concrete floor too low....toilet hole to high [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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11-14-2005, 12:36 PM
We are down to bear concrete wall now in downstairs bathroom. The toilet hole is very high due to very high previous floor. It had dirt under thin mortar and old 1" x 1" tiles.

Question is how do we get floor back up? Should I use Durock to bring it up? The toilet hole is not is metal.

Also, if we use Durock, how do we adhere to concrete floor? What is wrong with Mastik for tile floor use.....would it be really bad to use it?


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11-14-2005, 01:34 PM
Sandra, welcome to the forums!

Backerboards are not intended to be attached to concrete floors. The best method is bonding deck mud the the slab. This will get your floor the whatever height you need and you can make it flatter than the original concrete. Deckmud is 5 parts sand to 1 part portland cement. You use a slurry of runny thinset to bond it to the slab. Needless to say, the slab must be clean so the thinset will bond.

11-14-2005, 02:01 PM
So Backer board useless in this bathroom of ours. You recommend to replace deck mud on the slab? long to dry deckmud and then how do we attached tile....use just thinset mortar for floor tile?

You can buy premixed 'deck mud' right?

This is turning into more than I was expecting.


11-14-2005, 02:04 PM
You can buy Sand Topping Mix which is 3:1 sand to cement and use it as it, or cut it with 1/2 bag of play sand. You can tile on it with thinset the next day.

Home improvement projects have a way of growing on you.;)

11-14-2005, 02:15 PM
We removed the original because it was coming up with the old itsy bitsy tiles.......I am wondering if we could have left it.

Adding it back will bring the floor up to toilet hole but also raises floor high at door frame.

With putting down deck mud, you just mix, pour and spread it out?


11-14-2005, 02:27 PM
Was your floor high at the door before?

You need only raise the floor so that the top surface of the tile is even with the underside of the toilet flange. In fact, you'll want to slide the tiles under the flange when you set them.

Check the shower construction thread for how to make and install deck mud. The only difference is that you will be painting the old concrete with thinset immediately before you place the deck mud. You do mix it, but it won't pour, so you place it with a shovel or trowel, then pack it down and flatten it. Read the liberry thread, and search the site for mud floors.

11-14-2005, 02:45 PM
Our floor was high at threshold....about 1 inch or so.

We 'paint' thinset mortar on concrete floor prior to putting down deck mud?

Could we use the Durock at all instead of deck mud? What is purpose of deck mud floor?

Seems like deck mud is like putting down concrete.....same kinda?

You guys are great for panicked homeowners!!!


11-14-2005, 02:51 PM
Something else.....

I read the the mix yum.

Do I need wire mesh for floor or did I read wrong?!


11-14-2005, 02:56 PM
You sould have to drive a bunch of concrete screws to put Durock on your concrete, even then the Durock folks won't honor their warrenty because you used their product in a non-approved manner.

The purpose of the deck mud is to raise the floor so the toilet flange won't stick up too far. It is about the best surface to tile over, too.

You want the thinset to be "wet" when the deck mud is applied. The thinset acts as a bonding agent because deck mud will not bond to concrete by itself.

No, you do not need the reinforcement, that's for wood subfloors. The slab is all the reinforcement you need.

11-14-2005, 06:38 PM
Just me talking - no one inmportant by trade but. . .

I would think if your floor was HIGH at the door frame/threshold previously, that would have been a real pain in the butt to step UP into your bathroom everytime. And, it sounds like you're looking to do it again.

And, to do it again, it appears it's gonna take some work. So . . . Why not just think about cutting that pipe off (ABS or Metal - either one - CAN be cut) and installing a flange at the proper height? If it sounds to complicated for a homeowner/DIY'er, maybe call a plumber in and have him do at least just THAT?

sw (shawn)

11-14-2005, 06:47 PM
Let me repharse HIGH.......The cement slab sits 1 1/2 inches below the toilet flange......or the toilet flange sits 1 1/2 inches above cement slab floor.

We want easiest way to get floor up to flange so we can have toilet sitting flushed (if you pardon the pun) with the new tile floor. Tile is 1/4 inch we need to make up difference of 1 1/4 inches........or am I just crazy?

Is it worth that to get a plumber.......we definitely are not using a step stool to get into the bathroom from Rec room.


11-14-2005, 06:57 PM
Hi Sandra -- that's what Shawn's saying, I think. No need to use a stepladder, just cut the toilet drain pipe to the height it needs to be -- it might require a little bit of work to expose the amount of drain you need, but it'll almost certainly be less work than bringing your entire floor UP 1.25 inches...

If it's too much work for you to DIY, get a bid from a plumber -- it's not a complicated job, shouldn't be too pricey.

11-14-2005, 07:05 PM
Okay....I'll bite.....what is 'not pricey'?!


11-14-2005, 10:30 PM
Hee hee. Sandra, I think I love you.

For us DIY-er's the "not pricey" bathroom that started at a couple of hundered bucks turns into a LOT more than planned! Only thing I keep telling myself is that somewhere, someHOW, SOMEWAY, I have GOT to be saving money!

One other option that I just thought of while re-reading your posts is I have seen the floor laid. The toilet is too high and they set "the pedestal" on a pedestal.

something like the following:

The one I remember actually looked very classy. It was a piece of solid marble placed under the toilet because the toilet was set on a wood floor and they didn't want any damage to the floor if the toilet leaked.

Just thinking.

sw (shawn)

11-15-2005, 11:21 AM
Okay.....what would you DIYers do?......Sound like putting in deck mud not too hard.......plumber possibly pricey.........toilet lifter is $79!!! Did I mention the bathroom floor is only 5 ft x 5 ft not a great big huge gigantic deck mud needed.

Main concern about cutting it toilet flange.......what if down the road it leaks at where flange was soldered or cut and then I am thinking there goes the floor.

Here is a thought....what are the chances of top floor bathrooms ...also small 1x1 tile......having deck mud that even possible on second floor. House again is 34 years old.

Advocado green tiles and old floor looking REAL GOOD RIGHT NOW!!!!


11-15-2005, 11:38 AM
Another question-

If we cut toilet flange, what with and how do we replace it.........Noticed I said IF..........unless you guys can convince me that I have the power and the possible talent to conquer this!!!!

With carpet reinstalled, the edge is not that noticeable.

Did I mention the beautiful antique advocado tiles that add so much pristine quaintness to my home it is almost worth keeping them!!!!

Dave Taylor
11-15-2005, 11:52 AM
If your floor is nice and flat.... go with Shawn's toilet lifter. Gives new meaning to "climbing on the throne" :--)

11-15-2005, 12:08 PM
I saw the toilet lifter.......maybe I am not seeing how it will work......the floor will still be low if I dont put in deck mud.......does the lifter hide the gap that will be present if we place tile right on concrete floor as opposed to putting deck mud downt so to bring floor up? It is about 1 1/4 inch gap approximately.

I am talking about 1 1/2 inches from concrete to underneath of flange now......if we add 1/4" 8X8 tiles, we still have 1 1/4 inch left under the flange.


11-15-2005, 01:52 PM
I saw the toilet lifter.......maybe I am not seeing how it will work......the floor will still be low if I dont put in deck mud.......does the lifter hide the gap that will be present if we place tile right on concrete floor as opposed to putting deck mud downt so to bring floor up? It is about 1 1/4 inch gap approximately.

I am talking about 1 1/2 inches from concrete to underneath of flange now......if we add 1/4" 8X8 tiles, we still have 1 1/4 inch left under the flange.


ARe you guys laughing at me?

11-15-2005, 01:58 PM
Nobody's laughing, at least not AT you!

And for the record, I don't know what "pricey" equates to in dollars. I know the toilet flange replacement isn't that hard, but that doesn't necessarily mean anything.

Can you get a picture of your flange and post it? That would help a lot. If it's on a slab, you might have to break out some of the concrete around the flange, enough to expose the pipe you need to attach a new flange. If it's a cast-iron pipe it might be worth having a plumber do it -- not sure, just know that CI is a little more difficult to work with.

11-15-2005, 02:02 PM
We almost sure it is cast iron.....feel like it, sounds like it. I will try to get photos with hubby.

What is a screed?

I am beginning to feel the need to do this mud floor to prove myself worthy of tile magic.


11-15-2005, 02:04 PM
Laughter AT people never happens here. Laughter in general happens all the time.

Ultimately, it is YOUR house and YOUR bathroom. Ya gotta do what YOU want to do. So - decide and just GO with it. If you decide that you don't care about the step into the bath - then go with the mud idea and start asking how to do it. Don't ask whether or not you SHOULD do it.

If you're asking what to do - I recommend cutting that flange down. Call in a plumber and just get it done. You can call and ask for a quote over the phone. They will try to tell you that they have to come out and look at it. Tell them that all you want is a general amount and tell them what you need done. There will probably be a trip charge plus the charge for the new flange. I have NO idea but I would think $100-$150 ish. Call around and see what you can find out. (or start asking friends that are plumbers or know plumbers.)

A bathroom that small - sounds like mudding the floor WOULDN'T be a HUGE job. I've seen people on this forum that have showers bigger than your whole bathroom. Either way - it sounds like once you get past the toilet flange problem - you've got nothing but blue skies!

sw (shawn)

11-15-2005, 02:06 PM
You can buy pre-mixed deck mud, called dry pack, at any DalTile for about $5 a bag.