Stone Expansion Joints

Expansion joints maintain the success and longevity of tile assemblies. Tile assemblies that face direct sunlight and harsh weather conditions undergo expansion and contraction that decreases their shelf life due to cracks at random places.

Consequently, installing expansion joints in tile assemblies is critical to avoid pop-ups in the floor’s centre. Commercially and residentially, tiles tenting are standard, and the only way to prevent it is by installing the stone expansion joints. Plus, the roads with high-intensity traffic mostly employ expansion joints to reduce damage due to climate and heavy loads.

Tiles and Stones Expansion joints

All tiles and stone assemblies in buildings, bridges, and railways track move due to thermal expansion, shrinkage, freezing, moisture, or other structural movements. Tile and stone installations confront all these threats. Therefore to ensure long-lasting instalment and protection against the effects of shrinking and expansion, architects uses a movement joint and select the material that seals these junctions properly. 

Role of Expansion joints in construction

Various articulations in the construction materials are movement joints, commonly known as control joints with multiple categories. A movement joint contain a proper sealant for the anticipated application and are often called soft hinges. Moreover, the movement joints allow the material to expand without cracking. 

Movement joints between different tile materials allow expansion and shrinking without any limitation. Moreover, they prevent tiles through efficient spacing, for instance, the separations in the concrete sidewalk. If junctions are missing between them, the tiles will crack either by shrinking associated with cold environment and expanding due to sunlight. 

Additionally, the rising temperatures cause the expansion of materials, and lower temperatures cause freezing. Still, both expansion and shrinking could occur due to moisture freezes as the temperature drop in wet freezing conditions. 

Many structural deformations arise due to several processes occurring in the ground that can lead to movements. Stresses, contractions, and expansion may occur without environmental factors because each material has a coefficient of movement properties. 

Material expansion may lead to different problems because each material has a varying coefficient of movement that could affect adjacent materials. Architects design the movement joint in such a way that they can isolate different materials without affecting the adjacent materials. 

Failure in installing tiles, ceramics, stones, and glass occurs because of the movement joints’ improper instalment. In most situations. Failures could be avoided by adequately installing the movement joints to allow the materials to expand and contract according to the climatic condition and ensure the construction’s longevity and strength. 

Types of Expansion Joints

An expansion or movement joints are structural junctions that move vertically and are installed in concrete substrates to separate one portion of the slab from the adjacent ones. In mortar beds, engineers install them to separate one bed from the other. Proper design of a movement joint in mortar depends on the assembly configuration or substrate type of tile and stones. 

A cold hinge is also a kind of expansion joint in which two neighbouring concrete slabs are present at an alternate time. They are the points where cracks form most of the time, called movement joint. Another type of joint is construction, or contraction articulations called saw cut concrete joints. In this type, the concrete is saw-cut at a specific spot that makes a weak point for crack. 

Perimeter movement joint are the most common that every tile assembly was must possess. In this kind, a tile placed adjacent to the wall has a gap between the tile and wall. In the perimeter joint, the gap is vacant, without any sealant present. It is roofed with the help of baseboards everywhere in the room. 

In hardwood floors, a small gap is left between the tiles and the hardwood filled with caulking. This filler is visible, and it ruins the aesthetic value that is why it is a bad idea. Plus, it fills the gaps and provides no surface for movements due to expansion and shrinking. 

The field expansion joint has a filling of some adhesive material such as sealant or caulking agent. The silence matches the colour of the grout, and it becomes invisible. Field junctions are extended from wall to wall to become effective. These hinges are found at the doorways, keeping them as short as possible.

Where Should Expansion Joints Be Placed?

Engineers and specialists favour installing expansion and contraction joints with every tile to increase its shelf life. If the rooms are small, then installing tiles requires an expansion joint only at the room’s perimeter that hides under the baseboard. In large areas, expansion joints are important and visible too.

It is not a convention to install the expansion joints at specific sites, and their frequency is variable. The number of expansion joints depends on some conditions. In places where climatic conditions are harsh, such as rainfalls and sunlight, falls directly require more expansion joints. More movement joint prevent the tearing up of tiles due to stress due to expansion and contraction. 

Requirements For Floor Tile Expansion Joint

People involved in the installation of tiles on floors are sometimes unaware of the fact that they move too. If the movement factor is out of consideration, it will affect the life of tiles and become expensive for the owners of offices or buildings. 

A tile and stone installer must know about the expansion joints so that he can install it perfectly. Though it is not the tiles installer’s responsibility, it is the responsibility of architects and engineers. Even then, the person hired must know about the phenomena of shrinking and expansion in tiles. 

There are some set points for installing the floor tile expansion joints:

  • The width of the joint is four times that of expected movement. 
  • The backup design should be compressible
  • The backup should be round without any bond to the sealant.
  • The filling, if done with sealant then the width should be one-half of the width of movement joint. 

Movement Joints Spacing Considerations

Several things require consideration while determining the spacing for the expansion joints. The following list mentions them all.

  • Refraction and vibrations in the substrate arise due to suspension in slabs.
  • Earthquake activity in a specific area
  • Change in planes and angles of tiles.
  • Types of tiles, stone, concrete, or glass 
  • Compression of the tiles.

Sealant and Caulking Considerations

The expansion joints’ design is vital to a great deal, but the proper sealant ensures such movement joints’ success. A standard sealant is required to fill the junctions, and the widely used sealants are urethanes, polysulfide materials, and high-quality silicones. They are weather-resistant, have high elongation properties, and high adhesion capability. They come with a warranty for decades.

Some installers use acrylic, latex, and other siliconized sealants because they are easier to install in tiled area. Still, they have no warranty, and they are not long-lasting as compared to standard sealants. Every sealant has different physical properties and performance. Their applications also differ this way. Each of them has its specific type, class, and grade precisely according to their application. 

Soft sealants are not suitable for the floor tiles expansion joint because the heels can penetrate in them. Different sealants have fire and acoustic ratings for different applications. The submerged applications require special sealants. Some of them are not compatible with the stone naturally and cause the stone to mark out.  So proper sealant selection is essential for the required application. 

Sealant Requirements 

Though the movement joint’s design must be proper, it is also necessary to choose the proper sealant to install successfully. A sealant usually requires a two-point contract that can only adhere to the two surfaces of tiles. It should not adhere to the bottom of the joint material because expansion will not occur in this case. A polyethene tape or foam inserts beneath the joint width to prevent sealant from adhering to the bottom. 

Application of sealant requires proper width and thickness. To gain maximum performance, the sealant should not be applied too thick or thin. It must be 6.6 mm thick, and its width to depth ratio may be 2:1. In adhered tiles nonmoving intersections, the companies prefer 3mm application, but the movement joints should be 6.4 mm standard. 

Backing Considerations

In the backing below the sealants, the joint filling prevents the moisture collection’s voids. Cell foam is the best choice for this, but some sealants entail open cells to manage the off-gassing. 6.4 mm mosaics are best for thin tiles, while in the case of porcelain tile panels, the width requirement is 3mm. Bond-breaking tape is difficult to install, so it is okay to leave it out. 

Sometimes prefabricated movement joints made of metal are used. They have plastic inserts that adhere beneath the tiles. Typically, they are L-shaped. It is convenient to install. After that, the joint requires filling with a sealant. The plastic inserts are easily replaceable, and the metal angles are bonded to substrates and abstain movement. But to provide longevity to the tiles assembly, the installation should allow movements.  

Sidestepping Aesthetic Problems

The movement joints are often unconstructed because owners say they ruin the esthetic look, especially marble expansion joints. The absence of the movement joint causes failures that are uglier than these. When the architects and engineers give proper time to designing, they can manipulate features to save the place’s aesthetic value.

Silicon sealants have a broad range of colours that can make a perfect match to fill the tiles and stone hinges. The colour of the resulting sealant can easily match the colour of the tile, and it would maintain the aesthetic look of the place. In staggered joins, the engineers prefer staggered grout junctions that make the sealant less prominent. Also, the intersections are not noticeable if the filling goes correctly with the features of the installation. 

How to Install Expansion Joints in Tile Floors?

After getting deep insight into the movement joint, one can install an expansion joint easily. Firstly, tape off both the tiles’ sides because the sealant or caulking can create a mess. The tape will keep it all set. Then take a backing rod and stuff the joint carefully. It is generally a string-type product that is somehow insulation-type material. The thickness of the backing rod ¼ inch is perfect, but bigger sizes are also available. 

However, using a backer rod is a good option because it optimizes the performance and keeps things in place. Caulking or sealing requires pure silicone or urethane. Silicones are best because they are available in many colours and shades, while urethane has limited colours. Apply sealant to the joint and wipe out the excess with a paper towel. Remove the tape and dispose of it properly. 

Add a few thinner drops such as mineral spirit, denatured alcohol, or paint thinner to eradicate unevenness due to the tap removal.  Also, make sure to clean the details with a paper towel. 

Sidestepping Aesthetic Problems

Tile flung on the floor sometimes cracks because of an insufficient number of expansion joints installing. If concrete is present as a base, the tiles face compression that causes the tile to break. This phenomenon refers to the tent in expansion joints. The tiles’ tent depends on the forces above the tile layer that may be temperature or pressure, the withstanding power of this set, and the rate at which the concrete layer shrinks below the tiles. 

Poor bonding causes the tile to the tent because the grout compression is poor, and as a result, the tile loses its bond. Type of tile plays a vital role in the tenting process because if the thinset has strong bonding to porcelain, then the tent rate is lower. Sometimes the thin-set and grout are assembled stronger than the tile.  

However, each installation should have stronger bonding and allow expansion and shrinking movements. Movements do not allow shear forces and prevent the tile from tinting because they remain well adhered. The reduced tint increases the longevity of the tile assembly.