roomtogrow

we bought a home with an unfinished basement that has failrly rough floors. we'd like to stain the concrete; but, obviously, the first step is to determine how much of a task it'll be to smooth out the concrete. some spots aren't so bad, and other spots have some lines that were left from when the concrete was poured. how do i know how much i need to grind the floors down, or do i try to polish it first? i've got 2100 sq. ft. of basement; is it feasible to do this job on my ownwith a rental grinder?

CallMeVilla

There is a concrete grinder that looks like a large floor polisher. It can do a very nice job flattening out those ridges and problems. The task is dirty and challenging but you can do it yourself. I would start with rough stones on the disk and then take it down to finer stones to get the best possible surface before staining.

Smoother is better.

I have done staining too. You will acid wash the final surface but that will not fix seams or ridges. Remember, the stain will puddle in those seams.

Good luck!

roomtogrow

thanks for responding to my thread. a couple more questions if you don't mind:

1) would you suggest trying to polish/sand the existing floor before going at it with a grinder? (obviously, you don't have the benefit of having seen the existing state of the floors; but, just wanted to know if that made sense to try that first.)

2) if i do have to grind the floors, is it likely that i will have to overlay the floor with a thin layer of concrete or self leveling concrete, or should i be able to polish with a fine grit sandpaper after grinding?

thanks for your help.

CallMeVilla

OK, I would suggest light grinding and inspection first. Lay a long level (8') on the floor to check for big dips. Grind as needed to remove issues. Think of this as if it was wood. Coarse sanding first, followed by fine sanding last, right? Same with the concrete.

If you pour new leveling concrete, I would do the whole floor, not just dips. The variation in concrete finishes (self leveling is very smooth) may telegraph once you stain it.

I have seen trowel finish floors stained and they were just fine. You do not have to have a polished floor before staining unless you are being VERY upscale with the basement. For example, I did a patio which was troweled smooth in part and heavily weathered in the other section (pitted). The troweled segment turned out looking really good -- but the pitted segment gulped the stain and just could not compare.

Wuzzat?

Never heard of it till now.

http://en.wikipedia.org/wiki/Self-leveling_concrete

nealtw

Wuzzat: you've lived a sheltered life, it's been around for ever well a long time anyway.

BridgeMan

To the OP,

Unless you are an experienced concrete finisher, you might want to consider paying someone to place a thin floor leveler over the 2100 S.F. Trying to do it yourself with limited finishing skills is asking for (lots of) problems.

CallMeVilla

Good advice BridgeMan . . . You have to be systematic and meticulous in the back and forth and overlapping with a grinder. We used a two man team - one to guide the grinder left and the other looped the power cord around the motor as a lassoo to pull the grinder back to the right. We worked across every part of a 1800 sq ft area.

We vacuumed completely then checked for dips or bumps with the straight edge. Bumps were reduced systematically. In the end, the entire floor (which had been tiled with Mexican pavers and thinset) was within 1/8" tolerance throughout. There was no need to fine polish.

I would say, if RoomtoGrow does not have the skills, hire a guy who does and work together.

Wuzzat?

There are definitely gaps in what I know. . .I need to spend more time in HD and more reputable building material places.

BridgeMan

Anyone who hopes to increase his/her DIY skills by "spending more time in HD" is using the wrong approach. Learning things from people who wear orange aprons can be very risky, in terms of the depth of knowledge being shared. Far better to spend some time observing (and asking questions of) the professionals actually performing the skills you wish to acquire.