May 12, 2012
We decided to stain the concrete slab for our finished floor. We love the look of acid staining, but didn't want to work with the acid. We learned about staining concrete with iron sulfate, a common garden soil additive, from some local contractors who specialize in natural building. Benefits of the iron sulfate stain are that it is very inexpensive compared to acid staining and it is safe to handle for both producers and end users.
We did additional internet research on applying the stain and found some variety in techniques. We first tried mopping on the stain but later used the garden sprayer to apply. We didn't see any benefit to the mopping technique-- it was harder to do and created indelible patterns (not too unsightly, but...). Using the sprayer was much simpler and applied the stain evenly, as long as the liquid was strained with a cloth prior to use.
The stain did not look very good at first and several times we worried that we had ruined the floor! But after the 6th coat, we rinsed and scrubbed off the iron residue and found the colors and patterns to be very attractive. Once construction is complete, we will seal the floor with a glossy sealer to restore the "wet look" which has rich color and interesting textures.
Scrubbing and rinsing the residue
After rinsing. We expect the finished floor to look like this after we apply a glossy sealer.
When dried, prior to sealer, it looks like this...
