aavgerinos
Member
Background info:
Home purchased about a year ago. Was a rental for many years, garage was carpeted and converted to a living space. The upside is that there was minimal grease/oil spots under the carpet padding. After spending a few days browsing this site, last year I purchased 2 packs of Rustoleum Epoxyshield Professional (solvent based stuff) and 1 box of their Clearcoat in hopes of creating a a kickass floor for my new house.
Prior to this past weekend, my plan was as follows:
1) Rent a 3500psi pressure washer from Home Depot. Remove as much grease, plaster, paint, and tar as possible from the flooring. First with detergent, and second with a degreaser like Simple Green.
2) Acid etch to remove any stubborn bits of plaster and the like using Muriatic Acid purchased from a pool supply store (cheaper than Home Depot, right?).
3) Pressure wash again to completely remove acid. Check pH to make sure acid has neutralized. Keep a large supply of baking soda on hand just in case.
3) Fill gaps around the perimeter with new concrete
4) Let slab dry/cure 3-4 weeks
5) Vacuum flooring to remove all dust
6) Follow directions on box for epoxy.
So the pressure washer and acid didn't work as well as I had hoped. The ZEP concrete soap degreased well enough, but overall the floor still needs a lot more work.
Here are a couple photos of the floor prior to cleaning:
I used the pool grade muriatic acid available at our local Home Depot. Strength is 14%. Undiluted. Here are the results after a day's labor:
We applied the acid, scrubbed it "into" the surface, and then let it sit for 10-15 minutes. Then washed it down with the pressure washer and followed that up with the high pressure setting to try and remove the paint, plaster, and rust shown above.
It didn't work as well as I had hoped. At this point, I think a Shotblaster would be a better method of preparing the surface. I'm assuming that will be strong enough to remove the rust and stubborn paint.
My original goal with this garage floor was to seal it and a couple inches of the surrounding wall with the epoxy. Assuming the flooring had a natural slope, I could simply hose down the garage from time to time.
However, after spending all day working on the floor I realized something very important: This slab is in terrible shape.
It looks like the slab has slid under the house slab an inch or two. In addition, the slab looks like it's only 3-4 inches thick, I doubt it's reinforced, no gravel base, probably doesn't have a moisture barrier of any sort, and the slope of the floor was either terrible to begin with or has changed over time.
So now I have to wonder: Does it make good sense to spend another couple hundred bucks Shotblasting the floor when there's a good chance it's just going to bubble and crack anyway?
But how soon will it fail? Maybe Shotblasting the epoxy floor will mean good adhesion for only 10 years on this crappy slab versus 20 years on a good slab? Or maybe I cut my losses, sell the epoxy on Craigslist, and use concrete paint every 2-4 years?
In the end, I think I just want a durable floor coating that keeps the garage looking reasonably clean for the next 7-10 years. It doesn't have to be glass smooth or show room quality as I have no intentions of filling the little divots and small cracks.
I also need to figure out how to best fill those large gaps in the slab. Unfortunately pressure washing and acid etching didn't remove all the paint and foam so I fear the bond between the old slab and new concrete will be mediocre at best. I foresee a hairline crack developing even if I use some sort of expansion joint.
Do I bother with an expansion gap/joint if it's just going to crack anyway? On the other hand, a hairline crack is much smaller than a 2 inch wide gap. I suppose the correct/professional way to fix the gap is to use a concrete saw to make the gap much larger (like 6-12 inches?), clean up the slab bonding surfaces really well, add the expansion joint near the wall/driveway, and fill the rest with concrete. But, is it worth it when the rest of the floor is in crappy condition? Also, do expansion joint pieces come in difference thicknesses? Home Depot has a fiberboard that looks to be about 3/8" thick and I'm finding remnants of a similar material in a thickness 1/3 that size.
What would you do in this situation?
Home purchased about a year ago. Was a rental for many years, garage was carpeted and converted to a living space. The upside is that there was minimal grease/oil spots under the carpet padding. After spending a few days browsing this site, last year I purchased 2 packs of Rustoleum Epoxyshield Professional (solvent based stuff) and 1 box of their Clearcoat in hopes of creating a a kickass floor for my new house.
Prior to this past weekend, my plan was as follows:
1) Rent a 3500psi pressure washer from Home Depot. Remove as much grease, plaster, paint, and tar as possible from the flooring. First with detergent, and second with a degreaser like Simple Green.
2) Acid etch to remove any stubborn bits of plaster and the like using Muriatic Acid purchased from a pool supply store (cheaper than Home Depot, right?).
3) Pressure wash again to completely remove acid. Check pH to make sure acid has neutralized. Keep a large supply of baking soda on hand just in case.
3) Fill gaps around the perimeter with new concrete
4) Let slab dry/cure 3-4 weeks
5) Vacuum flooring to remove all dust
6) Follow directions on box for epoxy.
So the pressure washer and acid didn't work as well as I had hoped. The ZEP concrete soap degreased well enough, but overall the floor still needs a lot more work.
Here are a couple photos of the floor prior to cleaning:
I used the pool grade muriatic acid available at our local Home Depot. Strength is 14%. Undiluted. Here are the results after a day's labor:
We applied the acid, scrubbed it "into" the surface, and then let it sit for 10-15 minutes. Then washed it down with the pressure washer and followed that up with the high pressure setting to try and remove the paint, plaster, and rust shown above.
It didn't work as well as I had hoped. At this point, I think a Shotblaster would be a better method of preparing the surface. I'm assuming that will be strong enough to remove the rust and stubborn paint.
My original goal with this garage floor was to seal it and a couple inches of the surrounding wall with the epoxy. Assuming the flooring had a natural slope, I could simply hose down the garage from time to time.
However, after spending all day working on the floor I realized something very important: This slab is in terrible shape.
It looks like the slab has slid under the house slab an inch or two. In addition, the slab looks like it's only 3-4 inches thick, I doubt it's reinforced, no gravel base, probably doesn't have a moisture barrier of any sort, and the slope of the floor was either terrible to begin with or has changed over time.
So now I have to wonder: Does it make good sense to spend another couple hundred bucks Shotblasting the floor when there's a good chance it's just going to bubble and crack anyway?
But how soon will it fail? Maybe Shotblasting the epoxy floor will mean good adhesion for only 10 years on this crappy slab versus 20 years on a good slab? Or maybe I cut my losses, sell the epoxy on Craigslist, and use concrete paint every 2-4 years?
In the end, I think I just want a durable floor coating that keeps the garage looking reasonably clean for the next 7-10 years. It doesn't have to be glass smooth or show room quality as I have no intentions of filling the little divots and small cracks.
I also need to figure out how to best fill those large gaps in the slab. Unfortunately pressure washing and acid etching didn't remove all the paint and foam so I fear the bond between the old slab and new concrete will be mediocre at best. I foresee a hairline crack developing even if I use some sort of expansion joint.
Do I bother with an expansion gap/joint if it's just going to crack anyway? On the other hand, a hairline crack is much smaller than a 2 inch wide gap. I suppose the correct/professional way to fix the gap is to use a concrete saw to make the gap much larger (like 6-12 inches?), clean up the slab bonding surfaces really well, add the expansion joint near the wall/driveway, and fill the rest with concrete. But, is it worth it when the rest of the floor is in crappy condition? Also, do expansion joint pieces come in difference thicknesses? Home Depot has a fiberboard that looks to be about 3/8" thick and I'm finding remnants of a similar material in a thickness 1/3 that size.
What would you do in this situation?
