An expansion joint must not be confused with control joint. The difference is that a control joint is a break or a cut in either the vertical or horizontal surface to prevent tensile stress from developing across that joint. Control joints are generally filled with sand, mortar, grout or silicone.
An expansion joint is a specific movement profile that bridges the gap between 2 meeting surfaces to provide a suppression joint that prevents surface compression cracking and bridge movement gaps.
Expansion joints are designed to accommodate thermal, moisture and surface, substrate or foundation movement variations such as expansion, contraction, floating and many other causes. Hidden expansion profiles and surface expansion profiles are engineered explicitly for the complex range of gap size, movement size, direction, and load/use type.
Surface expansion profiles are visible and must be both correctly suited to traffic use and visually appealing. Then consideration must also be made to determine if the expansion joint should accommodate lateral movement, horizontal movement, vertical movement, or combinations.
Unfortunately, all too often, the wrong expansion joint is specified or used for the incorrect application, which can and has resulted in massive rectification costs. Two main factors determine the effectiveness of expansion joints.
- Expansion Joint Selection
- Expansion Joint Installation
Below is an example of both factors resulting in failure
Surface inspection clearly shows joint expansion failure. The subsurface reveals incorrect installation of the expansion joint.
Below is the positive result when the correct expansion joint is selected and correct expansion joint installation procedures are followed.
It is obvious the importance of joint expansion selection and the methodology required for its effective installation. Expansion joints are specified by architects, engineers and designers or industry body specialists.
The fantastic variety of simple to complex expansion joints is mind-boggling and unquestionably a specialised science.
Concrete structures are only as watertight as the Waterstop Systems that join them. In most concrete structures and elements, a particular type of joint (construction, contraction, control, expansion or isolation) will be designed in them for a number of varied structural design reasons, and due to this joint, it may need to be water stopped as the structure is water retaining or water excluding.
Waterstop systems are an essential part of most projects, and they should be required for all those working on them. There are many types of Waterstop Systems to be considered for use, and a particular type may need to be used for the joint that has to be water stopped.
We have a wide and varied number of Waterstop Systems available for use for many different types of construction segments.
Contact us if assistance is required in choosing the correct type of Waterstop System for your structures joints.
Joint Sealants & Joint Seals
There are many different types of joints in a structure, and it is important to keep them free-flowing so that water can’t get trapped inside. If this should happen, then you’ll need Joint Sealant – which comes with all new construction projects. At the same time, they must withstand the associated movements of the joint and the loading pressures being applied.
The Joint Sealant or Joint Seal may also need to withstand exposure to UV, withstand submersion in water or saltwater, or even have resistance to fire or specific chemical or hydrocarbon solutions.
We have many different types of Joint Sealants and Joint Seals available for use, and depending upon the type of joint designed, the kind of structure and the type of exposure that they could be subject to determine the class to be used.
Contact us if assistance is required in choosing the correct type of Joint Sealant or Joint Seal for your structures joints.