In this scenario we suggest you skim coat the existing concrete - allowing the patina to affect the skimcoat rather than older / potentially moisture affected concrete.
The primary concern regarding application of Patina Acid Stain is the preparation - a rough skim coat will leave the acid to sit in pools in deeper areas, causing much darker acid staining. Where as a "water finished" skimcoat will leave a more level area allowing a smoother transition between the Acid Stain effects.
Some of our most common questions regarding Patina Acid Stain:
Is Patina Acid Stain difficult to apply?
No, the actual application of Patina Acid stain is very easy. Make sure you use a plastic sprayer (the acid will affect any metal in sprayers), and apply evenly. The difficult part of applying Patina Acid Stain all comes down to the preparation of the surface area.
Can anyone do it?
Yes, Anyone can apply it, as long as you fully understand the potential risks and hazards involved with using Concrete Acid. Use the correct PPE and do not get the acid on any surface you do not wish to stain.
What’s the best sealer to use over that? Polyurethane?
Any sealer will work, but we suggest polyurethane or 2 pack epoxy sealer.
Can Patina Acid Stain be used outdoors?
Yes, The main issue with using Patina Acid Stain outdoors is not the actual Acid Stain - its the sealer. When you use sealer in an outdoor situation on top of a smooth surface, it allows the surface to become very slippery when wet. If you are going to use it outdoors and expect foot traffic or vehicles to drive on it - please add a liberal amount of non slip / skid additive to prevent this from happening.
What are the coverage rates of Patina Acid Stain?
The coverage rate is dependant on and varies widely due to porosity, texture, composition, age, preparation, application technique and other factors in relation to the cementitous surface.
An average coverage rate would be: 5-7.5m2/l/coat. (20L / 100m2)