PRIMER-PS is a ready-to-use primer specifically formulated to improve the bond between Schluter's peel-and-stick membranes (DITRA-PS, DITRA-HEAT-PS, DITRA-HEAT-DUO-PS) and substrates that are harder to stick to. Think OSB, gypsum concrete, vinyl, and plywood — surfaces where the PSA alone might not grab hard enough for a permanent bond.

It's a one-component, solvent-free, water-based formula. No mixing, no additives. Pour it out, roll or brush it on, let it dry to a clear film, then apply your peel-and-stick membrane directly over it.

When do you actually need it?

• Always use on: OSB (including Advantech), gypsum concrete, existing vinyl or VCT
• Recommended on: Plywood in humid environments, older concrete with surface contamination
• Not needed on: Clean, smooth concrete — DITRA-PS sticks directly
• Rule of thumb: If the substrate is porous, textured, or you're unsure — prime it. A $30 bottle of primer is cheap insurance against a membrane that lifts.

Application

• Stir thoroughly before use (settling is normal) — do NOT dilute
• Apply with a paint roller, brush, or pour from container onto substrate
• One even coat — avoid puddling (excess primer = longer dry time, weaker bond)
• Let dry completely to a clear, tacky film before applying membrane
• Room temp between 40–85°F (5–30°C), humidity 35–55%
• Coverage: approximately 200–350 sq ft per gallon depending on substrate porosity

Storage

• Shelf life: 12 months from manufacture date (check label)
• Store between 50–90°F (10–32°C)
• Survives 1 freeze-thaw cycle at 0°F (-18°C) — thaw at room temp before use
• Keep container sealed when not in use

Specs

• Type: Ready-to-use, water-based primer
• Compatible with: DITRA-PS, DITRA-HEAT-PS, DITRA-HEAT-DUO-PS
• Substrates: OSB, plywood, gypsum concrete, vinyl, concrete
• Coverage: ~200–350 sq ft/gallon
• Dry time: Varies by conditions — clear film indicates readiness

Pairs with

• All Schluter peel-and-stick (-PS) membranes
• DITRA-ROLLER — for embedding membrane after primer dries