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Movement Joints

Movement Joints

When it comes to constructing sturdy walls, it’s easy to focus solely on the bricks and mortar, but there’s a silent hero often overlooked in the process – soft joints. These flexible seams play a vital role in ensuring the durability and integrity of a wall structure. Their absence can lead to cracking and water infiltration, causing significant damage.

Soft joints, also known as movement joints or control joints, are intentional gaps incorporated into a wall assembly. Unlike rigid connections, these joints allow for slight movement or expansion and contraction of materials in response to temperature changes, settling, or other environmental factors. Essentially, they act as stress relievers, preventing the buildup of pressure that can lead to cracks.

 

How? 

Imagine a scenario where a wall lacks soft joints. As the temperature fluctuates or the building settles over time, the rigid structure becomes vulnerable to stress. Without the flexibility offered by soft joints, the pressure accumulates, eventually causing cracks to form along weak points in the wall. These cracks not only compromise the aesthetic appeal of the structure but also pave the way for water infiltration.

Water infiltration poses a multitude of problems, ranging from cosmetic issues to structural damage. Once cracks breach the protective barrier of a wall, moisture can seep in, leading to dampness, mold growth, and even structural degradation. In addition to compromising the stability of the wall, water infiltration can also affect the indoor air quality, posing health risks to occupants.

By strategically placing soft joints at predetermined intervals, builders can accommodate the natural movement of materials without compromising the integrity of the structure. Whether it’s a concrete wall, masonry construction, or a combination of materials, soft joints provide the necessary flexibility to withstand environmental stresses.

 

Furthermore, soft joints serve as a proactive measure against potential damage. By pre-emptively addressing the need for movement accommodation, builders can minimize the likelihood of cracks forming in the first place. This not only enhances the longevity of the wall but also reduces maintenance costs and headaches for homeowners down the line.

Unfortunately in South Africa, many shortcuts are taken when it comes to the creation of joints and maintenance of joints in refurb projects. During redecoration projects, we usually find one of three scenarios. 

  1. The Joint is missing completely and cracks have occurred where the joint should be. In this instance, we can cut through the plaster to find either where the split was made between materials or where the material is creating a natural crack. We can create a joint by opening up the substrate inserting a foam backing cord if possible and fill with a hybrid joint filling sealer.

 

  1. The Joint is partially created, and has been made with a receded line in the plaster known as a rule joint this is not ideal for external exposure as this joint directs the crack to form along the receded plaster line but the crack that forms allows water ingress into the structure. If the joint is external we usually open up the Joint to identify if the joint was created in the correct place. We then assess if it is possible to insert a foam backing cord and then seal the seam with a flexible hybrid sealant.

 

  1. The Joint has been partially patched by a previous contractor this usually takes place when a contractor is inexperienced, the contracting team is not supervised or no quality inspections have been conducted or the contractor has purposefully taken short cuts. In this case, we would have to re-open the joint to the original joint seam or the substrate split, Identify if the joint was correctly placed, and install a backing cord if possible. We then fill the joint with a hybrid flexible sealer.

 

Flexible Joints should never be closed with a plaster or skim coat. They need to be located in the correct place or they become redundant. The flexibility of the sealer reduces over 10 years due to exposure to the elements. Once this happens the joint can usually be cleaned out and resealed with a new application of sealant. 

 

In conclusion, the importance of soft joints in wall construction cannot be overstated. These seemingly small details play a significant role in preserving the structural integrity and functionality of a building. By incorporating soft joints, builders can mitigate the risk of cracks and water infiltration, ensuring that walls remain resilient and watertight for years to come. So, the next time you admire a well-constructed wall, remember to appreciate the unsung hero – the soft joint.