Step 4 — Apply Monoform Primer to the Airform’s interior, at a rate of about 300 square feet per gallon. It can be applied with an airless sprayer, but must be applied at least 30 minutes or more (up to a few days if it remains clean) before spraying the first layer of Shotcrete. The Monoform should be dry but sticky to touch.

Step 4 — Apply Monoform Primer to the Airform’s interior, at a rate of about 300 square feet per gallon. It can be applied with an airless sprayer, but must be applied at least 30 minutes or more (up to a few days if it remains clean) before spraying the first layer of Shotcrete. The Monoform should be dry but sticky to touch.