Best way to prep stem walls

[Docklobster]

Hi all just wanted to get an idea of how everyone was prepping their stem wall before epoxy, I have about 5" of height and 4" across the top of mine. The top is really rough so I am thinking of using the angle grinder on the top and sides and following up with the acid, but I was concerned with the acid getting near the studs and anchor bolts on the stem walls?

Thoughts/tips - How'd you do it?

Thanks...

 

[cookiemcsnax]

Since I just did it two days ago...

I found that if anything the angle grinder was faster on the stem walls than the floor. Depending on how yours was poured this may be different, but my stem walls were much more porous and (it seems) much softer concrete. One pass at reasonable speed was enough to get a nice surface. This was especially true of the verticals - the top took a little more grinding. But they went much faster than anticipated.

Haven't etched so can't help you there.

 

[boiler7904]

I haven't done mine stem walls yet. Mine range from 6-8" tall x about 3" wide on 3 out of 4 sides with no horizontal ledge on the 4th. I've thought about doing a light grind and then block filler and regular exterior masonry paint in a color that accents the floor.

I too would be leary of letting the acid come in contact with anything but concrete. Seems like you would be inviting corrosion on the anchor bolts - not sure what it would do to the bottom plate. The rinsing / neutralization process would mean a lot of water on your framing which isn't exactly a good idea. I know that framing usually gets rained on before the shell is dried in but once the building is closed, it takes a lot longer to dry out.

Grinder is probably the safer bet.

 

[JD in DFW]

Don't need to. Most are rough finish and the epoxy will take right to it. I would not waist the time and effort. Plus how much foot and tire traffic do you see your stem wall seeing???

Best of luck with the floor.
JD

 

[Sebastian]

I just hit mine with the angle grinder, but like JD said they are pourous enough and do not need too much prep. Also, they wont take any wear and tear.

 

[bigstuie]

I did not epoxy the stem walls. I used regular cement paint in a dark gray to give them a clean look, and then had the Devran 224HS colored in the exact shade of gray and It matches perfectly.

 

[Irondrive]

Everybody is correct. I never prep stemwalls, unless the previous coating, if any is peeling. You'd be amazed at what a full chip floor can hide.