Brick fireplace remodel finally underway!

[dfulmer]

I want to add a tile surround to my 1970's brick fireplace and tile the brick hearth as well. The entire wall is made out of real, recycled brick and the hearth is made out of real, recycled brick as well and runs along the entire wall. The hearth is not real flat on top. I'd have to measure the variance, but I'd guess it varies by 1/4" or so in height in spots.

Should I add backerboard to the hearth before I set my tile? What thickness (brand?) backerboard should I use? Do I need to sandwich several layers to build up the thickness? What type of thinset do I use?

Should I add backerboard for my fireplace surround as well? The wall is flatter than the hearth. What thickness (brand?) backerboard should I use? What type of thinset do I use?

Should I tile the hearth first and then the surround?

I like a stone tile look. What is a good (not outrageously expensive) tile to use for this project? Do I need to seal it before I set it?

Also, do I have to tape and apply thinset to all of the joints in the backerboard? I'm concerned about making sure everything I use is heat-resistant for this application.

Thanks for your help!

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[John Bridge]

Hi D, Welcome aboard. Please give us a first name. :)

I would suggest not using backer board at all. You might want to consider using a "medium bed mortar." Home Depot sells a Marble and Granite mortar that will work in this instance. It's a bit pricey, but it will do the job and save you the cost and labor of the backer board. Others may have different opinions. It happens around here. ;)

Oh, one other thing, back in the seventies (and I hope still) the bricks were called "used bricks." ;)

[bbcamp]

John, considering that they are used bricks, shouldn't lathe and a scratch coat be applied first?

[dfulmer]

Hi, everyone. My name is David, and I'm a pretty experienced do-it-yourselfer, but this will be my first tiling job ever, and I'm a little apprehensive about it. However, I've been looking at that ugly fireplace with the used bricks for too long now.

If it makes a difference on how to tackle the job, the hearth has bricks on top that overhang the vertical face of the hearth. The vertical face, if memory serves me, is three bricks high, and the horizontal top of the hearth is two bricks deep, with the top bricks set perpendicular to the wall. The top bricks overhang the vertical face about 1-1/2" to 2" (I didn't measure the overhang but it's a consistent overhang). I want to eliminate this overhang and have a flush vertical face. Would a medium bed mortar still be appropriate to build up a vertical surface in this case? Would I have to screed the vertical face and horizontal top of the hearth with this medium bed mortar? :bow:

[Unregistered]

David,

If you like the stone tile look you might also want to consider stone veneer. Check out:

www.eldoradostone.com

Lenny

[John Bridge]

Bob,

Used bricks usually just have old mortar on them. It's masonry, man. Mud. :D

Hi David. I would break the overhang off -- use a flat cold chisel and a big hammer. Or . . . attach peices of concrete block to the front of the hearth to fur it out. An inch and a half is too much for any type of mortar alone.

You could float regular mortar (fat mud) directly over the bricks. You will still need to build out with something on the front of the hearth if you don't break the overhang off.

[thevillageinn]

why not add some wood furring strips to bring the vertical face out the desired amount (minus the thickness of some backerboard) and then add backerboard, to provide a nice clean (no old mortar, or paint, or soot) surface for tiling?

attaching things to brick & mortar isn't too bad with a masonry bit and some anchors

[dfulmer]

The brick hearth runs the entire length of the brick wall, about 12 feet. I think building out will be much quicker than breaking off 12 feet of overhang.

What type of mortar would I set the cement block in to build out the vertical surface?

I was thinking of using 1/4" hardibacker on the rough top of the hearth and on the vertical surface as well. I think I'd have a better chance of getting a flat surface that way rather than using a medium bed mortar or such by itself since I'm a novice.

Is this approach all right? What type of mortar would I use to set the 1/4" hardibacker?

Thanks!

[dfulmer]

Oops, I meant concrete block instead of cement block! :bow:

[bbcamp]

To bond the cement blocks to the brick, use Mason's Mix. It is a mix of sand, portland cement and lime. It is sold ready-mixed. The Sackcrete brand is in a green bag.

If you want it install backerboard, you need to screw it onto the brick hearth using concrete screws (Tapcons). Bed the backerboard in some of the Mason's mix or thinset for support. However, you still may not get the flat, square surface you are looking for, since the backerboard will conform to some of the surface irregularity. Try using masons mix (fat mud) and a long straight board to screed the surface. You can temporarily attach wood forms to either end of the hearth to guide the board.

[dfulmer]

Is it really necessary to screw the backerboard to the brick hearth? Won't the thinset or other mortar be sufficient? Seems like wearing a belt with suspenders. :)

[John Bridge]

Sorry. I'm a mud man. Straight, flat, plumb and level are qualities that are pounded into our heads at birth. :D

As Bob mentioned, you won't be able to get everything smooth and straight or plumb or flat by applying quarter-inch backer board over the bricks. Dan's idea of furring out with sticks has merit, but it will entail buiding everything out an inch or so before adding the tile. It also consumes a lot of material.

Finally, there is no cement backer board manufacturer that specifies attaching the board with anything other than mechanical fasteners, either nails or screws. The mortar that is used under the board is simply to fill voids.

Finally, finally, if you are going to fur the fireplace out, you can use sheetrock to attach the tiles to instead of cement backer board. Sheetrock is considered a fire retardant, and it is approved as a tile substrate in dry areas. :)

[dfulmer]

I measured how much the top bricks overhang the vertical surface of my brick hearth. It's no more than 1". Can I float mortar over the vertical surface to make a flush vertical surface? What kind of mortar should I use?

A tiling book that I read said that I should first brush on latex-modified thinset onto the brick surface and while the thinset is still wet, float on the mortar. Do I need to do this?

Do I need to provide a perimeter joint between the mortar bed of the brick hearth and the drywall side walls? Is 1/4" fine?

Thanks! :)

[John Bridge]

You can use brick mortar to plaster up the vertical surface. The thin set skim coat is a good idea.

You will have to do your mortar on two separate days. You can only apply about a half inch at a time. :)

[dfulmer]

Would the brick mortar you refer to be something like "Sakrete Mortar Mix"? I saw there's also a "Sakrete Masons Mix" and wasn't sure which one would be better to plaster out the vertical brick surface of the hearth.

Should I also use a skim coat of thinset between the first and second 1/2" layers of brick mortar on the vertical surface or just between the brick and first layer?

Is it better to use a medium bed mortar rather than this brick mortar on the horizontal brick surface of the hearth? I need to level the horizontal surface about 1/4" or so.

Thanks for all of your help! I'm running out of questions so I guess there's no excuse for me not to begin this project!

:)

[John Bridge]

I'm not sure which of those products contains the most cement and lime. Buy the one that costs the most, and you'll get the better ingredients. You can also make your own mortar from masonry cement and sand.

Get the first coat of mortar on there as thick as you can without its falling off. Don't try to get it really smooth. After it has set an hour or two, "scratch" the surface with the notches of notched trowel or anything that will place a lot of small scratches in the surface of the mortar. The following day these scratches and ridges will grip the new mortar you will apply. The second coat must be smoothed off before it completely sets.

Not to toot my own horn here, but both my books contain pretty good instructions on doing mud work. :) You might find the first book in the library. :)

[dfulmer]

John, Thanks for all of your help. Keep on tooting your horn, because it just made me order your book! :)

[John Bridge]

Yeah, you've made my day, David. I'll take Patti out to eat tonight. :D

Thanks.

[dfulmer]

My name is David and I posted back in June with some questions about remodeling my brick fireplace. Well, I finally got up the courage and made some real progress, even though my wife doesn't think so! :tongue:

I have a couple of more questions, but first a status report:

I recently furred out the brick wall with furring strips, added 3/4" exterior grade plywood strips as a nailing surface around the fireplace surround to attach a mantel that I will build later, and extended out the front vertical surface of the raised hearth so that I no longer have a brick overhang on it (I used 3/4" exterior grade plywood to build out the front vertical surface). I'll cover up the wall with drywall and add a tile surround around the fireplace opening and will also tile the raised hearth. I had to buy a rotary hammer for all of the drilling through brick I had to do, but it was worth it, since the tool's such a pleasure to use. I used "red head" anchors and construction adhesive to attach everything. I bought a chisel tip for the tool and used it to flatten many bricks that were sitting high on the wall and hearth so that the furring strips and plywood nailer strips would sit flush on the wall and so that the fireplace surround and top horizontal surface of the raised brick hearth would be relatively flat. It took a couple of hours of chiseling on these used bricks, but I now have a flat surface that just needs to be skim-coated with thinset.

My questions: Can I skim-coat with thinset the fireplace surround right up to the plywood nailer strips I have around the surround or should I provide some kind of "perimeter joint"? Can I also thinset right up to the plywood nailer strips when I'm ready to lay tile?

I'm going to screw backerboard on top of the 3/4" exterior grade plywood on the front vertical surface of the raised hearth (to "bury" the brick ledge above the plywood, which is now flush with the plywood surface). Do I need to use thinset between the plywood and the backerboard on this "wall" application or are just screws sufficient? If I need to use thinset, should it be modified or unmodified? Should I also tape the joint where the vertical backerboard meets the top horizontal surface of the hearth?

Thanks for any help! :)

[Mike2]

Hi David:

I'm going to merge this recent post of yours with your initial thread from June so we can keep everything together - all that background information really helps all the moderators pick up where you left off.

Back in June the recommendations were along the lines of attaching expanded metal lath along with bed of fat mud on the vertical brick surround. Sounds to me like you are doing something different now asking about skim-coating the brick with thinset. That true?

[dfulmer]

Yes, the surface is relatively flat now and I skim-coated a little area to test the idea and it should work out fine.

[Mike2]

Anyway you could post some pictures David? That would sure help us to move you forward on this project.

[tmarie]

Pictures, please!! I am tackling a very near future fireplace redo myself. Being a more visual learner, pictures would be great!! Thanks!!

[dfulmer]

Here are two pics of my brick fireplace remodel. I don't have a digital camera, so I've made more progress than these photos show. This is my first time attaching pics so if they don't appear can someone help me?

I've already attached to the front vertical surface of the raised brick hearth 3/4" exterior grade plywood using modified thinset adhesive (I hope this was the correct thinset to use) and masonry anchors ("red heads") to eliminate the 3/4" brick ledge overhang.

I'm planning to nail cement backerboard (Hardibacker) on top of the 3/4" exterior grade plywood on the front vertical surface of the raised hearth to "bury" the brick ledge that's above the plywood, which is now flush with the plywood surface.

Do I need to use thinset between the plywood and the backerboard on this "wall" application or are just nails sufficient? If I need to use thinset, should it be modified or unmodified? Should I also tape the joint where the vertical backerboard will meet the top horizontal surface of the hearth?

Thanks!

[Mike2]

Hi Doug.

On a vertical wall (as opposed to a floor), CBU over plywood, I don't know if thinset would be considered a requirement. Prolly not but I'd do it anyway. A dry-set (unmodified) approved for use over plywood would be fine, like Master Blend. If modified is what you have, that will work too. Tape the seams.

What I don't know and cannot comment on is local fire code restrictions, if any, using a combustible product (plywood) on the face of the hearth. Just don't know.

[dfulmer]

I'm finally, finally ready to lay tile on my formerly brick fireplace surround and raised hearth extension. :yipee: I screeded on a mud bed on both surfaces and now they're both smooth and flat.

Should I tile the surround first and then the raised hearth extension or doesn't it matter?

Should the tiles on top of the raised hearth extension overlap (cover) the top edges of the tiles on front of the raised hearth extension or is it the other way around? What's the reasoning behind the answer?

Likewise, when I tile the fireplace surround, I also want to tile the narrow faces of the two vertical sides of the fireplace opening. I think these faces are about 4" wide. Should the tiles on front of the fireplace surround overlap (cover) the edges of the tiles on these side faces or is it the other way around?

Thanks for all of the help I've received on this project! It's been more challenging than I thought! :crazy: :crazy:

[John Bridge]

Hi David, :)

On the hearth I would let the horizontal tiles overlab the vertical. On walls you want to hide the joint as much as possible, so facing the fireplace, those tiles should overlab the others.