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!

[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?

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.

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!

[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.

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!