Why use dangerous chemicals like acid to stain concrete when you can get beautiful results for less money and no acid?
Iron sulfate, also know as copperas, iron sulphate, and ferrous sulfate, can be used to stain your concrete a warm terra cotta or rust color for a fraction of the economic and environmental cost of acid stain.
The advantages of using iron sulfate to stain concrete are the:
- Beautiful, natural colors and variations is shades
- No fumes
- Non-toxic, "green" characteristics
- Very low cost of the materials
- Very little time required
- Easy to use
A 15-pound bag of Hi-Yield Copper as Iron Sulfate costs about $15 and will stain approximately 1,600 square feet of concrete. If you prefer blue shades, use copper sulfate, both products are available at some garden, feed and hardware stores.
Prepare the Surface
Thoroughly sweep and clean the surface to be stained. Use a mild cleaning solution such as Murphy's Soap. Use a putty knife or other scraper to remove any surface grime or irregularities that you don't want to show on your finished project. Rinse with clear water and sweep the surface again. Carefully tape or drape plastic sheeting over any surfaces you don't want to stain.
1 Pound Iron Sulfate
1 Gallon of Water
Combine in a non-metalic bowl using a wooden paint stick. Brush, spray (see note) or roll the mixture over the concrete. For spraying, save money by using the inexpensive lawn and garden pump handle types that cost about $10.
Mix only what you will apply within one hour since the colors fade once the solution has been prepared. For a darker, richer brown tone, add a pot of very strong coffee for every 3 gallons of the recipe.
To Create Visual Interest
For variations in shades, allow some areas to puddle and dry (requires a longer drying time) or sprinkle the area with sawdust or other absorbent materials you have around the house. If your back permits, use crumpled newspaper or a sponge to dab the color off of random areas.
For richer colors, apply a second coat of stain after the first application has dried overnight.
If you want to get even more creative, crisscross the area with duct tape or create a grid or other design. Use duct tape to create a firm seal so the stain won't run and ruin your design.
Spray or paint the area in thin coats with your iron sulfate solution and allow to dry. Repeat. Remove the tape as soon as the floor is dry to prevent the tape residue from adhering. The gray concrete will create interesting outlines for you "tile" floor.
Sealing and Protecting the Surface
Consider water-based, low or zero VOC (Volatile Organic Compounds) concrete sealers available in gloss or stain finishes. One gallon covers between 300 to 400 square feet. Always read the manufacturers guidelines. For example, to achieve a satin finish, some products require a coat of gloss to be applied first.
Note: To prevent clogging your sprayer, strain the solution through a cotton cloth.