Hearth extension - can I put concrete backer board over concrete hearth + subfloor?

[breathebeast]

Yeah, can you tell I'm trying to save the use of the bullnose tile that should come in today, because I'd love to get the woodstove installed?!? (Though I suppose they can install the wood stove even if the hearth edging isn't finished, now that I think about it.) The current tile plan has a contrasting color (black) bullnose edging tile, too, so doing a bevel-edge wood frame seems like overkill (basically two frames for the space - though my staff is arguing that it will be better that way!). The reason for the contrast color tile was that the primary tile color looks great, but not when it's right next to the rather golden wood floor. Those two reasons are why I haven't gravitated right to the wood framing solution. Though originally I was worried about the difficulty in matching wood color anyway.

But I'd rather do it in a way that I have no regrets about...and this has been consistently recommended! Where do I find someone to talk to about wood framing? The only wood workers I'm aware of are cabinet makers and high end furniture makers.

 

[begreen]

A cabinet maker or a good flooring person with custom woodworking skills can do this. But also speak to a good tile person. There may be a specialty edge tile that might work? Doesn't hurt to ask. If you do decide to go with the wood floor beveled frame, it can be done afterward. It's all custom fitting at that point.

 

[breathebeast]

Thanks, BeGreen. Would we have to be able to cut out extra flooring to accommodate the bevelled wood edging? Or does it get nailed down over the existing floor?

 

[begreen]

Both are options, but for the most finished custom look I think it should be put on the sub-floor so that it matches the finished floor height on one side and the tile height on the hearth side. The gap for the frame can be any width you want it to be. It all depends on the look you want. The bevel piece can match the flooring or it can be from a different color wood entirely depending on the look desired. For example, if you had a dark tile border, maybe an ebony frame would set it off nicely.

 

[breathebeast]

Crap. I did something really stupid. It's an example of a little knowledge can be a bad thing! I read that the thinset was only good for 1/4" thickness, and I had that 1/2" inch wide gap between the old concrete hearth and the area I filled in with the micore and concrete backer board. So, read some more...concrete might not bond well to the surrounding substances...the tile guys seemed really keen on self-leveling concrete, and there were two posts on here where it was used, so I figured it was okay. Alright, then - found some self-leveling compound, slapped it in there. Covered the concrete hearth with medium set mortar to level it with the surrounding concrete board (already had decided I didn't like the looks of the self-leveling compound). Covered that with thinset and tiles.

And then my niggling doubts got louder, and louder...so I belatedly emailed Henry the company that makes the self-leveling compound, and they said they couldn't recommend it for a hearth. I want to call and talk with someone about the specific situation tomorrow and see what they say. I'm worried about whether it would outgas, too. If I do start over, I'll be finding some way to take the tiles off (and back here for advice on that!), removing mortar, finding the screws(lots of them, with thinset in them!) and removing the concrete board and the micore, chiselling out the self-leveling compound, and then starting over (might be worth renting an SDS drill...). A lot of work, but I'd rather do that over the next month than worry about it every time we use the wood stove, so it would be worth it (besides making my man fit-to-be-tied because he's doing so much childcare!).

Any thoughts, experience?

 

[breathebeast]

Hurrah, good news! While chatting with a DIY neighbor, I realized I had excluded something critical: the self-leveling compound was placed beyond the required dimensions of the hearth. So, something to mention to anyone who might purchase after us, but the temps there should be safe for any compound I'd put on wood flooring. Thank the gods. Especially since it appears no one else has had the pleasure of this particular goof and lived to tell the story!

 

[CarbonNeutral]

I wouldn't have worried about any outgassing - I would have just crossed my fingers - I think it would have been fine.

 

[KB007]

Do you have any option to raise the insert in the fireplace some to provide an air gap to the hearth? If you built it up on brick or concrete to create a raised install, your floor would only need to be "ember protection" according to the Regency manual "Thermal fl oor protection is not required if the
unit is raised 3.5" minimum (measured from the bottom of the stove). However, standard ember fl oor protection is required. It will need to be a non-combustible material that covers 16" (406 mm) in the US and 18" (450 mm) in Canada to the front of the unit and 8" (200 mm) to the sides"

Then you could do a nice hearth extension using cement board and tiles out as far as you want. Just a thought...

 

[breathebeast]

Oh. My. God. Built the first fire tonight, and it is heavenly. My entire perception of winter has changed - I think it's my favorite season now! Sitting in a room with a flame-show and a cozy-warmth made me more settled and comfortable than I've been in ages...and now, with just embers in the firebox, it's pretty much just as good 'cause the 3 dogs are relaxed in ways that make them look like their bones are made of jelly, and the cat has decided he doesn't have anywhere else more important to go and is hanging out on the cedar chest with us - heaven! (Perhaps I was mistaken when I wrote my signature...the cat is closer to the fire than anyone else, and the husband is downstairs with the xbox!).

Oi, I really wanted to post back here with a picture of the whole set-up, but the camera appears to be dead, so that might have to wait a little longer. But I will say that I went with just caulk around the edge of the exposed cement board under the tiles, and it looks fine - only problem being that the dirt and dog hair builds up at the vertical edge FAST.

We put the woodstove in too fast for me to put a blocker plate in, but I'm hoping that next year when the chimney is cleaned maybe i can put one in then. Can't really tell how much heat we'll really get, as it's barely cold enough for a fire tonight - but an unexpected side effect already is that I want to walk the dogs LONGER on their night walk and get nice and cold so I can come warm up by the woodstove!!

 

[breathebeast]

The new beauty(s):

 

[Pods]

I know this is a few months after the fact, but am posting for future info seekers.

I'm in Southern Ct and currently finished the futile search for Micore. Most folks I spoke with never heard of it.
Most companies who carry it only sell wholesale in bulk, not in single sheets (Including EJ Davis).
Called the Micore suppliers, no luck, bulk only.
Called Masonry supply companies, no luck.
Called HVAC companies, no luck.
Called a handful of lumber yards and got lucky with one. West Haven Lumber was willing to order me a sheet.
I think the mark up was a bit much($50 4'x8'x1/2"), but still worth it for my needs.

I suppose I could have called the local Hearth dealer, but was looking to build a hearth extension for some savings rather than buy a pre-fab from them.

 

[breathebeast]

Hey, cheaper than what I ended up paying by 50%!!

Which reminds me, I have most of that sheet left if anyone wants it for a hearth project in CT....

 

[84td]

I was in the same situation, tiny hearth. I am rebuilding it now. I just used plywood directly on the hardwood and put durarock over that and into the fireplace. I am going to mortar slate stones onto the whole thing. Got the plans right off woodstocks site for building a hearth pad.

Yours looks really good. I am going with stone because there is no chance of it cracking where the cement to wood joint is, the state rocks are almost 1/2in thick.