EXPANSION JOINTS | Schluter DITRA Installation Handbook & TCNA EJ171

SCHLUTER DITRA INSTALLATION HANDBOOK
MOVEMENT JOINTS | Pages 15-17 

DISCUSSION

Movement joints are an integral part of any tile assembly. The various components of a tile

assembly (tile, mortar, substrate, etc.) have unique physical characteristics that affect

their behavior. Specifically, these components will expand and contract at different

rates, according to each component’s intrinsic physical properties, with changes

in moisture, temperature, and loading (both dead and live loads). This differential

expansion/contraction of attached components results in internal stresses.

Furthermore, structures that restrain overall expansion of the tile field (walls, columns,

etc.) cause stress buildup within the system. If the aforementioned movements

are not accommodated through the use of movement joints in the tile field and at

restraining structures, the resulting stresses can cause cracking of the grout and tile

and delamination of the tile from the substrate. Thus, movement joints are an essential

component of any durable tile assembly.

SOLUTIONS

Movement joints must be incorporated within the tile field, at doorsills, and at transitions

to walls and other restraining structures to allow movement of the assembly and prevent

stresses that can damage the system. Schluter®-Systems’ prefabricated movement joint

profiles protect tile edges and prevent sound bridges and surface water penetration,

resulting in a permanent, maintenance-free installation. The family of Schluter®-DILEX

prefabricated movement profiles includes a variety of shapes, sizes, and materials to suit

different applications. Please see Schluter®-Systems’ Illustrated Price List and visit www.

schluter.com for more detailed information on DILEX movement profiles.

TECHNICAL NOTES

The Tile Council of North America (TCNA) and the Terrazzo, Tile, and Marble Association

of Canada (TTMAC) provide guidelines (EJ171 and 301MJ, respectively) for the

placement and construction of movement joints in and around the tile field. Schluter®-

Systems accepts these guidelines. However, given the increased use of larger tiles,

smaller grout joints, and lighter building materials, which are more susceptible to

movement, Schluter®-Systems recommends that movement joints within the tile field be

placed at more frequent intervals, as indicated below.

Guidelines for the placement of movement joints:

• Field size not to exceed 400 sq/ft
• Interior applications: 16' - 20' in each direction
• Interior areas exposed to direct sunlight, moisture or heated floors: 12' in each direction
• Place around the perimeter of any size floor and/or against all restraining surfaces
• Fields should be as square as possible. The ratio between length and width should not exceed 1:1.5

PERIMETER JOINTS

Perimeter joints are provided at the outer edges of any tile installation to accommodate

movements attributable to changes in moisture, temperature, and loading. See figures

1, 2, and 3.

If Schluter®-DILEX corner movement profiles will not be used, Schluter®-Systems

recommends the use of BEKOTEC-BRS/-BRSK edge strip or sill seal (a compressible

polyethylene gasket used to seal the gap between foundations and sill plates) as a

quality control measure when providing perimeter movement joints. The edge strip/

sill seal band is placed against perimeter structures before any component of the

tile assembly is installed, (e.g., Schluter®-DITRA/-PS, Schluter®-DITRA-XL, additional

underlayments including self-leveling materials, mortar beds, etc. See figures 2 and 3).

After the tile is installed and grouted, any excess edge strip/sill seal material is cut away,

leaving a movement joint with uniform width that is void of any mortar, grout, or other

restraining materials that would render the joint ineffectual.

SURFACE JOINTS

Surface joints must be placed within the tiled surface regardless of substrate conditions.

They provide for stress relief from movements in the tile field due to thermal and moisture

expansion/contraction and loading. See figure 4.

EXPANSION JOINTS

Expansion joints permit both horizontal and vertical differential movements attributable

to thermal and moisture expansion/contraction by providing a complete separation

for the full depth of the slab to allow for free movement between adjoining parts of a

structure or abutting surfaces. They are typically placed at columns, walls, and any other

restraining surfaces. Expansion joints must be continued through the tile covering.

DITRA/-PS and DITRA-XL are separated at expansion joints and the joint is continued

through the tile covering using DILEX surface movement profiles. When DITRA/-PS

and DITRA-XL are used as waterproofing, the abutted sections must be covered with

Schluter®-KERDI-FLEX or Schluter®-KERDI-BAND.

COLD JOINTS

Cold (construction) joints occur where two successive placements of concrete meet.

True cold joints bond the new concrete to the old and do not allow movement. However,

it takes extra care to accomplish this, so they are usually designed to act as expansion

or control/contraction joints. Cold joints are treated in the same manner as expansion

joints. See above.

CONTROL/CONTRACTION JOINTS

Control/contraction joints are designed to induce controlled cracking caused by

drying and chemical shrinkage at preselected locations. They are typically formed by

saw cutting, tooling, or through the use of inserts. DITRA/-PS and DITRA-XL are not

separated at control/contraction joints; however, surface movement joints must be

provided in the tile covering in accordance with the aforementioned guidelines. See also

Surface Joints.

Soft joints are not required directly above concrete slab, when using DITRA/-PS or

DITRA-XL membrane.

STRUCTURAL or SEISMIC JOINTS

Regarding structural and seismic expansion joints, please contact Schluter®-Systems at

800-472-4588 (USA) or 800-667-8746 (Canada) for proper installation guidelines.

NOTE REGARDING RESIDENTIAL APPLICATIONS

Due to the increased popularity of continuous tile installations (i.e., tile continuing

from room to room on a given floor), movement joints have become both increasingly

important and increasingly difficult to provide. For instance, consider the residential

installation shown in Figure 5. It is almost certain that the homeowner will resist the idea

of placing movement joints across any of the rooms shown in the figure, despite TCNA,

TTMAC, and Schluter®-Systems guidelines. However, the need for movement joints in

this installation is undeniable, given the extended size of the field. The question then

becomes, “How does one provide the movement joints necessary to ensure a durable

installation without compromising the aesthetic qualities of the continuous tile field?”

The easiest way to accomplish this goal is to begin by providing movement joints at the

perimeter of the installation. Perimeter joints are absolutely necessary and do not interrupt

the tile field. The next step would be to place movement joints at the thresholds between

rooms or where a tiled hallway meets a larger tiled room. These locations are relatively

inconspicuous and the lines formed by the movement joints are logical in that they

reflect the natural perimeter of each room. Finally, determine if any other characteristics

of the floor plan invite the placement of additional movement joints. In this example, the

intersection of the nook area and kitchen/family room may be a reasonable choice.

Schluter®-Systems understands that the tile setter must take into account the needs of

his or her client in determining the placement of movement joints in a tile installation.

For example, a client may not wish to interrupt a continuous tile field that spans multiple

rooms. However, as indicated by the orange lines above, there are ways to meet

industry guidelines that will serve to provide the client with a durable installation that

remains aesthetically pleasing.

TCNA (Tile Council of North America)
EJ 171 MOVEMENT JOINTS

2025 Release, Pages 436-443

To request a physical or digital copy, please email CSRReno@schluter.com.