Install of Freestanding Stove in Brick Alcove

[mrroboto]

Hello everyone,

I posted a while ago at the figuring out stage of removing an old Napoleon NZ2000 zero clearance fireplace that was set into a brick alcove / hearth. We recently moved into this home, and discovered that unit was no longer serviceable. It has now been removed (the guy unfortunately went higher than necessary removing bricks so there's now more to repair. The chimney was lined with 8" clay rounds, many were cracked and they've already been removed. The brick chimney is in the house, not outside.

The cavity was exposed and a professional was brought in for recommendation. Here's the hole -



I was given the option of -

• another zero clearance installed (big money and requires significant labour beyond my skills)
• a mason constructed firebox in the hole then slide an insert in (about 2/3 - 3/4 the cost of the zero clearance and also requires significant labour beyond my skills)
• cosmetically pretty up the hole and slap a freestanding wood stove in that hole (I can do a lot of the labour)

I'm leaning towards option 3 because -

• by far the cheapest both labour, install complication and materials wise.
• the area is already safe and suitable for a freestanding stove (except I need to extend the hearth forwards a few inches for adequate clearance in front of the door to combustibles) All that needs to be done is make it look good.
• I expect I'll get the most efficient use of my wood / best heat into my home.
• I don't like the idea of the wood burning appliance being buried behind masonry, if a fan fails, something needs adjustment etc I can see it and do it easily.
• Stove could easily be replaced at end of life, rather than go through all this again.

I can get a Drolet ht2000 with blower at a discount locally. It will fit in the space and should give me the heat output and burn times I'm looking for. The home is 2000 sqft with vaulted ceilings. I'm hoping all the masonry will act as a big heat battery. Now my plan -

• Clean out the remains of the heat exchange ducts and fiberglass you can see at the top of the cavity.
• Install some kind of plate on the ceiling of the cavity to seal and insulate that area.
• Remove the remaining bricks on the front wall, so I'm left with just the end face of the bricks on the angled wall.
• Cut away the 4-5 bricks standing proud on the floor where the front wall used to be.
• Level the entire floor and install a single piece 1" thick slate from an old pool table (already in hand).
• Cut away the protruding concrete blocks on the right section of the back wall (mason consulted and said this would not impact the structure of the chimney) to create a flush surface and also install a matching piece of slate against the entire back wall.
• For the inner side walls, I haven't yet decided whether to go with two more pieces of slate, or to run a bricks up those wall. If brick, I'll give self install a shot, but may bring in the mason to do those inside walls if I find it beyond my ability.
• Have a pro install a stainless chimney liner and hook up the stove.
• My goal here is a a strong heater that will keep the house toasty when it's too cold for the heat pump, which is about 3 to 4 months of the year.

Questions -

• Will the one piece slate be more susceptible to cracking? Should I cut it up into two or four tiles?
• To create a flat surface to install the slate on, I was planning on a layer of self leveling product, pros or cons or recommendations?
• Should I lay the floor slate dry on that level surface or use a mortar?
• What is the best adhesive to attach the slate to the back wall?
• Can anyone point me to a good write up on insulating/sealing the top of the alcove?
• The stove tech is advising that insulating my chimney liner is a wasted expense. From my reading here the consensus is the opposite. Thoughts? Canada, lowest temps -25C.
• Is the outside air intake worth keeping? Can I even hook it up to the HT2000?

More questions and pictures to come,

Rob

 

[EbS-P]

So will need is a wett inspection? Question would apply to the insulated liner. Does the chimney masonry have proper clearance to combustibles? Jury plan on insulation it’s not that much more $$$ and won’t come back that it needs to be done after inspection.

I would use the self leveler and then put thin set on top to set the slate on.

Sealing the top. I would use masonry screws to secure angle metal to the brick. And then cut a piece of sheet metal to fit. With a a hole for the liner. Stiffen as needed after install. Or make it in two pieces. Insulate with mineral wool insulation.

Keep the oak and use of possible.

 

[mrroboto]

Thanks EbS-P,

Yes, WETT inspection is required and will be provided by the shop installing the liner & final stove hookup. I assume the chimney masonry clearances are good they had a look at the chimney and said there was no problem with it, but I'm leaning towards your opinion of just do the insulation anyway.

Regarding sealing the top, would you try to air seal around the perimeter of that sheet metal, if so with what product?

​

 

[EbS-P]

Thanks EbS-P,

Yes, WETT inspection is required and will be provided by the shop installing the liner & final stove hookup. I assume the chimney masonry clearances are good they had a look at the chimney and said there was no problem with it, but I'm leaning towards your opinion of just do the insulation anyway.

Regarding sealing the top, would you try to air seal around the perimeter of that sheet metal, if so with what product?

​

High temp silicone if I could do it cleanly. I always make a giant mess of it. I didn’t seal mine with it. But stuffed gaps with rock wool.

It just makes me pause any time contractor says insulation isn’t a good idea. For the reasons that it corrects other’s mistakes for clearances (roofers often just replace sheeting and have it touch the masonry) and reduced creosote by keeping flue gas temps higher.

 

[mrroboto]

Had time to get some work on the hearth this weekend.

• excess bricks removed from sides
• back wall cut flush
• extra electrical removed
• self leveling concrete base poured (it's hard to tell from the pics but the self leveling layer is about 3/4" at the front edge)

Next is cutting and laying slate.

 

[mrroboto]

Got busy and hadn't had to to post the rest of the pics - side and back walls plumbed and slate installed floor and back. Single piece on the floor, two tall pieces on the back wall with the seam running behind where the flue will be. Large format tile thinset used for the slate. Liner (16' of tubinox single wall) is test fitted and sitting in place held by clamp.



Starting on the brickwork coming up the side, go easy on me, first time laying brick!



Pretty happy with how it's coming together so far.



Arch form shimmed in place with bricks layed on top.



Form removed after the mortar set, missing bricks filled in. I found this was by far the most challenging part, getting those bricks in relatively square and even was difficult. Happily, pointing the mortar made a big difference in how uniform it looked, and once the motar was dry it closely matched the old stuff and further hid my imperfections.

At this time, my piece flue liner (still not installed) is sitting on the piece of telescoping double wall that will allow the stove to be slid in.

 

[mrroboto]

Since the last picture, I had my WETT guy come out, install the flashing at the top of the chimney, install the flue liner (it's top supported, hanging from the flashing). I was then able to remove the wood stand that was holding up the flue liner, and bring in the stove. HT2000, slid into the house on rollers of 2" pipe on top of plywood. Then made a 2x4 cradle that supported the stove and stuck out to either side and jacked it up with two car jacks till it was a few inches higher then the floor of the hearth. Then slid two 2x4s under the stove and butted them against the back wall of the hearth to act as rails and supported their front ends so there was a slight slope backward making it easy to slide the stove backwards into place.

Final install and WETT inspection completed. The stove has been running more or less continously now since Christmas and has cut our electric heat usage almost to nothing.

There's still some odds and ends I need to do to consider the project finished. A bit more mortar work and pointing that'll have to wait until the fireplace is shut down in the spring. I think I will also file down the edge of the slate floor to a bullnose profile. I think I'll use a piece of hardwood or steel with the profile I want with sandpaper attached, and run it along the edge as required. The slate is soft like soapstove and can be sanded, filed or even carved if I had the skill.

The two grills on either outside wall of the brick are also still open to the cavity above the stove, I think I will install some fans in each of those on a temp controller to help move air out into the room. At the same time I will install rockwool on the center portion of the alcove ceiling to insulate the alcove from the chimney.

 

[EbS-P]

Looks very nice. I like the air blaze fans. They have a temp controller and are really really quiet. I have one on the fireplace floor pointed up the back of the stove. The controller is not perfect, as once it’s set for high temperature operation you can only change the temp setting not the fan setting without like 9 key presses. It doesn’t take much air flow.

 

[begreen]

Very nice work, you've done quite well for a first-time masonry project.

 

[TomMcDonald]

Fantastic result. Job well done.

 

[FPX Dude]

Very nice, luv da' arch!

 

[Newbie78]

Brilliant!