PWR™ Powdered Water Repellent
PWR is a dry mix water repellant from the folks at SaverSystems. It's designed to be added to mortar mix to make it waterproof. PWR comes in a 32 oz. container with a measuring cup. Add one ounce for each 15 lbs. of mortar mix. When you do crowns or tuckpointing it will be waterproof when it cures.