Novice at DIY, remodeling bathroom and need your help, please [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


View Full Version : Novice at DIY, remodeling bathroom and need your help, please

03-06-2007, 01:34 PM
Hi all ;)

I'm a novice at DYI, so I am having to rely on books, internet, and people at home improvement stores to get resources, but I am getting some conflicting or not enough information when it comes to tiling.
I will have many questions along the way, but I will post them as I go.

My first question is how to determine wheather or not the floor is level enough for tiling.

I've learned the existing wood subfloor is suitable for tile installation. However, this subfloor has some high and low spots. (The high spots are in the middle.)

First, I was told by a professional tile installer that I will have to pour some kind of compound (I forgot the name), which will act as tile underlayment (I will not need to use cement board on top of it). Then, I was told by another remodeling professional that the floor is level enough that I can just place cement board over mortar, and that will make the floor completely level. Finally, I went to Home Depot and was told that I may want to to put leveling compound, which will NOT act as an underlayment, so I will have to put cement board on top of the compound. ...Well, which advice should I follow? :scratch:

I'm guessing I will have to take some kind of measurements to determine if the high and low spots exceed the requirements, but I have no idea where and how to take measurements.
Sorry that my first question seems so dumb compared to other people's questions, but I appreciate any help and suggestions.

Sponsored Links

03-06-2007, 01:47 PM
Is to get as much information to the people here on this site such as:
1. How is the floor framed (joist sizes, spacing, directions)
2. Get a string out and anchor it at one end of the floor, then run it to the other end and pull it very tight. Look and see how flat your floor. Do this in both directions, and at each floor joist. It takes time, but is well worth the effort.
3. let us know what type of flooring is going on there. Is it ceramic, stone, slate, etc. size and thickness is needed.
4. The floor does not have to be level (but it helps). It does need to be as flat as possible though.

03-06-2007, 02:49 PM
Thank you so much for your quick response.
I'm sorry that I have to answer some of your question with additional questions..

1. How can I tell the size of joists, spacing, and directions over the subfloor? I am guessing there is a beam under where the board is nailed, but I cannot tell its size...
2. When I place a string on the floor, do I have to take any measurements (distance from the floor, etc)? If so, what is the proper way of doing this...? Since I don't know where the joists are, I don't really know where to anchor it.
I did try to put a carpenter's level across the floor, and I know it's definitely not level in the middle section of the bathroom.
3. I was considering to install porcelain tiles until I learned porcelain tiles are very tricky to cut. (This is another question I was going to ask.) If that is the case, I will go for ceramic tile. The tile I was going to purchase was made of porcelain (about 1/8" thickness), but I haven't looked for any ceramic tiles yet. I am not considering stone or slate.
4. The thought of pouring compound over the subfloor scars me, so I'm a bit hesitant about it... It is great news if I can jsut use mortar and cement board and not use any leveling compound at all...

Scottish Tile and Stone
03-06-2007, 03:03 PM
Tama. is there a way to see the underside of your bathroom? Or maybe there is a vent where you can see what type of plywood and how many layers are there? As far as leveling before hand. If your not setting stone, I would level the tile as I go. Once you figure out what type of flooring construction you have. You might have to add another layer of plywood. Then you will want to put down some CBU. That will be embedded into a premium dry mortar. You will have to mix the mortar in a bucket. DO NOT USE ANY PREMIX ANYWHERE IN YOUR BATHROOM. You will need to get some alkaline resistant mesh tape for the seams. Its easier to flash the seams over with thinset and tape while your setting the tile. Less chance to leave a big bump in the floor.

Then while your setting the tile, use a 4' and maybe a 6' straight edge or level to set with. You might have to back butter a few tiles to keep them somewhat flat. If your floor rolls abit thats fine, just try to keep the tile lippage to a minimum. Take your time, and it will look awesome.

Did any of that make sense? :wave:

03-06-2007, 03:52 PM
Hi Scott, thank you for your response.

There is an open space where the pipes are, so I took a picture.
There seems to be only one layer of plywood (although I don't know what type), and the thickness is 3/4". Will this be enough information to determine if I need to add another layer of plywood or not?

>Then you will want to put down some CBU. That will be embedded into a premium dry mortar. You will have to mix the mortar in a bucket. DO NOT USE ANY PREMIX ANYWHERE IN YOUR BATHROOM. You will need to get some alkaline resistant mesh tape for the seams.

I got this part.

>Its easier to flash the seams over with thinset and tape while your setting the tile. Less chance to leave a big bump in the floor.

But I didn't quite understand this part... I was told by the tile installer that, if I am going to use CBU, I should lay tiles alongside the seam so that the tile will not break due to the height difference... My understanding of your suggestion is to lay tiles over the seams, is this correct?

Sorry for all of these small questions, this is all new to me but I'm trying. :tigers:

03-06-2007, 04:03 PM
... I was told by the tile installer that, if I am going to use CBU, I should lay tiles alongside the seam so that the tile will not break due to the height difference...

What height difference? :shrug: There shouldn't be a height difference in properly installed CBU. You need not be concerned about the CBU seams when you are laying out your tile.

In case it hasn't come up yet, when installing your CBU, avoid having 4 corners meet at a point. Stagger them. :tup1:

03-06-2007, 04:43 PM
Hi Dan, thank you for your response.

Yes, you're right about the height difference. There shouldn't be any if properly installed. I guess I was worried about the CBUs not being level if installed on an unlevel surface...

And yes, I was told about avoiding to have all 4 corners meeting at a point, so I will stagger them. Thank you for reminding me.

I took JohnP's suggestion and tried to put a string across the floor, but I didn't have anything to anchor it. Maybe I'll ask my husband to hold one end and try it again when he comes home tonight.
Meanwhile, I took out a carpenter's level (4') and laid it across the center of the floor. The distance from the surface is about 1/8" as you can see in the picture. I'll be getting ready to head to store to purchase CBU and dry mortar in the next few days, but if any of you think 1/8" is too much, please stop me here right now. :bow:

I have to rent a truck to carry 3x5 boards, so I will also be asking question about the wall boards (for tub surrounds) shortly (so I won't have to rent a truck again). Yes, I'm also planning to tile the tub surrounds me crazy.. :crazy:

03-06-2007, 11:49 PM
So, here's the picture of the tub-surround. I'd like to try to tile the tub surrounds myself; I will try the floor first, and if I find it too difficult to install tile, I might ask for professional help for the wall. But I still would like to prep the wall myself so that I can save some $.

I've removed the synthetic marble tub surrounds, and I now see the drywall and...I guess this is called "greenboard" or "sheetrock"(?).
Now..., my plan is to install tiles on exact same areas where the synthetic marble used to be (not all the way to the ceiling). (You can see caulking around the area where marble used to be, but the upper part is drywall, not greenboard.) I know I have to replace the greenboard, but do I also have to tear down the upper part of the drywall and replace it with new greenboard (or sheetrock) & place CBU on top of it? Or can I get just replace only the old green board, keep the existing drywall, and place CBU on top of it?

I hope my question makes sense to you.

Also, I'd appreciate if someone can tell me how to remove the old green board - it's nailed down to the beam behind it. Can I just yank off the wall...?

Thanks for your help!

03-07-2007, 06:36 AM
Yes, you can just yank it off. I tend to try and be a bit meticulus and cut down each side of the nails or screws, then when the big pieces are gone, I go back with a hammer/screwdriver and remove the nails/screws.

Regarding the string on the floor to just for dips, etc. I usually use screws. I put in a drywall screw into the floor, leaving about 1/2" above the floor, then take the string, tie a loop around the end, then pull it tight and drive the screw in. then I go to the other end of the floor and do the same, except, I loop the string around the screw a few tims, the drive the screw in.

Regarding your tile on the wall. Are you going to use Kerdi under it? You should read up on that if you are, as there are tons of folks here who have used it and can give tons of good advice.

Pour a cup of coffee and do some reading! :)

03-07-2007, 07:54 AM

Looking at the picture of your subfloor, maybe the picture is deceiving but I'm wondering if you have two layers of ply making up that 3/4" total, maybe one about 1/2" and one 1/4"? If so, it makes a difference.

If 1/8" over 4' is the worst wobble in your floor you shouldn't have any worries. Typically you tile a room in quadrants, starting each quadrant from the middle of the floor to minimize layout error. Having your high point there helps IMO because you can set those tiles tight to the floor and use a thicker layer of thinset (within reason) to make up the difference as you tile toward the walls.

I would advise against SLC (self-leveling compound.) First it has it's own tricks for proper installation and second, it will seek true level so if your floor is not flat (room corner to room corner) it will pile up in the low spots before flattening out over the rest of the floor. Again, your wobble looks pretty mild.

When you get ready to redo the walls for the tub surround make sure you read up on the proper way to install a vapor barrier and level/shim studs if necessary. Ask questions and post pictures first, then do the work. :yeah: Your life will be easier that that way! You'll get the help you need here.

Good luck!

Scottish Tile and Stone
03-07-2007, 11:20 AM
Rotozip or something similiar is the easiest way to cut out the drywall.

03-07-2007, 12:03 PM
:goodluck: Tama,

Just a quick note from another DIYer. You have what I believe is the hardest part of the project taken care of; you are willing to try, and obviously you're not afraid to get your hands dirty. I love to see people excited about projects, especially when they are willing to investigate, learn, and do it right! You've come to the right place. These guys/gals have been a huge help to me over the past few weeks!

Good job!


03-07-2007, 12:46 PM
Hi JohnP, thanks for your advice again! I will try to tear down the wall today, and I will also be sure to read the Kerdi topic.

Hi Mike, I was concerned when you mentioned there might be two layers on the subfloor - I didn't notice until you mentioned, but you're right, it does look like there might be two layers in the picture. I just went upstairs to check on the floor, but the opening is so small that I wasn't able to tell from the cross section if there're two layers. I am adding some more pics so that someone may be able to help me identify the layers better. Are there really two layers? If so, how does this affect my floor project?
(* There are 3 small holes for the pipes on my floor; the pics show cross section of the subfloor from three different holes.)

Everything else you said in the response made sense to me. Thank you for your advice.

Hi Scott, I've never heard of Rotozip before, but I will google it to find out what it looks like. There are so many great tools out there, and I get excited whenever I find new useful ones. Thanks!

Jim, thank you for wishing me good luck, because I NEED IT! :yeah: It took me a little courage to post a thread here, but I'm so glad I did. When I go to home improvement stores for help, I find two kinds of people: those who tell me I can do it, and those who look at me and tell me I should hire a pro (or have my husband do it, etc. :tongue: ) It feels good to find those who encourage me, so thank you. And yes, we came to the right place, didn't we? Thanks, everyone.

03-07-2007, 01:41 PM
That looks like one layer to me.

By the way, what camera are you using? Those pics are impressive.

03-07-2007, 02:17 PM
Looks like a single sheet of 5-ply board to moi. I'd like to see a thickness measurement at a clean, fresh cut, though. Not sure that's 3/4".

And the condition of your subflooring could not be listed as very good. When testing is done for tile products over wood subflooring, the materials and installation methods are all perfect, and still 3/4" plywood over 16" joist centers is near minimum specs. I would recommend you install another layer of plywood over what you have there.

My opinion; worth price charged.

03-07-2007, 04:38 PM
Dan, I'm glad to have someone confirm that it is one layer.
Regarding the camera, I'm using Casio Exilim 3.2mega pixel digital camera, which is about 4 years old now. I always use the maximum resolution when I take pictures, but I go back and trim off unnecessary parts so that it will be under 50kb. Hope this helps ;)

Dear cx,
I'd like to see a thickness measurement at a clean, fresh cut, though. Not sure that's 3/4".
How can I accomplish this? I guess I will have to make a cut somewhere in the subfloor...?
If I am to install another layer of plywood on top, what is the recommended thickness of the plywood? Pls let me know...thanks! to the store to look at rotozip... :p

Scottish Tile and Stone
03-07-2007, 05:00 PM
I would use a good plywood, at least 1/2" (not OSB), and screw it down. Try not hitting the floor joists.

03-07-2007, 07:32 PM
but do I also have to tear down the upper part of the drywall and replace it with new greenboard (or sheetrock)

Using a sharp utility knife or your new rotozip, cut the sheetrock an inch below the height of the new tile installation. Replace the lower sheetrock with CBU (and a vapor barrier) and when you install your new tiles, they will overlap the seam between new CBU and existing sheetrock. Makes a nice clean transition.

03-07-2007, 08:07 PM
You could just make a cut somewhere on the side of one of the existing holes, or drill a 1" hole with a paddle bit (carefully) and measure. If you're gonna add the half-inch plywood, it doesn't matter much what the actual thickness is, though. Well, 'cept for my curiosity, of course. :)

03-07-2007, 09:45 PM
Wow, I always learn new things here; OSB - I looked it up on the internet and learned what it was. I will be sure to ask for traditional 1/2" plywood. And I will be careful not to hit the joists. Thank you, Scott.

Alex, thanks for the very clear instruction on how to deal with the wall. I did get a rotozip today, so I can proceed to cut the wall tomorrow. (I'll spend some time reading the instructions tonight.)

cx - I guess I can use the rotozip I just bought today to make the cut. I have to check if I have appropriate attachment, but if I do, I will try to cut a small part tomorrow just to satisfy your curiosity :D

03-07-2007, 09:51 PM
Awwww, ain't you jest the sweetest thang? :o

03-08-2007, 07:27 AM
It looks like one layer to me as well. From the first picture I think you can see why I thought it might be two.

03-08-2007, 05:03 PM
I tried to use the rotozip to cut the subfloor this morning, but I'm not doing that well. The blade doesn't even put a dent on my floor. It's a long story, but the bottom line is I don't know how to use this thing (I hate to admit it). I will go back to the hardware store where I bought it, and ask them to show me how to use it right tomorrow. :shake:

In the meantime, I went back to the bathroom with a tape measure. I know you wanted to see a clean-cut cross section, but this is the best I've got.
The thickness seems to be 5/8"..., am I right?

I know you recommend that I add 1/2" plywood on top of this subfloor, but I also realize that I may not have enough depth to do that. (1/2" plywood + mortar + 1/2" CBU + thin set + tile = too high) I'd like to keep the bathroom floor as close to the height of the hallway as possible, so I may not be able to afford another 1/2" rise at this time.

Should I still add 1/2" plywood to be safe, or can I just install CBU on top if the existing subfloor?
The floor is sound; it doesn't bounce or squeak when I jump/walk, but I do see somewhat-crumbling pieces shown in the previous pictures (albeit only small section of the floor).

Your advice is always appreciated.

03-08-2007, 05:07 PM
If you're concerned about height, use 1/4" CBU. You wouldn't compromise anything by doing so.

03-08-2007, 05:09 PM
So you recommend that I still add 1/2" plywood?

03-08-2007, 05:12 PM
I recommend that you listen to CX. ;)

03-08-2007, 05:16 PM
OK Dan. Thanks for letting me know about the 1/4" CBU, that will make my life easier. :nod:

03-08-2007, 06:26 PM
Hi Tama,

I think the guys were saying you could use the rotozip to cut the sheetrock...not the plywood floor. A small rotozip doesn't have enough rpm I don't think. I have a large one that has the right hand angle tool attachment, the jigsaw attachment etc. I slapped a diamond dry blade on it and cut ceramic tiles! A little on the dangerous side, but it sure is nice.

I'm with you on the "doing rather than having someone else doing". I got really tired of folks at the hardware store saying something cute like "looks like your husband will be working this weekend!"

Especially since I've been divorced for 16 years! lol.

I like trying something and being led along with all the great help here, then standing back and looking at it then saying, "yes, I did that myself."

Just keep asking questions.

03-08-2007, 08:07 PM
Yeah, Tama, you really hafta add the plywood. The absolute minimum possible subflooring, under perfect test conditions, that can be made to pass the necessary testing is 5/8ths. And that's all you've got and it isn't new and it isn't perfect and it's not likely to have been perfectly installed with the necessary construction adhesive, etc......... Pewt some plywood. You'll feel better. :)

And you can not only use thinner CBU to reduce height if you want, but you could even go to a membrane like Ditra or NobleSeal to reduce it even further.

My opinion; worth price charged.

03-09-2007, 12:06 AM
Hi Linda :wave:
I was going to use the rotozip with a bit to cut through the drywall, but I thought I could also use the attached wheel blade to cut through the floor. I used the dry diamond zip wheel (yeah, I know it's for tiles & stones.., but I thought it might do the job). I guess I was wrong or didn't use it correctly. Mmm, lots to learn here.

I switched to the bit and tried it on the drywall, and oh my! :eek: - a few minutes later, the drywall almost caught on fire! (The tip of the bit turned black and smoke was coming from the wall.) I wasn't sure if it was supposed to do that, so I'd better go talk to the folks at the hardware store.

Ugh! You had the same experience at hardware stores. Fortunately, I got to know a few folks who are willing to enlighten me at the nearest store, so I now go to that store only.

And yes, I also get great help here. Wait and see until I upload my finished bathroom pictures,......well, maybe in 5 months or so. :yeah:
Thanks, Linda :)

cx - alright then. I will add a layer of plywood, 1/2" thick. I will look into Ditra and NobleSeal also. Forgive me, I'm asking without researching, but where do I get items such as Ditra, Kerdi rolls, etc.? I'm not sure if the local home improvement centers have them. (I haven't read the Kerdi book yet.)

Thank you all.

03-09-2007, 10:04 AM
Forgive me, I'm asking without researching, but where do I get items such as Ditra, Kerdi rolls, etc.? I'm not sure if the local home improvement centers have them. (I haven't read the Kerdi book yet.)Some Home Depot stores actually stock some Schluter products, but for most it seems to be a special order item. And if you hafta order it, it's a whole lot faster and easier to order from our friends at Tile ( Having special-ordered from Homer a time or two, you can't beat me hard enough to make me try to get Ditra or Kerdi there. I always order mine from Tile :)

[No, we don't make any money on Schluter sales through Tile, we just like his style :) ]

My opinion; worth price charged.

03-09-2007, 06:52 PM
I went back to the hardware store to get an instruction on how to use the rotozip. Yeah, I wasn't using it right; I just needed to have someone to show me how to use it. I came home and worked on the wall, and it works beautifully! (I also learned I wasn't using an appropriate wheel to cut a wood floor.)

So, the wall is almost torn down. I still have a small sections left, but I will work on it over the weekend.

Dear cx, I will definitely take a look at Tile - I did visit their site a few times, but I haven't seen products you've mentioned yet.
I will also read about Kerdi this weekend. Sorry, I'm moving so slowly that this project is taking forever.

1) I understand there are various sizes of plywood out there - should I get a reasonably large piece and cut it to fit the floor, or will several sheets of 3x5 do? The bathroom floor is 77" x 79".

03-09-2007, 07:36 PM
Top left corner of the Tile Experts site, scroll over where it says Products, you'll get drop-downs with all kinds of Schluter stuff.

You want to by two 4x8 sheets of plywood and cut to fit. You'll have a lot of extra, but you can build lotsa bird houses. You really want the new sheets to cover all the joints in the existing subflooring. That's part of the value of the second layer. And be sure to lay the new wood with the grain perpendicular to the joists, just like the layer you have.

And don't worry about the speed. You've got at least a couple more years before you can even think about entering the race for slowest project hereabouts. We got a number of three and four-year project owners who'll think you're not even a decent amateur at this point. :D

My opinion; worth price charged.

03-12-2007, 10:49 AM
I've placed an order for Ditra at tile experts :tup1:

I'm getting ready to rent a truck so that I can get some plywood, but I have a few questions:

1) Am I supposed to leave a gap between the wall & plywood? (I might have the shop to cut the wood for me, so I need to get the measurement.)
2) What about gaps between each plywood sheet?
3) Is it necessary leave the plywood in the bathroom a few days prior to installing to get it acclimated to the temp/humidity? Some books recommended it.

Thanks! :)

Re: 1) & 2), would 1/4" gap between each sheet & 1/2" at surrounding walls be appropriate? thank you...

03-13-2007, 01:02 PM
bringing it up to the top... somebody help me, please...

03-13-2007, 01:37 PM
You need only 1/8th between sheets and 1/4 at the perimeter is sufficient.

03-20-2007, 04:17 PM
I'm finally getting ready to install plywood underlayment and came up with another question.

How should I cut the plywood around this toilet flange?
I'm not sure if the plywood underlayment should be level with the top of the flange, or the flange should be above the underlayment.

I appreciate your advice. Thanks!

03-20-2007, 04:44 PM
The toilet flange is properly installed on top of the finished floor, Tama. That's on top of your tiles.

03-20-2007, 05:01 PM
Dear cx, thank you as always.

In that case I have to cut the plywood to fit around the pipe below the flange and then take this orange flange off the pipe to lay the ply (because the hole in the ply would be smaller than the flange).

Obviously I've never done this before, so I tried to yank the flange off the pipe, but it didn't budge. Have any idea how I can take the flange off? Is there a better way of laying the ply around the flange?

Sorry for asking so many basic questions, but I cannot find answers anywhere.

Thanks for your time and effort to answer my questions.

03-20-2007, 05:08 PM
You can split the piece of plywood for that area and install the halves under the flange if necessary. Or you can cut a piece to fit the area, cut the hole for the pipe, cut a wide notch in the plywood that will be behind the toilet, and slide it in from the front. Just depends upon how your pieces are laid out.

I don't know of any of those flanges that are removable without removing the whole fitting. Maybe others know differently. :)

We're here to answer questions. Don't worry about that part. Just worry that your source of answers isn't more diversified. :shades:

My opinion; worth price charged.

03-20-2007, 05:26 PM
I will most likely take the first suggestion and split the plywood.

My DITRA should be arriving anytime soon, so I'm sure more questions will follow. I will try to research myself as much as possible, though.

Thank you! :D

03-21-2007, 09:43 PM
I will be finishing my plywood underlayment installation by tomorrow :yipee:

Prior to installing DITRA, do I need to fill the gap between each plywood sheets?
If so, what kind of material is appropriate?

Thank you!

03-21-2007, 09:59 PM
Pay no attention to those gaps, Tama. Don't try to fill'em, don't try to keep'em clean. Just pretend they're not there.

My opinion; worth price charged.

03-21-2007, 10:03 PM
Yipee! One less job to do and one less thing to buy, and I'm loving it! :yeah:

03-23-2007, 01:17 PM
I'm cutting out the Ditra to fit the floor.

After installing 1/2" ply, there's no space to install Ditra under the toilet flange.
Can I just cut out the Ditra outside of the flange, or is it absolutely necessary to put it under the flange? I tried to fit it all morning, but it's not working.............................! :crap:

Brian in San Diego
03-23-2007, 01:28 PM
You do not have to get the ditra under the toilet flange. CX is telling the truth about the height of the flange being at the finished floor height and once you add tile, your's will be below the finished floor height. Same happened to me and I cheated and went to Lowe's and bought a toilet flange spacer kit. I also bought a Fluidmaster wax-free toilet bowl gasket. Might not be the 100% correct way to go, but saved some trouble in trying to replace the flange.


03-23-2007, 01:55 PM
Thank you, thank you :bow:

I might have a toilet flange spacer (bought it by mistake). It might become useful when it's time to set the toilet.

Thanks, again, Brian!

05-18-2007, 12:03 PM
I am back from travel and ready to install my bathroom floor tile. (Finally.)

I have a question about the amount of space I need to leave between tile & wall.

I have removed the existing base molding and am planning to install wainscoting with base rail/shoe after the floor is completed.

When I install floor tiles, should I leave 1/4" space between the wall, or should I leave enough space for the molding + add'l 1/4" space?

In other words, I'm wondering if molding should be installed on top of the floor tile or on the same level as tile.

I have already drawn reference lines but came up with the above question.
I'd appreciate if someone can give me a tip on handling this.

Also, is it necessary to complete the entire bathroom in one day, or can I work little by little? I'm unsure if I can finish the entire room in one day.


Brian in San Diego
05-18-2007, 12:25 PM

You need to leave only 1/4" between the tile and the wall. If it gets a little closer no big deal, but I think 1/8" should be your absolute minimum. I set my moulding on top of the tile after everything else was done. It hides the gap you leave between the floor and wall. The gap can be caulking necessary. Just be sure it's free of thinset, debris, etc.

Good news! You can tile at whatever pace you are comfortable with. Just make sure you only mix enough thinset you can use in 60-90 minutes. That becomes somewhat of an art. You don't want to keep throwing thinset out.