction drawing
Actual SizeDescribes the measure actually determined
Actual dimensionDifference (nominal size - actual size)
Minimum sizesmallest permissible dimension
Maximum sizelargest permissible measure
Cross-dimensionDifference (maximum dimension - nominal size) or (minimum size - nominal size)
dimensional toleranceDifference (maximum - minimum)
Flatness toleranceDeviation of an area from the intended plane
angle toleranceDeviation of an angle from the nominal angle
gaugeAuxiliary measure for actual deviation of flatness and angularity

Tips & Tricks

An assessment of tolerances in interior plaster should always be considered when wall surfaces are not vertical or uneven or the clear dimension does not allow the installation of cabinets or frames.

Artikelbild: RomanR / Shutterstock

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