Dark Spots on New Granite Countertop
Installation Adhesive Stains in New Granite Countertop
We just moved into our newly built house and we had installed the giallo venetiano granite for our kitchen countertops. The granite countertop has a lot of similar dark spots all over that appeared after the installation.
I am pretty sure the counters are not sealed yet. I am hoping I could still do something about it before I seal it. What do you recommend?
Water can cause dark spots, but when the water evaporates.... so do the spots. Adhesives or glue
used during the granite countertop installation can sometimes be a problem.
The wrong adhesive or sometimes an additive used with the adhesive will produce dark gray-blue-green spots that may resolve within a couple weeks.... but often can persist and are sometimes permanent.
Granite installers will sometimes add an accelerant to the glue to help it dry faster. This accelerant can react with some granites and leach through to the surface causing these "Green Bloom stains".
Unfortunately, it is impossible to predict which granite may react. The actual cause is unknown and no significant pattern has been discovered. In other words, it doesn't appear to happen only with certain colors, etc. A consistent pattern
is typically seen with these glue stains. Most are the same size and shape and evenly spaced over the countertop since the glue is applied evenly and in a similar fashion in each spot.
Green bloom glue stains are also often seen along the seams in the countertop slabs, around the sink, or along the edges.
You will probably want to seal the countertops eventually, but I would NOT seal them until you remove the glue stains.
FYI... sealing prior to installation would not have prevented this since the glue is leaching through from the underside. Maybe if the underside was sealed but it never is and again, this problem is impossible to predict. Fortunately, most stains can be removed
with a simple procedure for cleaning granite countertops.
Just follow the detailed instructions in the Removing Granite & Marble Stains e-book
which includes info about green bloom installation glue stain removal.
Installation adhesive stains can be removed, but they tend to be difficult. It may take some time and you may need to repeat the stain-removal process many times.
Of course, your installer is responsible for the stains and removing them, so bring it to their attention. Certainly demand a re-install if the stains cannot be removed.