Crawfishking
New member
I thought I would post this in hopes of preventing somebody from going through the same nightmare I have.
Where I am building on the gulf coast you are required to have your building wind rated to 120mph for insurance purposes. Apparently that requires an engineered slab with 5,000 psi concrete. I know NOTHING about concrete but comparing my progress to others with normal concrete I have realized that what I have is way harder. I did ask the builder and he said there were no densifiers or curing agents added btw.
I've spent the past 4 weekends trying to prep my 1,400 sq' floor for epoxy coating. I had heard that grinding was the best way to go ( I had not found this forum when I started). I rented a dual disc diamond grinder the first weekend and after 2 days I had less than a 10th of the area done. I returned that machine and the next weekend I rented a diamabrush and machine from Home Depot. This seemed like it worked a little better at first because I at least had more visible scratches that the other machine but I quickly found out that these scratches were only superficial and I wasn't achieving a profile really at all. If I worked a small area for an extremely long time I was able to achieve a good profile but at the rate I was going I could tell it would take months to finish. I didn't want to spend that much time and I certainly couldn't afford the rentals.
So, I abandoned the grinders and started acid etching. I would work in small sections because I was by myself and I was a little nervous about the acid process. The acid worked much quicker than the grinders and is WAY cheaper.
Now, since I was a little nervous I tried not to get acid on the ground areas, not around the edges of the floor (metal building) and I sprinkled it kind of conservatively with a plastic watering can. After watering it, vacuuming up the rinse twice, then neutralizing with ammonia, vacuuming again, rinsing and squeegeeing out I could tell I didn't put down enough acid. The acid only works where it splashes down on the floor. Spreading the acid around with a broom does nothing. Once the floor dried I could tell where the acid hit and where it didn't.
So, this past weekend I was going to touch up the areas I thought needed more profiling. These areas were scattered throughout the floor in a somewhat uniform pattern so I really wound up retreating the entire 1,400 feet. I even got close to the walls by putting down plywood for splash guards.
While I was applying the acid (this time with a pump sprayer) I could see areas that still weren't done so I would hit them several times. After a while I got a little nervous about how much I was putting down so I would quit. I thought well maybe it will lift up with the pressure washer.
Nope! After doing all the rinse, vac, ammonia, rinse and power wash work I still have areas that need work. It looks a lot better and I think I can finish it all with some hand grinding.
Just fyi, I would wet the floor before putting down the acid and I was diluting the acid in 1:1 mixture.
If I knew what I know now I would have started off with acid, probably used full strength acid, and applied it till it looks like you want it before even bothering with rinsing it. I had so many conflicting descriptions of the purpose of the prep work that I really had no idea what it was suppose to look like or how much "smooth" area I could get away with. Also, make sure you have plenty of help. For my floor that should've been about 4 people to keep up with all the vacuuming and squeegee work. I can barely walk today my feet and back hurt so bad after running a squeegee up and down my pad while my buddy was power washing. Rubber boots with poor arch support can take its toll pretty quick. Take your time with the pressure washer. Once the floor dries you can see all the spots you missed.
To summarize, don't waste your time with grinders if you have 5,000 psi concrete. I wasted over $600 on rentals and more time than I could afford. I think if I wasn't nervous about the acid I could've been done in one day. I hope this saves somebody from making the same mistakes I did.
Where I am building on the gulf coast you are required to have your building wind rated to 120mph for insurance purposes. Apparently that requires an engineered slab with 5,000 psi concrete. I know NOTHING about concrete but comparing my progress to others with normal concrete I have realized that what I have is way harder. I did ask the builder and he said there were no densifiers or curing agents added btw.
I've spent the past 4 weekends trying to prep my 1,400 sq' floor for epoxy coating. I had heard that grinding was the best way to go ( I had not found this forum when I started). I rented a dual disc diamond grinder the first weekend and after 2 days I had less than a 10th of the area done. I returned that machine and the next weekend I rented a diamabrush and machine from Home Depot. This seemed like it worked a little better at first because I at least had more visible scratches that the other machine but I quickly found out that these scratches were only superficial and I wasn't achieving a profile really at all. If I worked a small area for an extremely long time I was able to achieve a good profile but at the rate I was going I could tell it would take months to finish. I didn't want to spend that much time and I certainly couldn't afford the rentals.
So, I abandoned the grinders and started acid etching. I would work in small sections because I was by myself and I was a little nervous about the acid process. The acid worked much quicker than the grinders and is WAY cheaper.
Now, since I was a little nervous I tried not to get acid on the ground areas, not around the edges of the floor (metal building) and I sprinkled it kind of conservatively with a plastic watering can. After watering it, vacuuming up the rinse twice, then neutralizing with ammonia, vacuuming again, rinsing and squeegeeing out I could tell I didn't put down enough acid. The acid only works where it splashes down on the floor. Spreading the acid around with a broom does nothing. Once the floor dried I could tell where the acid hit and where it didn't.
So, this past weekend I was going to touch up the areas I thought needed more profiling. These areas were scattered throughout the floor in a somewhat uniform pattern so I really wound up retreating the entire 1,400 feet. I even got close to the walls by putting down plywood for splash guards.
While I was applying the acid (this time with a pump sprayer) I could see areas that still weren't done so I would hit them several times. After a while I got a little nervous about how much I was putting down so I would quit. I thought well maybe it will lift up with the pressure washer.
Nope! After doing all the rinse, vac, ammonia, rinse and power wash work I still have areas that need work. It looks a lot better and I think I can finish it all with some hand grinding.
Just fyi, I would wet the floor before putting down the acid and I was diluting the acid in 1:1 mixture.
If I knew what I know now I would have started off with acid, probably used full strength acid, and applied it till it looks like you want it before even bothering with rinsing it. I had so many conflicting descriptions of the purpose of the prep work that I really had no idea what it was suppose to look like or how much "smooth" area I could get away with. Also, make sure you have plenty of help. For my floor that should've been about 4 people to keep up with all the vacuuming and squeegee work. I can barely walk today my feet and back hurt so bad after running a squeegee up and down my pad while my buddy was power washing. Rubber boots with poor arch support can take its toll pretty quick. Take your time with the pressure washer. Once the floor dries you can see all the spots you missed.
To summarize, don't waste your time with grinders if you have 5,000 psi concrete. I wasted over $600 on rentals and more time than I could afford. I think if I wasn't nervous about the acid I could've been done in one day. I hope this saves somebody from making the same mistakes I did.