New Hearth/Surround Project

[chad101]

I spent the better part of last winter learning how to run my new stove; a big thanks goes out to everyone on this site!!

I built a horrible brick surround last fall. As you see from the attached picture, I created something I was terribly embarrassed of. I couldn’t wait for the opportunity to tear this thing down. Last weekend, I spent the better part of a day, chiseling away one brick at a time.

I do not want to make this mistake again. I have all summer and I plan on taking my time.

I’m looking for ideas. Any tricks, preferred materials, designs etc are all welcome. My initial plan was to use large river rock…until I seen the price. I just can’t come off $700 for 1.5 tons (dealer estimate).

This will be my thread for the entire duration of this project.

 

[chad101]

Looked around in the gallery and found a some interesting photos...

https://www.hearth.com/gallery/pics/woodcoal/source/jot3etc.html

https://www.hearth.com/gallery/pics/woodcoal/source/encore_more.html

https://www.hearth.com/gallery/pics/woodcoal/source/tx-buck-91-decor.html

Has anyone had to reinforce their floor joists? Some of these surrounds look extremely heavy!!

 

[Capt]

Heck, I like all 3 of those! But I'd have to say, if I had to choose, it would be #3. Good luck!

 

[chad101]

Yea, the 3rd pic looks good. I'm still poking around & pricing everything before I make up my mind.

I am slightly leaning towards a slate tile for the backer and flagstone for the hearth pad.

 

[fossil]

What stove is it? Looking at the pics, I'm assuming that whatever you're doing to the walls is purely cosmetic, and not intended to reduce clearances to combustible materials. Am I seeing this correctly? Rick

 

[chad101]

What stove is it? Looking at the pics, I'm assuming that whatever you're doing to the walls is purely cosmetic, and not intended to reduce clearances to combustible materials. Am I seeing this correctly? Rick

Stove: Hearth Stone Heritage (w/ double wall pipe).

Yes, the wall is a cosmetic fix. But, I plan on adding some heat protection. At least 2 or 3 layers of Durock (cement board). The hearth pad will be extended out 6ft from the corner and heavily insulated with cement board (6+ layers) and stone, brick, or tile over it.

 

[chad101]

It's been awhile since I've made an update. I'm making progress on the hearth pad. As soon as I get some batteries for my camera, I'll post a few pics.

I built the frame w/ 2 x 4s (wide side up – i.e. 3 1/2"); all inner supports "studs" are 8" on center to support the stove. And a sheet of 3/4" plywood was screwed in on top.

So far I have 3 layers of 1/2" Durock; each layer is (besides the first, which was screwed down) secured with a 1/4" layer of unmodified thinset. I'm waiting 24 hrs between layers so the thinset has time to cure.

 

[Intheswamp]

It's been awhile since I've made an update. I'm making progress on the hearth pad. As soon as I get some batteries for my camera, I'll post a few pics.

I built the frame w/ 2 x 4s (wide side up – i.e. 3 1/2"); all inner supports "studs" are 8" on center to support the stove. And a sheet of 3/4" plywood was screwed in on top.

So far I have 3 layers of 1/2" Durock; each layer is (besides the first, which was screwed down) secured with a 1/4" layer of unmodified thinset. I'm waiting 24 hrs between layers so the thinset has time to cure.

Currently, by my figures, you are at R=0.7. That sound about right?

Just trying to be sure my thinking is still on track.

I'm curious, what do you mean by "unmodified" thinset?

Keep up the good work!
Ed

 

[begreen]

Sounds pretty solid. There is enough support there for anything. For a good anchor, the top layer of durock should be screwed all the way through to the plywood. 3 lyrs of cement board (R .26 = R.78). Heritage is specced out for a hearth at R = 1.2, so this appears to be shy of spec. If the top layer of durock is not already cemented in place, can you add a 1/2" layer of micore or fiberfrax?

 

[Intheswamp]

You're right, BG. I was looking at another location on r-values and they listed r.20 for the durock...here on hearth.com and at the USG website it is listed at r.26. Add in maybe r.1 for 1/2" of mortar (two 1/4" layers) for maybe r=.88 ????? I guess in calculations like this it wouldn't be a bad idea to leave the small figures out of the equation and use them for a buffer?

Ed

 

[chad101]

First layer was screwed into the plywood. I plan on going 5 layers...maybe 6 for the hearth, with a layer of flagstone on top. Still need to get some batteries; should have some pics up by this weekend.

Considering the wall protection, 2 or 3 layers of durock is going to stick out 1" to 1 1/2" inches, how would I cover the edges? I don't think trim would be a good idea

 

[begreen]

5 layers is a lot of cement board, but it will be R = 1.3 when done and will weigh a ton.

Read up on wall protection first. Just one layer is sufficient, it's the 1" air gap behind the wall shield that does all the work.

 

[chad101]

5 layers is a lot of cement board, but it will be R = 1.3 when done and will weigh a ton.

Read up on wall protection first. Just one layer is sufficient, it's the 1" air gap behind the wall shield that does all the work.

How do I achieve this 1" air gap for wall protection (how is the cement anchored to the wall)?

I finished the 4th layer of Durock today; not sure how many layers I need for the side of the hearth though (so far I have 2 on the sides).

 

[chad101]

One more angle

Edit: The seams are staggered (criss-crossing the boards) between layers.

 

[chad101]

I'm curious, what do you mean by "unmodified" thinset?

Keep up the good work!
Ed

Sorry, I didn’t see this reply..

It's generic tile mortar without latex/polymer additives (I paid $9.50 for a 50 pound bag)

I can’t get too technical as why unmodified thinset is preferred (I know it’s cheaper lol). All I can say is every hearth construction tutorial I reviewed online calls for unmodified thinset; that’s why I used it.

 

[begreen]

5 layers is a lot of cement board, but it will be R = 1.3 when done and will weigh a ton.

Read up on wall protection first. Just one layer is sufficient, it's the 1" air gap behind the wall shield that does all the work.

How do I achieve this 1" air gap for wall protection (how is the cement anchored to the wall)?

I finished the 4th layer of Durock today; not sure how many layers I need for the side of the hearth though (so far I have 2 on the sides).

There is no wall shield required if the stove's full clearances are honored. If a wall shield is needed to reduce clearances, here is a link to USG's instructions for a Durock wall shield:

http://literature.usg.com/pdf/CB198.pdf

and here are some general instructions:

https://www.hearth.com/econtent/index.php/articles/stove_wall_clear

https://www.hearth.com/econtent/index.php/articles/wood_stove_clearances_installing_it_safely

https://www.hearth.com/econtent/index.php/articles/installing_a_woodstove

 

[fossil]

If you've got the manufacturer's required wall clearances, don't even mess with constructing a wall shield with an airspace. If you don't have the manufacturer's required wall clearances, then make sure the manufacturer allows a reduction with an appropriately constructed/installed shield. Putting up a vented wall shield is a PITA, so if you don't need it, don't bother. The specs are more than conservative enough on the safe side...just stick with them. As long as you meet the minimum required clearances from combustible materials from the stove to the original wall, you can decorate the wall with any sort of non-combustible materials you want, even though they will then encroach into that clearance space. Rick

 

[chad101]

You're right, I'm not sure why I thought I still needed wall protection. Based on the owner's manual (see attached photo - second post), I have more than enough room for a corner install (without wall protection). I finished my 5th layer today. BUT, I have enough Durock to do 1 more layer So, I'll do 6 layers and call it a day.

 

[chad101]

Clearances, (part 1 of 2).

 

[chad101]

Clearances (part 2 of 2).

 

[chad101]

A local contractor suggested I sister the joists running below the hearth to support the weight. I think I may have overlooked a critical step....

One problem...my floor joists are 14' long; my crawl space opening & location will not allow me to do this!!

Based on my fuzzy math, when the project is complete the combined stove + hearth weight is over 2000 lbs!

1, Hearth pad (as is), including lumber with 6 layers of Durock (12 sheets total) + motor (almost 2 - 50 pound bags) weighs around 560 lbs.
2, Hearthstone Heritage 475 lbs.
3, 1/2 ton of 2" thick flagstone @ 1000 lbs (44.6 sq ft)

Total: 2035 lbs

Since I can't sister the joists, I was thinking about buying some floor jacks & 4 x 4s. The 4 x 4s would run perpendicular to the joists directly below the hearth. With the floor jacks sitting on solid concrete blocks. Does this sound feasible?

 

[chad101]

I slacked off as far as updating this thread goes....

I finished the hearth, just wanted to post pic

 

[Intheswamp]

I slacked off as far as updating this thread goes....

I finished the hearth, just wanted to post pic

It looks mighty nice, Chad. What did you end up doing with the floor support?

 

[scoooter]

Great job, wanna come do one for me?

Scott

 

[chad101]

I slacked off as far as updating this thread goes....

I finished the hearth, just wanted to post pic

It looks mighty nice, Chad. What did you end up doing with the floor support?

Thank you

Right now I'm using floor jacks (on concrete footers) and 4x4s.

My long term goal (next year) is to sister the joists running below the hearth and maybe a steel 'I' beam (held up w/ jacks) which would cross the joists directly below the stove.