You have a choice to choose from two types of concrete stains: acid stains and acrylic stains. Acid stains are derived by a chemical reaction with free lime in the surface to get a natural looking transparent color. They craft a dappled, multicolored, mottled coloring. It is a natural characteristic of any concrete surface to react in a different way to acids stains and that's what makes each job look unique.
Acrylic stains on the other hand are water based with pigments that trickle down to the pores and stick to the concrete. Thus they offer better consistency with semi translucent color like that of a dye. An in built advantage of acrylic stains is that they help to mask flaws and discolorations while acid stains actually highlight them.
How to decide whether acid or acrylic stains will work and look better?
In a ma majority of the cases both will work equally work and it would depend on your personal choice to choose one. However, it also matters to gauge how old the concrete is.
A fifteen to twenty years old concrete would not give as satisfactory results with acid stains because a lot of the free lime has already leeched away. Thus for such exterior concretes an acrylic stain will prove a lot better due to its better porosity over time. Acid stains are definitely more effective with not so old concretes that have a lot of free lime on offer. Acrylics could be a preferred choice to help disguise the repairs like patching pop outs or scaling. Acid stains would rather make any repairs more conspicuous. As acid stains do not really need a lot of penetration for imparting color to concrete they are found better for toweled interior surfaces that have less porosity.
Before you really get started with it, you shouldn't have too high expectations, no matter are you doing it outdoors, on your driveway or in a garage. Staining would surely make a dull, gray concrete look better and colorful but it's just not possible for anybody to really predict the final finished look, all the more so if you are using acid stains. The logical explanation for that is that every concrete surface is singular and would react to stains differently.
Don't be surprised to find at the end that two slabs, though treated with the same stain, present a different look. Even seasoned pros are unable to foretell the exact result of a staining job. That's why it's not a good idea to try to exactly match the color of concrete to anything else such as brick or siding. There are very dim chances of your being successful. You would be more practical in choosing a complimentary color or shade for your concrete. For example it would be better to choose a dark brown stain for a light brown siding.
Preparation is the most significant part of staining. Have a prolonged thought at how would you like the concrete to look finally and don't be in a rush to get the surface ready for application of stain. Else, you might have to undertake a major overhaul of the surface.
The process of concrete staining on your own is not too difficult but you have to make an honest effort and get that feeling of a project well done!
