(206) 949-5683, Top Rated Plumber, Seattle
Page 1 of 2 12 LastLast
Results 1 to 15 of 19

Thread: New basement bathroom - Bad concrete pour?

  1. #1

    Default New basement bathroom - Bad concrete pour?

    Moving right along on my basement bath project, the last thing I thought I'd screw up was the concrete patch. - I'm not real sure what to do at this point, but I poured 14 bags of 80lb quickrete and one week later, the finished floor surface is rough and gritty. Anytime I walk on it I kick tiny particles of sand. If I sweep it w/ a push broom, cement dust kicks up into the air. I'm thinking I used too much water and/or finish-troughed it too much.

    My intent is to tile the bathroom and I don’t want to have bonding issues w/ the mortar down the road. Does anyone know of any products I might be able to put on it to fix the issue? Is the only fix for this to jackhammer it back out and re-pour?

    Any thoughts, comments, opinions appreciated…

    Thanks - Jeff

  2. #2
    DIY Junior Member BigBoschMan's Avatar
    Join Date
    Feb 2007
    Location
    New York
    Posts
    8

    Default

    Are you good with a hand trowell?...If so,either do a drymix mortar bed before your tile project or use latex modified thinset to make a smooth surface for your tile.

  3. #3
    DIY Senior Member harleysilo's Avatar
    Join Date
    May 2006
    Location
    Georgia
    Posts
    101

    Default

    Have you vaccumed it with a shop vac to get all the dust and sand etc. up? To ensure that it just not deteriorating each time you walk on it?

  4. #4
    DIY Senior Member TedL's Avatar
    Join Date
    Sep 2006
    Location
    NY Capital District
    Posts
    604

    Default

    A self-leveling mix might be the easiest route.

  5. #5

    Default

    I scrubbed the whole area yesterday w/a very coarse, hard brush (made for cleaning concrete) then took the shop-vac to it. That definitely seemed to make it better in the sense that there is not as much sandy, gritty substance coming off....but it still comes off it you drag your foot accross it while pressing down.

    There is definitely some good, hard surface that I think/hope something will adhere to. So are you thinking the latex modified thinset might bond to it OK?

    My surface is nice and level w/ the old floor so I don't think a floor-leveler would really work unless I was to take some of the new pour out or just do leveler over the whole floor, a 6x6 area...never used floor leveler...can I do areas that large?

    Jeff

  6. #6
    DIY Senior Member TedL's Avatar
    Join Date
    Sep 2006
    Location
    NY Capital District
    Posts
    604

    Default

    6x6 is a small area, and you can put it on in a very thin layer to save material cost.

    You could do a whole basement, but that can get pricy.

  7. #7

    Default

    That may be my best option then. No drywall or anything up at this point, just framing, so the bottom plate would make a good perimeter to run the leveler up to. Thanks for the reply.

    Jeff

  8. #8
    Moderator & Master Plumber hj's Avatar
    Join Date
    Aug 2004
    Location
    Cave Creek, Arizona
    Posts
    25,618

    Default concrete

    One problem could be that that concrete mix is often coarse. I often add some Portland to it to make a richer mix.

  9. #9
    Homeowner geniescience's Avatar
    Join Date
    Nov 2005
    Location
    humid summers hot, humid winters cold
    Posts
    2,152

    Default just tile it

    Your initial description talked about a problem with dust and grit. I'm not there to see it, but I think that any thinset will stick to it. A latex additive is even better.

    If you are happy with the level-ness, you don't need to spend big money leveling it with Self-Leveling Cement (SLC).

    Nobody has ever posted about thinset not sticking. Just tile it.

    David

  10. #10
    DIY Member GregO's Avatar
    Join Date
    Oct 2004
    Location
    Virginia
    Posts
    73

    Default thinset

    As long as the dust/sand/grit stops coming up, I agree that using a high-quality thinset should do very well. Actually, a coarse surface is ideal because it creates a far better mechanical bond.

    Greg

  11. #11
    DIY scratch-pad engineer leejosepho's Avatar
    Join Date
    Nov 2006
    Location
    200 miles south of Little Rock
    Posts
    2,474

    Default

    Quote Originally Posted by JeffV
    I poured 14 bags of 80lb quickrete and one week later, the finished floor surface is rough and gritty ...

    Does anyone know of any products I might be able to put on it to fix the issue?
    I had the same kind of problem when I made a new lid for my septic tank last summer, and in my own case, I believe a weak mix needing more portland, like hj said, was the cause. I would also say you will be just fine finishing it off with some thinset prior to tiling. Or, maybe something like Mapei's compatible "Planipatch" might be a little better if you have to fill 1/4" or more.

  12. #12
    Homeowner geniescience's Avatar
    Join Date
    Nov 2005
    Location
    humid summers hot, humid winters cold
    Posts
    2,152

    Default patching mix

    yes, a patching mix (a cement product) or a grout mix (which is also a cement product) will be good.

    david
    edit: if you are not happy with the surface flatness or if you need to raise the height. Otherwise just tile it.

  13. #13

    Default

    Thanks for all the suggestions. You all have been a great help.

    I do believe I can get away w/ just tiling over it. At minimum I may have to use the SLC to fill in a couple very small low areas in my pour.

    The sand/dust are definitely down to a minimum now and I'm thinking the thinset will bond to it w/o issue. I may even test a small section.

    This is truly a lesson learned. I'm just glad it was a small pour. Had I done anything more substantial or needed to have a smooth finish this could have been really ugly.

    Thanks again everyone - Jeff

  14. #14
    Retired Defense Industry Engineer jadnashua's Avatar
    Join Date
    Sep 2004
    Location
    New England
    Posts
    21,388

    Default

    Use a long straightedge to determine the extent of the depressions you want ot fill. Thinset can be used up to about 1/4", and is cheaper. You can do it in layers if you let it cure inbetween, too. I'd consider that before I tried SLC (although I've used both). SLC has an extreemely short pot life...you mix it, pour it, and stand back and watch it harden. You have nearly no time to feather the edges, and unless you are covering the whole area so you don't have edges is tough, since determining exactly the right amount to fill in the bowl can be hard, and you have to use it all up and feather edges all in a few minutes. If you try to work SLC once it starts to cure, you will end up with a really big mess. It flows, but when it is thin, you need to move it around to wet the surface, otherwise surface tension will keep an edge; sort of like cold honey - the edge will have nearly a circular shape, not a feathered edge unless you spread it out.
    Jim DeBruycker
    Important note - I'm not a pro
    Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014

  15. #15
    In the Trades Bob NH's Avatar
    Join Date
    Oct 2005
    Location
    New Hampshire
    Posts
    3,307

    Default

    There are different grades of SackCrete or QuickCrete.

    The least expensive should not be used for any project that requires finishing. It has too much large stone, and too little sand and cement.

    Problems with concrete often arise from too much water and too little water.

    When it is mixed, the mix should be only as wet as necessary to place and finish it. It should stand in a pile. It should not run. When you are finishing it, you should float up enough fines (sand and cement) to get a smooth surface. If you get a puddle of water when you finish it, you used too much water.

    After it sets up and is not susceptible to being washed away, it shold be kept moist. The cement needs water to bind the molecules into what is called a hydrate. Too little moisture, as from low humidity in the winter, prevents curing of the surface.

    Concrete should never be allowed to freeze until it is fully cured; at least a couple of weeks.

    At this point, you probably need to scrub off the loose stuff and go with a tile set mix that may be used thick enough to give you the spacing that you need. http://www.tileusa.com/thinset-mortar_faq.htm#medmortar

    You are not likely to be able to "fix" the problem as good as you can do with a medium bed thinset.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •