Movement Joints

A building is subjected to different movements whose origin is either intrinsic to the building itself or induced from external sources among which the most relevant ones are:

• Maturity shrinkage of cement -based construction elements.

• Settling of structure when maturing and due to its own weight

• Live and dead loads the building is subjected to

• Hygrothermal expansion and shrinkage; i.e. due to environment humidity and temperature fluctuations

• Wind pressure and depression

• Vibrations generated either internally or externally

• Movements with a seismic origin or caused by ground instability

Foreseeing the weight and magnitude of these movements is a part of the architectural project of the building. Such a project shall anticipate stress absorption and adaptation without any damage, not even of an aesthetic nature.

Besides, installation back-grounds also present dimensional instability caused sometimes by their own immaturity [shrinkage of cement conglomerates] and always by their own nature [hygrothermal dimensional variations].

Particularly before cyclical shrinkage and expansion phenomena it shall be necessary to anticipate elements able to absorb those variations in a reversible way, as tilings, due to their rigid nature, must be adapted to the instability of the construction elements that form the underlying bedding.

This adaptation, as an antidote against instability, obligatorily requires adoption of highly deformable or elastic joints that may absorb stress caused by shear, tension and compression generated on the rigid covering.  

Movement joints are as important as the selection of the bonding material or the construction solution adopted in accordance to the background, the environmental conditions or the intended service requirements of the tiling.

Movement joints are discontinuities in the modular rigid covering that usually involve the whole section of the multilayer system and are filled with a permanently deformable material and sealed on surface with an elastic material in a length interval.

When dealing with coverings, this type of joint is referred to as movement joints in order to highlight their specificity before other denominations used in the building construction sector (expansion joints, union joints, concrete joints, control joints,…)

Movement joints are assigned the generic function of absorbing or relieving the stresses of the covering system arising from shear, compressive or tensile stresses whose origin is either internal or external to the covering system.

The contents of this documentary section may be consulted in the menu below:

• Functions, characteristics and types

• Design

• Installation

• Special joints

 

[1]   “Direct Adhered Ceramic Tile, Stone and Thin Brick Facades: Technical Design Manual”. Richard P. Goldberg. Laticrete International, Inc. (1998)