Expert: Dan Griffin - 9/11/2008

Question
Our driveway was sealed with a stained sealer approximately 1 year ago.  The sealer is already fading in certain areas where the driveway is more porous.  One can also see the roller marks on the sealer.  I was told that we would have to sand off the sealer in order to fix or reseal the driveway.  What are your thoughts?

Answer
There sure is a bunch of different chemistry in concrete stains and sealers.  It is best, just as in woodworking, not to mix chemistry families.  If you have any way to contact the installer to find out brand and type it would sure make it easier to stay compatible.  It is very important to find out if it was a  breathable acrylic sealer that would allow vapor transmission through the finish, solvent based, or epoxy based.  If you are seeing roller tracks, it sounds as if it may have been applied on a hot windy day that made the sealer set too quickly.  I am not familiear with sanding off existing sealer unless something is delaminating.  Again, try to find out what the original was.  Failing that, contact a local decorative concrete man, offer to pay him for his time and expetise, explain your problem, let him come to see it and give his professional opinion.

Here is some information about the issues:
http://www.thestampstore.com/Technical/datasheets.php#techdatasheets
and
http://www.concretenetwork.com/