Materials expand, shrink and deflect. A building without planned joints cracks in places the designer did not choose, usually across a finished surface.
Every building moves. Concrete shrinks as it dries and creeps under load, masonry expands and contracts with moisture and temperature, metal and glass respond quickly to heat, and the temperature swing on a facade in the Kingdom is large. A movement joint is a deliberate break that lets those movements happen in a controlled place. Without one, the movement still happens, and it chooses the weakest line in a finished surface.
How to test a claim like this
Judge a joint by three things. Is it continuous through every layer that needs to move, from structure to screed to tile to skirting, or does one hard layer bridge it and defeat the whole detail? Is it filled with something that can actually compress and recover, rather than with mortar or grout? And is it in a place the designer chose, which usually means at changes of geometry, at long intervals along a run, and where different materials or structures meet?
Myth 1: A joint is only needed in very long buildings.
Reality: Length matters, but so do geometry and restraint. A building with a re-entrant corner, a change of height, a change of structural system or a long wing joined to a short one needs joints at those points regardless of overall size. Restraint is what turns movement into cracking, and restraint happens at junctions, not only over distance.
How to check it yourself: Ask the designer to mark joint positions on the plan with the reason for each one, and keep that drawing.
Myth 2: Structural expansion joints and finish joints are the same thing.
Reality: A structural movement joint separates parts of the frame and runs through the whole building. A control joint in blockwork manages shrinkage of the masonry. A movement joint in a tile bed deals with the tiles, the adhesive and the screed. They are different joints solving different problems, and a building typically needs all three kinds in coordinated positions.
How to check it yourself: Check that the tiling layout and the blockwork layout both show joints, and that they line up over any structural joint.
Myth 3: A joint can be filled with mortar and covered with a cover strip.
Reality: A joint filled with a rigid material is no longer a joint. It is a line of weakness that looks like a joint and behaves like a crack. Correct filling uses a compressible backer and a sealant chosen for the expected movement, or a proprietary profile designed to take it, and the cover strip is fixed on one side only so it can slide.
How to check it yourself: Inspect what is inside the joint before the cover goes on, and confirm the sealant movement capability against the calculated movement.
Myth 4: Tiles can run continuously across a large floor.
Reality: Large tiled areas need perimeter joints at every wall and column and intermediate joints at intervals, and in areas exposed to sun and temperature change those intervals shorten. Without them, the tiles and the bed expand against a rigid edge and the tiles tent, debond or crack along a line.
How to check it yourself: Require a tiling setting out drawing showing movement joint positions before tiling starts, not after.
Myth 5: The joint can stop at the skirting.
Reality: A joint only works if it is continuous through every layer that is restrained. If the structural joint is bridged by the screed, or the tile joint is bridged by a continuous skirting or a threshold, the movement transfers across the bridge and cracks something. The detail has to be drawn through the whole build up.
How to check it yourself: Follow one joint on the drawings from the structure to the visible surface and confirm no layer crosses it.
Myth 6: Sealant lasts for the life of the building.
Reality: Sealants age under ultraviolet light, heat and repeated movement, and external joints in the Kingdom work hard. They have a service life, after which they harden, lose adhesion or split. A joint that is never inspected becomes a water path into the structure, and on a facade that is a serious defect.
How to check it yourself: Put joint inspection and resealing into the maintenance plan with the product data sheets from the handover file.
Myth 7: If no joints were provided, the building is fine because nothing has cracked yet.
Reality: Movement accumulates. Drying shrinkage of concrete continues for a long time, thermal cycling is daily and seasonal, and creep builds under sustained load. Buildings without adequate joints usually look acceptable for a period and then develop a consistent pattern of cracking that keeps returning after each repair.
How to check it yourself: If repaired cracks reopen in the same lines, treat it as a movement question rather than a decorating one.
What this changes in your decision
- Obtain a drawing showing every movement joint, structural and finish, with the reasoning behind its position.
- Verify that joints in finishes align with joints in the structure beneath them.
- Specify the joint filler and sealant by movement capability, not by appearance.
- Inspect joints before cover strips, skirtings and thresholds are installed.
- Add external sealant inspection to the maintenance schedule with an expected replacement interval.
Domira builds and supervises projects across Saudi Arabia, and this is the level of detail its site teams work at. Send the drawings or the site, and Domira will tell you what the specification has to say before anyone prices it.
Frequently Asked Questions
How far apart should movement joints be in a block wall?
Spacing depends on the block type and its shrinkage or expansion behaviour, the restraint around the wall, whether the wall is internal or external, and its exposure to temperature change. Values come from the designer and the block manufacturer guidance for the specific product. Treat any single remembered figure with caution, because the right spacing for one block type is wrong for another.
What is the difference between an expansion joint and a control joint?
An expansion joint provides room for materials or structures to grow, so it is a gap that can close. A control joint creates a deliberate line of weakness so that shrinkage cracking happens where you chose it rather than at random. They look similar on a drawing but serve opposite movements, and substituting one for the other does not work.
Why are my floor tiles lifting in the middle of a large room?
Tenting usually means the tiles and the bed have expanded with no room to move, because perimeter and intermediate movement joints were omitted or were filled with grout. Heat, underfloor services or a sunlit area make it worse. The repair involves removing tiles along the required joint lines, forming proper joints and relaying, so prevention through a setting out drawing is far cheaper.
Can a movement joint be added after a building is finished?
Joints can be retrofitted into finishes by cutting through the tiles, screed and skirting along a chosen line and installing a proper filler and profile, which is disruptive but possible. Retrofitting a structural movement joint into a completed frame is a major intervention and needs structural design. Plan joints in the design, because adding them later always costs more than drawing them.
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