Not all thin-set works with Schluter membranes — use the wrong mortar and you can compromise adhesion, void the warranty on your KERDI or DITRA installation, or both. ALL-SET is Schluter's modified thin-set, engineered specifically for their system and tested to meet warranty requirements.

ALL-SET is the safe, universal choice. Use it when you're bonding DITRA or DITRA-HEAT to a wood subfloor (plywood or OSB), bonding KERDI to walls, or setting tile over any Schluter membrane. If you're not 100% sure what substrate you're working with, ALL-SET is the mortar to reach for.

When to use ALL-SET vs. Schluter SET

• DITRA over plywood or OSB → ALL-SET (modified required for wood)
• DITRA over concrete or gypsum → SET (unmodified preferred)
• KERDI on walls → ALL-SET (modified preferred for better adhesion)
• Tile over any Schluter membrane → either works (ALL-SET is safe; SET is traditionally specified)
• Not sure? → ALL-SET

Key specs

• Type: Modified thin-set (ANSI A118.4T, A118.11, A118.15)
• Colors: Grey and white
• Open time: ~30 minutes at 70°F
• Walk-on time: 12 hours at 70°F
• Grout after: 12 hours
• Coverage: ~40–50 sq ft per bag when setting tile over membrane
• Shelf life: 2 years (unopened, protected from freezing)
• Lifetime warranty when used correctly with applicable Schluter products

Why the mortar matters

Unmodified mortars are chemically compatible with DITRA's polyethylene. Modified mortars — like ALL-SET — add polymer binders that improve adhesion on wood and porous substrates. Use the wrong type in the wrong application and you may get a slip plane between the membrane and substrate, or reduced bond strength on a wood floor where movement matters most.

Pro tips

• Mix to a fluid, creamy consistency for bonding membranes — slightly stiffer for setting tile on top.
• For DITRA, use a 1/4" × 1/4" square-notched trowel or the Schluter DITRA-TROWEL. Full fleece coverage is the goal.
• Don't mix more than you can use in 30 minutes — especially in warm or dry conditions.
• Never use ALL-SET on frozen or near-freezing substrates. 50°F minimum substrate temperature.
• Use a DITRA-ROLLER after embedding membrane to ensure complete mortar contact under the fleece.

Use with: DITRA, DITRA-HEAT, DITRA-HEAT-DUO, KERDI, KERDI-BOARD.