Changing slope of pipes under concrete, or just fix the base?

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by alt, Jan 12, 2009.

  1. alt

    alt New Member

    Oct 29, 2007
    Sorry this is kind of long, but here is the backstory:

    The toilet in our basement bathroom sits on a concrete pedestal approximately 2" above the tile floor. According to the previous owners, who installed this bathroom in the previously unfinished basement just prior to our purchase one year ago, this was necessary because, in order to achieve the required 1/4" inch drop in the pipes, the elbow and flange for the toilet ended up being higher than the level of the floor. Since the basement ceiling is already very low, they opted to put the toilet on the pedestal rather than raising the level of the entire floor. Neither of us knows much about plumbing so we can only assume this is legitimate. (We have had many, many problems with other things they had improperly "fixed" or installed)

    When they created a form for the concrete base, they used the outline of the toilet they had purchased. But when they went to install the toilet, they discovered that it was too close to the wall and could not be positioned without knocking out the drywall. So they purchased a new toilet, but it did not have the same base shape as the previous one, but rather hung over the edges a bit (think rectangle toilet on top of an oval platform).

    My husband and I had not used this bathroom at all in the year we have lived here. We began using it one week ago when we removed the upstairs toilet and most of the surrounding floor in the upstairs bathroom (we removed it because the toilet began leaking due to a worn out wax seal, but after we removed the toilet we discovered that there had been previous leaks which had rotted the wood all the way through to the subfloor, and previous attempts to correct the problem had actually further damaged the wood!). Due to the extent of the damage, we did not feel comfortable replacing the toilet until the floor could be repaired. Then we decided this would be a good time to get rid of the yucky 60's vinyl on the floor, but after pulling it up we could see that the underlayment in the entire bathroom was warped and 'delaminating' and all the nails had rusted and lost their heads. So instead of just repairing the subfloor and underlayment around the toilet, we decided to remove all the the underlayment, make any necessary repairs to the subfloor, put down new underlayment, and then new vinyl.

    As of yesterday, we were still in the middle of getting up the old underlayment.

    Then yesterday afternoon I went downstairs to clean the basement toilet, and leaned on the tank as I was about to squirt bowl cleaner under the rim, and the toilet cracked from the bolts all the way through the trap and the toilet began leaking. We shut the water off and removed the toilet from the concrete base, and we could see that the surface of the concrete was extremely uneven and lumpy. I assume that it was this, combined with the toilet not being seated all the way on the platform, which caused uneven weight distribution and created the crack.

    In hindsight we should not have used the toilet downstairs at all until it could be replaced or properly seated. (In our defense, we did not have the resources to do so, and did not need it until the surprise fiasco with the upstairs bath last week when it then because a necessity).

    Now we have no working toilets in our home and are staying with the in-laws until at least one can be fixed. We still have to determine how much of the subfloor must be replaced upstairs (old 1x6 on diagonal, not tongue and groove though) and we both work full time so this might take a while.

    We are wondering if we can just have more concrete formed around the existing base downstairs to form a larger platform, and if it can then be sanded or smoothed out so it is not so lumpy and uneven on top. Then would we put some kind of "cushioning" between the toilet and concrete?

    The other option downstairs is fixing the problem with the plumbing and correcting the slope of the pipes, but we don't know if this is possible or even within our budget since (we assume) it will involve ripping up the concrete floor to access the pipes and essentially starting from scratch.

    We are really at a loss here, inexperienced and unsure how to proceed or even who to call. Plumber? Concrete expert?

    Please help!
  2. leejosepho

    leejosepho DIY scratch-pad engineer

    Nov 23, 2006
    disabled-retired industrial fabricator
    200 miles south of Little Rock
    It would be fairly simple to form a rectangular, concrete (and possibly temporary) pad (with enough room for your feet) around the flange and existing pad for the basement toilet, then set a new toilet there. If necessary, a little grout or mortar mix could also be used to make the area flat and smooth so the new toilet will sit properly.
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  4. alt

    alt New Member

    Oct 29, 2007
    Thanks. We have some other plumbing issues to be looked into, I think we will have them look at this before we do anything but I'm guessing it will be cost-prohibitive to tear out all the concrete around the pipes and start over. Pouring a new pedestal for the toilet to sit on seems the way to go for now.
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