What is a movement joint?

A movement joint or ‘expansion joint’ is an intentional interruption in the tile or stone surface to allow for movement in the wall or floor.

Hard flooring expands and contracts so it’s important to use a movement joint for your tiling project to prevent the tiles and grout from cracking or the tiles de-bonding. They are designed to safely absorb any heat induced expansion and the contraction of construction materials whilst also absorbing vibration and allowing movement for ground settlement.

Hairline cracks can often appear in wall tiles when no expansion joint is left in the internal corners. A common mistake is to butt the tiles up together, this causes undue stress which passes through the tiles causing micro cracks to appear in the glaze or, in the worst-case scenario, de-bond from the wall.

Movement joints can be incorporated in to the design to minimise aesthetic concerns.

All junctions between walls and floors should have a movement joint included. However, walls themselves are under continual stress and have the potential for movement, so consideration of movement joints should be made.

Consider the use of a movement joint in the following areas:

- They must be incorporated where there are any existing movement joints within the wall structure. They should align directly over the existing structure joint and be wider than the existing joint.

- At internal corners between walls to relieve stress under thermal, vibration or any other movement. This includes where internal walls meet ceilings; a suitable silicone sealant may be used.

- Where the wall tiling meets a different substrate – the tiles should be left short and a movement joint utilised. A suitable silicone sealant should be used.

- Where tiling bridges are used across different substrates a movement joint should be created at the junction.

- On large walls movement joints should be included both horizontally and vertically. Subject to the building design, joints should be incorporated every 8 linear metres.

- External wall joints (close to external angles) and all internal angles. The inclusion of a movement joint will prevent fracture and bulging of tiles with building, thermal and/or vibration movement.

- Movement joints must be incorporated at more frequent positions, should the walls be subject to significant thermal or vibration movement.

Including movement joints in floors enables the tile bed to move in unison with the individual substrates. Selection of movement joint type will depend on joint width requirement, finished floor use and movement capability.

Always consult with the manufacturer as to the most suitable joint for your application.

When tiling a floor, the use of a movement joint should be done in the following areas:

- They must be incorporated and aligned with any movement joints within the floor’s construction. The joints should be continued through the entire depth of the tiles and adhesive.

- At specified distances across a floor to create individual tile beds so no single area is greater than 100m2 without movement joints.

- Floors with underfloor heating systems should incorporate movement joints with a limited bay size of a maximum of 40m².

- At day joints or stress induced saw cuts in subfloors. The level of movement at these joints is often unknown and is usually dependant on the age of the building and whether the subfloor is fully dry. If in doubt, incorporate a movement joint.

- All perimeters and any fixed features which interrupt the floor, such as pillars or aisles, should have an allowance for movement. Sometimes this can be a suitable silicone sealant, or if underneath skirting, it may simply be a gap. In areas of high thermal change, such as conservatories, this is extremely important.

- Movement joints should be included between any underfloor heating zones to enable each to perform independently.

- Movement joints should be placed directly above any supporting walls or structural beams as they will add rigidity to the floor. The remaining floor area may be prone to a degree of flex or vibration.

- Junctions between floors and walls.

You need to select a movement joint profile that matches the thickness of your chosen tile. Apply tile adhesive (according to the manufacturer’s guidelines) and then press the movement joint into the adhesive ensuring the joint is fully embedded.

Fit your tiles so they are flush with (or slightly below) the top edge of the movement joint profile, allowing a 2mm joint around the movement joint profile, it’s important to use a flexible grout.

Perimeter joints separate the tile covering from enclosure or partition structural elements, and their function is to ensure that the movement of the tile covering is not compromised, or that the movements of these elements do not act on it. The perimeter joints must be located at all the junctions of the tile covering with construction elements that limit its movement or may generate forces in it.

A perimeter joint of at least 6mm wide should always be observed and executed and it must reach a depth of at least the decoupling or separation layer.

As the thickness of the tile plus the adhesive far exceeds the minimum width of 6mm, there should be no functional or aesthetic problem in locating the perimeter movement joint under the skirting or tile covering. Good sealing over the fill material gives a professional finish.

The covering tile or the tile that serves as a skirting or base board, must always be placed lightly over the tile flooring to avoid compromising the movement.