Acid staining exterior concrete
Acid staining exterior concrete calls for a different approach than on interior staining. The biggest challenge outside is how the concrete was finished. Interior concrete floors are usually finished very smooth which really helps the acid stain look more marbleized, on exterior floors a broom finish is done to provide some traction and increase slip resistance. Other considerations are: is is badly stained? really rough? does it need patching? how do we clean it?has it been acid etched before? has it been sealed before?
Exterior stained floors will not have the high gloss finish of interior floors, even if a high gloss sealer is used, it will lose its luster and brightness once it is exposed to the elements, dirt and dust, it will still look nice but not as striking as a well kept interior concrete. This that not means acid stain is not for exterior concrete, it simply means it will be a different look, still attractive and pleasant but different.
Floor preparation for exterior concrete will usually include scrubbing with a detergent, pressure cleaning and making sure the surface does not have any oil on the surface. If the concrete has been sealed it will have to be stripped, any paint on the surface will also have to be removed otherwise the stain will not penetrate.