Check with several tool rental companies in your area. Explain your problem
and see what advise they offer. They should provide some useful suggestions
which may include:
- Using a very high pressure washer, which is much more powerful then the
"toys" that most homeowners possess. In addition to the very high
pressure, some of these units have heaters for the water. Just be certain
that you are renting a 120v unit or that you have the correct hookup if
you are renting a 240v unit.
- Using a pressure washer attachment which entrains sand with the water
output. This combines the features of a pressure washer with those of
a sandblaster. This gives less damage to the concrete, but it still
performs much better than just using high pressure water alone.
- Some careful use of a traditional sandblaster.
I've had reasonable good luck getting paint off concrete. Don't forget to
attack problem areas at a sufficient angle so that the water and/or sand has
the best opportunity to gain purchase under the paint and lift it off. If you
are using a traditional sandblaster, proceed with caution if you aren't
experienced. The sandblaster will "eat" into the concrete surface. That's not
a big problem if you don't use it often and you are careful to avoid going
too deep and careful to "feather-edge" problem areas.
You may want to consider getting quotes on hiring out the work after you
estimate what the tool rental will cost plus the value of your time. It may
be just as economical to hire out the work, plus you will toss the
responsibility of doing a quality job onto somebody else.