Why am I having problems with my water-base cure and seal (Vocomp) on acid-stained concrete?

Manufacturers of chemical stains recommend that all acid-stain residue be neutralized and completely removed prior to sealing.

A solution of baking soda (sodium bicarbonate) and water (approx. 1 lb. of baking soda per five gallons of water) can be used to neutralize the stain. The solution should be applied until it stops fizzing. After neutralization is complete, the surface should be rinsed thoroughly with clean water several times to remove all remaining residue.

NOTE: Runoff may stain adjacent areas or harm plants. Runoff should be collected by wet vacuuming or absorbed with an inert material. All stain residue, runoff liquid, rinse water and absorbent materials used during application must be collected and disposed of in accordance with local, state, and federal regulations.

After rinsing is complete, a pH test should be performed on the surface to verify that no residual acid is present. If the color indicates a pH of 7 or higher, no residual acid is present and surface is ready for sealer application. If color indicates a pH lower than 7, further neutralization is required.

Failure to completely remove all acid residue prior to sealing the surface will cause appearance defects, adhesion loss, peeling, reduced durability, delamination and possible bond failure of the sealer.

The slab surface should be thoroughly dry prior to application of Vocomp.