Installing Cement Backer Board

Question:

On one whole wall of our den, there is a brick fireplace/wall. (This is an outside wall.) Over a period of years, the brick has become covered with a white, grainy, substance that flakes off and is ruining the mantle and any pictures or items on the wall. (we have a couple of mounted deer heads and a nice mounted fish hanging on the brick.) The mineral substance is ruining the wooden plaques that they are mounted on.)

We would like to cover the brick with something like sheetrock, but the moisture would seep through, and also, it would not be fireproof. I am wondering if there is a way we could use cement board to cover the brick, and if it would be moisture and fire proof. Can you please advise me?

Actually, I have two questions that I really hope I can get assistance with. The first question is this, I am trying to level a concrete living room floor that drops a little over 1" in seven feet in one corner.

Has anyone ever used the self-leveling concrete, and how self-leveling is it? Is there much prep or post leveling work involved?

The second question is this, I have a plaster popcorn ceiling (circa 1975) with radiant heating coils in the ceiling. The coils do not work; and I want to get rid of the popcorn ceiling which might have asbestos and install recessed lighting. There is no attic. I live in a third floor condo unit.

What is the best way to get rid of the popcorn, and how?

Thank you for any assistance you can provide.

Chris Apmann

Chris,
You can buy excellent self-leveling compounds. USG has a new one I am dying to try on a job. Spray a small area of the ceiling with water. Mist it for several minutes. Use a flexible putty knife to scrape off the popcorn. If it was never painted, it will come off easily. Keep it wet to minimize any hazard from asbestos *if* it is present. To be 100% safe, take a sample of the popcorn and have it tested. It is easy to find one online.

Hi Tim,
I need to get the stain and crud off of my shower pan. It has the non-slip floor and I have tried various cleaners in the dimpled non-slip area with out results.
Thanks,
Bob Marks

Bob,
Please read *all* of my past columns about cleaning ceramic tile. You will discover a chemical in your kitchen pantry that will solve this pesky problem.

Due to the drain location in my basement cement floor, I am considering pouring a shower base consisting of concrete and tapering it toward the drain. In doing so, I can get the maximum size of my shower. Can I do this without water leaking through? or potential long term water problems between the floor and the base? How thick should the concrete shower base be? I was considering framing the shower and installing backerboard. ONce framed, I was going to pour cement approx 3 inches thick. Will this work?

Bob,
This will be a dismal failure. You need to read all of my past columns about Shower Pan Liners.

greetings,
My question for the craftsman is, can I lay hardy-backer board directly over linolieum as long as it is properly secured with backer board screws? Its regarding a bathroom floor that im going to tile. The house has a plywood sub-floor,est.1988, and the linolieum is smooth and flat. I hope this is enough info, I just want to do it right the first time so I thought I'd ask the builder!

thank-you for you time- sincerly,
Bob Tanner

Bob,
If there is no cushion under the sheet vinyl, then I say it is fine. But if you can depress the vinyl with your finger, then it must come up.

TIM;

IS IT NECESSARY TO INSTALL GREENBOARD BEHIND THE BACKERBOARD?

THANK YOU

Bob,
No.

My husband and I are building a house and we're tiling our showers. We have already put backerboard on the walls and cauked between the sheets. My husband purchased a rubbery material to roll onto the backerboard to waterproof it. Will this work alright? I'm worried that we've done this all wrong. Everything I read about says to put roofing felt between the backerboard and the studs. I'm also concerned on how the tile will stick if they are laid on top of this rubbery material instead of on the backerboard directly. Thanks!

Stephanie,
You are 100% correct. I would never attempt to put that on the walls. Now, maybe he brought home a crack-isolation membrane for floor tile......

I'm installing a new bathroom and when I installed the cement board some of it cracked as I was screwing it down. I believe it cracked because it was bowed a bit. Should I replace the boards that cracked? Or am I being over cautious?

Jim,
Cracked means to me that there are/were void spaces under the board. You need to fill these low spots.

I'm planning on remodeling my bathroom. How do I remove a 1955 laid ceramic tile from the floor? I'm not sure, but I believe the floor tiles are applied to the substrate using thickset since the same cermic tile on the walls of the bathroom stand out from the wall by about an inch or so (I observed this because the edge tile has a rather large bullnose). Can a thinset be applied directly over the existing ceramic tile on the floor and then enbed new ceramic tile in that?

Thanks for your help

Bob,
You remove that tile with great difficulty. There are organic mastics that allow you to tile over tile.

i plan to install a three piece whirlpool tub with tub surround would 1/2 inch cement backer board be best to put on the wall just behind the tub surround can i just put backer board up then tub surround on top

Brian,
I am not sure I understand you. Often you do not need to put anything behind the molded tub/shower surrounds. What do the instructions say to do?

I want to tile a small counter top in our laundry room,about 2ftx5ft. It has a formica counter top on it now, can I lay cement board directly on the formica or do I need to take the old counter top off and put new plywood on first then put the cement board on. Also is liqiud nails o.k. to use?
Thanks,
Greg.

Greg,
You can tile right on the laminate top if you desire. My guess is that it is structurally sound and the laminate will act as a grat waterproof membrane.

I plan to bring hardiebacker all the way to the ceiling in my bathroom. However, I am not tiling all the way to the ceiling. How do I finish the hardiebacker so I can apply texture/paint finish over it?

I am rebuilding a shower and have it down to the studs. I want to insulate the wall and also add a poly vapor barrier before installing cement board. Should I remove the paper vapor barrier on the insulation before I put up the plastic or is it ok to have both. Thanks

Robert,
You can skim coat it with a dry-setting type joint compound like Durabond 45. Read about these durable mixes in my Drywall category.

Jon,
It is fine to have both.

Is it necessary to apply mortar to the substrate before installing backerboard?

Mark,
Yes. The thinset ensures there are no air gaps under the board.

Dear tim,
i have a large kitchen with rather dowdy brown 6x6 tiles from floor to cieling, these tiles were on when i got the property which makes the kitchen very dark, i am thinking about selling the property but think this would put off potential buyers what would be the best thing i could do to brighten the place up and to update the kitchen without creating to much mess and cost,

Roy,
Paint them. Read all my columns about this.

Bob, we have a covered patio that isn't headed. We are planning on tiling it. It is a cement patio that I was thinking of putting Cementboard over it to make a level surface and then tiling it. is there anything special I should be doing to adhere the Cementboard to the old cement patio.

Jack

Jack,
I don't know who Bob is...... But I will jump in. Forget about cement board. You need to do a thin Concrete Overlay. I have many columns about how to do this to get the level surface you need. The columns are in my Concrete categories.

We recently put down brand new HardiBacker to our bathroom floor and were re-installing the toilet when a pipe came loose and water went on the floor. My husband had to run to the basement to shut off the water and in the mean time, some water pooled on the floor and I quickly tried to wipe it up. Around the toilet, screws, and some corners, the Backer still looks a little damp. However, it is drying rather quickly, do we need to take up all the wet Hardibacker and replace it with new before we lay our ceramic tile?

Ali,
You do not need to remove the board. Just let it dry. Also, the tile should go under the toilet, not butt up against it.

My floor is concrete with two layers of probably ten year old vinyl tile; the contractor laid down plywood and then laid ceramic tile on top. Should he have used cement board before the tile?

T,
Not really. Why didn't the new floor go right on top of the concrete?

Tim,
With regards to backerboard, can I use a roto zip tool, to cut out the profile for the sink.

Thanks

Bob,
Yesterday my grandson did something to push two 6x6 ceramic tiles through the wall that surrounds the bath tub. He doesn't know how that happened? After inspecting the damage I found that the rest of the wall was really weak. The walls have sheet rock behind the tiles and Im afraid that they are water damaged. When I replace them with new material, should I replace the sheet rock with the same material and then put the concrete backer board on top of that, or should I remove all the sheet rock around the tub and replace it all with the cement backer board.

Thanks
Jerry

We want to retile our shower surround. However, are confused about what to put behind the tile. We have been told to install a sheet of plastic first and then use "EASYBOARD". We noticed it says its for floors and counter tops. Its a 1/4" thick, super light, and can be cut with a utility knife. Is this correct or do we need to use something thicker or hevier to support our ceramic tile? Please help, we dont want to find out the hard way. If you can give the exact brand or name of the product, that would be helpful. We are getting material from our local Home Depot, so we are at the mercy of what they know and what we know!
Thanks
Heather Morris
elenahmorris@sbcglobal.net

I have a bit of confusion about installing backer board and needs some help. My story is that I'm working to remodel a 30 year old bathroom shower/tub stall. The bathroom itself is in great condition besides being very out of style. The existing walls have drywall with some type of backer board and then tile on top. So, here are my questions:

1) I'm assuming I'll need to strip the existing backer/drywall down to the studs. I've seen varying recommendations about whether or not there should be a drywall/greenboard between a vapor barrier and the backer board. Can you please explain why there are so many differing opinions and which route is superior? If it matters, the stall in question has one of three walls as an exterior wall.

2) At the edge of the shower/tub stall the wall transitions to a painted wall. The backer board or backer/drywall combo have a different thickness than the existing 5/8 drywall. Would the experts install an extra stud to force the backer to drywall transition to be located beneath the edge of the outermost tile?

3) As mentioned above, the backer board should have a 1/4" gap between the tub and backer board. Where does the bottom edge of the vapor barrier go?

4) Can you detail a method of measuring to ensure the walls are plumb? Is this simply running a 4' or so level over the surfaces to ensure constant contact?

Thanks for your help

Hello,
I am redoing our basement and already pulled up the old nasty carpet. I also scraped off the old pad. I'm left with the black adhesive that is practically bullet proof. I plan on installing tile in some of the basement and am wondering how I should get the old adhesive off. Some of the bags of mortar warn not to use adhesive remover because it will 'seep' into the pores of the concrete and affect mortar adherence. Is that true and if so, how do I get the old adhesive off? Can I use cement board right over the top of the old adhesive? If so, how do I anchor it into the concrete?
Thanks,
Jason

Joe,
You may be able to use that tool if you get the right bit. Wear the proper mask!! Silica dust is very toxic.

Jerry,
Bob was fired. We found out he really didn't have any real hands-on experience after all these years of being in front of the camera. :-> So I will have to answer this for you. Take off the tile and remove the old gypsum board. Install new cement backerboard or one that has a gypsum core that is 100% waterproof. Then tile.

Heather,
You can use any cement board that is one-half-inch thick. Durock is a good one. Hardiebacker is another.

Is it necessary to remove the toilet prior to laying backerboard and ceramic tile in a bathroom?

Tyler,
I would......

Jason,
Read my columns about Adhesive Removers.

I am installing a rough slag stone around the fire place and going all the way up to the ceiling would 1/4" hardibacker cementboard be strong enough to hold the weight or should I be using 1/2".

Brandon.
I would use the thicker material.

In the process of renovating master bath, including subway tiles on tub walls installed on Wonderboard, and after grout (but before sealed) discovered white tiles are discolored. Some are bright white, others just white, and some almost grey. How difficult is it to remove from and replace tiles on the cement board, and will I have to replace cement board as well. Thanks.

Bill,
It is not easy........ Good luck and next time watch those batch numbers.

That's the problem-- the batch numbers did match. The problem appears to be that the glaze on the tile was defective: looked beautiful on the on the new cememt board until grouted. When grouted, the grout appears to have penetrated the tiles, discoloring the tiles, which is why some remain bright white and others gray. The issue is whether we can simply take down the tiles and replace, or do we need to replace the cememt board as well. Thanks.

Bill,
It is time to get the tile factory rep out..... I sure hope you saved the boxes to prove the batch was the same for all.....

I am installing 1/4inch backerboard on a plywood bathroom floor. I forsee problems when I get to the toilet drain since it is screwed right on top of the plywood now. This means the height of the backerboard plus the tile will more than likely be level with or be above the toilet drain. Once I unscrew the toilet drain flange from the plywood and if there is not enough "play" to raise it up, what do I do? Does someone make an extender flange or something to fix this height issue. Thanks for the help.

We removed old tile from shower above bathtub. The wall under is plaster. Can we apply cement backer board directly on plaster or do we need to take wall out and apply on studs.

David,
There are flange extenders. Be sure to seal well between the flanges.

Sue,
You can install cement board on top of plaster. But keep in mind that you will have to deal with a transition. The cement board is supposed to be in the same plane as the finished wall.

I am developing my basement and i want to add a bathroom on it, i want to know which comes first the osb board or the cement backer board, can i screw them both on the floor.

We are in the process of finishing our basement. Our concrete floor is heated, so we can't (or shouldn't) attempt to nail/screw anything into it. We are installing an engineered wood over most of it which requires a 3/4 inch plywood subfloor. We want to use ceramic tile on the remainder of the floor and want to raise the floor to match the height of the wood. I thought we could use cement backer board, laying it over the concrete, but everything I've read strongly suggests anchoring it to the floor with screws... What other options do we have for securing the backer board to the concrete?

My questions is: I have a 3 story house and currenty have a front loader washing machine on the third floor which i am unable because of the sub flooring be just plywood with cover of vinyl. Now i was told that if i use two sheet of backer board one screwed to the floor and the other screwed to the backer board and the floor this would allow me to use my front loading washing machine. If i do this is there any suggestions of how to make it look nice i don't want to tile or put vinyl on the backer board. However, i do want to do something to proctect and prevent dust, etc. What would you suggest that cover the backer board with? Thank you ...Carolyn

When we moved into our house, the original floor in the kitchen is hardwood. We layed plywood and just put the cheap sticky tiles on top of that. Now, we've had some water damage and want to go back in with ceramic tile. One contractor said we need to leave the plywood, then lay hardy backer and then the tile. Another contractor has told us we don't need the plywood, just the hardy backer and tile. Can you help and let me know which way we need to go. Thanks

I am wanting to tile a screened in porch.
Joist are on 16" centers covered by 1 x 6 pressure treated boards. My idea is to lay 6 mill plastic then screw the backer board 6 to 8" center. Then tape the joints and apply thin set mortar on the tape lines before laying any tile. Is this sufficient or should I forget the plastic and and glue the backer board to the 1 x 6 boards and also screw? I like the idea of the vapor barrier since this is outside.

I removed some carpet at a landing of a stairway, and would like to tile that area. The carpet would end up thicker than the tile I am laying, so the local hardware store suggested using Hardiebacker Cement Board to raise the tiles first. I just wonder if I can use a regular All Purpose Construction adhesive to lacker the backer board to the vinyl tile subfloor instead of the suggested thinset. The subfloor is pretty flat.

Thank you for your comments.

To help stiffen the wall around my tub I used OSB board..can I screw backerboard directly to that and then apply my wall tile? If so, should I put on a vapor barrier first?

Arnie,
You better make sure the OSB will never get wet or damp.

I want to do a ceramic tile tub surround but I have cement block walls with a plaster finish. What is the best way to attach backerboard to the walls? Please provide as much details as possible...thanks!

I have found a brick and mortar chimney buried under my kitchen wall upon a recent renovation. This chimney is next to our gas stove and oven. I am incorporating it into my decor-scheme now. My concern is grease or other foods splashing on it over time. So to prevent such potential penetrating stains, what do you recommend for this issue? Some sort of sealant? Keep in mind... I don't want the brick to be glossy, nor have a sheen, nor any discoloring.
Your recommendations?

Thank you for this column, and several helpful comments. You say that before putting cement backerboard on a wall, the studs have to be perfectly plumb. My question is, essentially, how plumb is plumb?

I'm hanging the backerboard in the shower today, and it wasn't long before I discovered that our walls are not "square." So, I'm shimming studs to try to make the enclosure as square as possible. But now I find that in the top and bottom corners, the backerboard has a tendency to bulge. The worst bulge is in the upper right corner of the back wall. The top is a good 1/8" bulged relative to the mid point of that wall. When I noticed this, I started checking everywhere and found that there is quite a bit of variation in the topography of the backerboard, probably less than 1/8" elsewhere, but noticeable when you look for it.

I checked the tiled shower enclosure in the other bath, and found that there too there is a tendency for the walls to bulge toward the bottom. I had never noticed this before, but the variation seems to be less than what I am finding in the new enclosure.

I'm wondering, is it possible to level out some of this variation in the tile-laying process? Or should I pull it all down and start over? Thanks for any thoughts.

Tim, I am redoing the floor in our master bathroom. I have removed the old ceramic tile which was installed over cement backer board. I am wondering if I can install the new tile over the existing cement board if I skim coat the old thinset to level it out. Am I asking for trouble or should I rip everything out ans start fresh. The quality of the board is good.

Thanks!

I'm about to tile for a back-splash in the kitchen. My issue is space. I have little space to be able to used 1/2 inch backer plus the room for tile Due to stove size limit, etc.). Also at this time I have new counter tops soon to be installed. Obviously I want that first before preceding to the back splash. But do I make room somehow, for 1/2 inch backer for areas that can take that, and only place 1/4 inch on adjacent walls where absolutely needed?

P.S. Sorry about that Brick and mortar question. I didn't meant to hijack this thread (off topic). BTW, that's one area (reason) for the lack of space for 1/2 inch backer. Hard to move that thing you know! ;)

I am putting up cement backer board over studs with a vapor barrier in between. I would like to put up T & G cedar over the backer board in one area. I assume I can nail the cedar to the backer board without any problem since I am nailing the backber board to the studs. I am concerned, however, that the cedar will let too much moisture behind it. Do you think this will be a problem.

I would like to have what looks like a concrete wall in a new addition, but don't want a solid concrete wall. Can I use concrete board rather than dry wall and then cover it with concrete? If not, any other suggestions?
Thanks much.

Hello,

I have 1/2" durock subfloor but need to raise the floor by 1/4". I would like to use 1/4" moisture proof backerboard on top for added strength, but I am afraid thinset won't properly dry between the sheets. Can you recommend an appropriate adhesive for this type of application? Thanks!

Any thoughts on Schluter-DITRA? Is it a viable alternative to cementboard? In floors and/or walls? Thanks!

Hi Tim,
I live in a 1906 duplex with a plaster-over-brick wall that divides the units. I am planning to remodel my bathroom and want to tile the three walls of the alcove bathtub. One of the three walls is the brick dividing wall. Can I install cement board onto this wall and if so, how? I am also planning on replacing the plaster-over-lathe on the walls with new sheetrock but what do I do with the wall that is just plaster over brick? Thanks for your help!

I am doing subway tile halfway up the wall in the masterbath in a complete remodel, which I have stripped down to the wooden framing. How do you deal with where the cement board and the greenboard will meet?

A big Howdy from Texas

I am about to lay tile on my backer board I just installed on my subfloor. I am on pier and beam and the subfloor was in great shape. My problem is at each seam when I dry lay the 18 inch tile there is a little wiggle in the tile when layed dry. Will the thin set help level this out or do I need to level the seams?

Also when I screwed in the screws into the backer board the screws did not go completely into the backer board. They are not perfectly flush but they are close. Do I need to worry about this or will the thin set take care of this?

I am installing ceramic tile on my bath/shower walls. Currently, there is drywall on the studs. I was going to put a vapor barrier on top of the dry wall and then 1/4" Hardy-Board, then the tile. Is this good way to it?

I just took out a bath shower fiberglass insert and want to replace with a tub and tile the walls.

Do I need to install the backerboard first or the tub and then put the backerboard on?

Thanks,

Larry

Tim?
Are you there?

I want to install tile or hardwood flooring in my dining room. I also want to paint the walls in my dining room. My first problem is that the concrete floor has dips and sharp concrete projections in some areas. It is also cracked in some places. I don't know how to treat the floor before tiling/wood flooring it. Do I remove the molding first? Should I paint first then do the floor or does it not matter?
How do I make sure the floor is level? Thanks

hi im want to tile my kitchen floor.in a house trailer.it has vinyl now do i have to put backer board first are can i tile on top of it.

I am installing a glass tile backsplash in a relative small area (14 sq ft)that is currently drywalled and painted. Can I use a crack suppression membrane or should I use backer board? Can I install the backerboard over the drywall?

Thank you.

I am putting ceramic tile down on a 14 x 14 ft floor. It had the sticky back with cushiony feel tile. I covered that with 1/8 in plyboard for the roughness, then used thinset (which quickly became thick) to install wonderboard backerboard over the floor. I fillied in all gaps between the boards and tried screwing them down, but the screws went right through the boards! They were the screws that came with the board. Now since this was done at about 3 am, I couldn't get more screws at that time. Am I screwed? I still need to screw these things down before going on to the next step. BTW, the floor feels nice to walk on, except in some of the corners of the boards.

I am hoping to get some help with a cosmetic issue:

I have installed backerboard in a standard tub surround in preparation for tiling. When looking at the back right corner, where the side wall meets the back wall, from floor to ceiling, I have checked the plumb of the right side wall by using a cripple with a 4 foot level. What I found is that the side wall is out of plumb by between 3/8 and 1/2 inch from floor to ceiling. This means that I have an ever widening gap for tiles as they are added to that corner beginning on top o the tub. I know that I will begin tiling in the middle of the back wall working outward and when I reach the sidewall, I will be cutting each tile to fit, so that at least the grout line won't get any larger, but I would like your opinion - do you think the gradual taper of the wall will be noticable when the tiling is complete, or would you stop any progress on tiling and replumb the surface of the wall before proceeding? Really looking for input from someone knowledgeable about what the potential outcome might look like. Basically, do you think anyone will notice, or will it look horrendous??

Thank you for your help...

Quick question for the experts:

Having installed backer board, if it is found to be out-of-plumb, can something like a floor leveling compound be used on the surface of the backerboard, skim coated, to replumb the surface or is that a no-no?

thank you for your help....

I am wanting to install ceramic tile over concrete flooring and want to install backerboard in order to make sure the tile has a level surface and also to keep it from shifting if the house shifts. Is this possible?? How do you attach backboard to the concrete? Thanks much!

Installing Ceramic tile in a 6 year ols house. After removing carpet the plywood subfloor is in gfreat shape. This is not an area that will receive alot of traffic nor water. Do I still need backer board or can the tile be laid diectly on the plywood floor

Hi I am currentlty remodeling my bathroom and in the process of getting estimates. For the shower walls, one of the contractors said he would install denshield over the studs then cement board, then tile over that. The other contractor will install only the cement board over the studs the tile. Which one is a) correct b)better, and c) is it overkill to have denshield and cement board?
Thanks

I used a silicone caulk between the seams in the hardi-backer board for my shower wall as suggested in the ask the builder web page. I am now ready to install tile on the shower wall. How do I mask / apply joint tape over the silicone caulking. None of the masking agents that I have seen (thinset to be used to apply the tile) seem to go over the silicone. Is there something special that I need to use - or do I need to remove the silicone caulk from between the joints?

I am installing durock cement backer board as a substrate for a shower tile surround. Do you place the tile on the rough side or the smooth side of the backer backer board?

Sergio

I am trying to replace stone hearth with glass tiles. Can I use this cement board to level surface for tile. Are cement boards fireproof and can sustain heat of fireplace.

Can backer board be put over library grade capeting which is already on 3/4" pylwood over cement before laying porcelain tiles?

can you use slate tiles on Hardibacker Cement Board or is Wonderboard better? This is for two shower walls.

thank you.
mau

Tim,

My question is the same. Do I need greenboard under my backerboard, or can I go directly to the studs, as long as I make sure it is straight?

Thanks,
Eric

backer board and ceramic tile installation

hi there im having my bathroom floor tiled and my tiler has asked me to place 6mm plywood over floorboards which i have done before he tiles.the squeeking is driving me crazy,was not there before i put plywood down.any tips to help with creeking noise.many thanks

Good morning:

I am in the process of installing a level entry shower in place of a fiberglass tub unit. I have obtained and followed your advice in in two of your E-Books, "Leak-Proof Shower Floors" and "Shower Pan Cement Mud Floor Installation". Both have been very helpful since I am only a carpenter. I am now installing cement backer board on the shower walls and bath floor. I have been advised to use two coats of a product called "RedGuard", a waterproofing & crack prevention membrane. Is this a good idea? Should I use it on the final layer of the shower mud floor as well?
Also, I want to pitch the bath floor toward the shower. How do I do this using cement backer board?

Would like to install ceramic tile in a second floor condo with wood subfloor covered by vinyal. Want to use a noise suppression material convered by durarock or cement board. Does the vinyal have to be removed? Do you simply lay or affix the noise suppression material on the vinyal? What thickness of cement board is sufficient?

I accidentally painted some of my cement board with a flat latex paint. Now my tile installer will not warranty his work because he says that the adhesive will not bond properly because of the paint. Is that true?

I've installed cement board on a shower wall and was told to leave an inch between the board and the poured shower pan to prevent wicking. After completing the pan pour the resulting gap seems too large. How can I fill this gap as i install ceramic tile?