We have a 3’x4′ floor mat that has been on our porch for about 10 years. We are about to replace it with a smaller semi-circular one. The problem is that the old one left a ghost of where it was. It looks like the porch slab weathered, but the area under the mat dident.
Is there any way that I can even out the color of the concrete? Is there any cleaner that would work? would parging the slab with morter do it?
Framing the floor inside a crawlspace foundation keeps a gable-end addition close to grade.
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Replies
A mild acid wash might do it.
pressure washer
May I suggest a spinner on that PW? Keeps away the zebra stripes.
I have a power washer, 2600psi, with 4 tips. Is there an acid that I should scrub on and let sit on the concrete then power wash it off?
Where do I get this acid? muratic acid?
The zebra stripes I referenced are the result of using the tips you mentioned on the ceement. Since the outside of the spray zone has a lower pressure than the inside, coupled with the variable distance from the surface, pressure washing ceement leaves an uneven look. Unles you go back over it several times, threatening the top layer of the ceement.
A "spinner" (http://www.ultimatewasher.com/pressure-washer-surface-cleaners.htm#A-flat-surface-cleaner) eliminates those marks by evening out those variables.
As far as the suggestion of using muratic acid, it does not need to be washed off with the machine. A simple hosing down will be sufficient following the application with a stiff scrub brush. But since it was NOT my suggestion, if trying this method, test in a unnoticable spot to gauge the effects.
Twere it me, I'd let the sun try to bleech out the spot following a non-invasive cleaning method. The acid would be invasive. A pressure washer with your tips would be invasive. A spinner on your machine - no.
I assume it's in the sun. If not, perhaps an epoxy coating with a slip resistant finish would work.
If it is in the sun, one can apply a cementatious topping (brushes, trowels, sprays, or squeeges on) in any color or texture you can imagine.