Replacing Prefab with Freestanding Stove - Basics

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
Hey guys. looking from some basics. I just bought a 1970 house that has an old prefab that I plan on removing and replacing with a free standing wood stove in Alcove. I have installed a couple inserts before in regular mason chimneys with insulated flex pipe and they were pretty straight forward but have never installed a free standing unit before. I am looking to demo this prefab:

UNADJUSTEDNONRAW_thumb_8b73.jpg

And replace it with something like this:

Wood Stove Alcove.jpg

So. Since I have never installed a freestanding stove, I am looking for some answers to some basic questions. Above the current room in the pic above is an attic with decent space to stand and work. The current situation on the roof appears to be a chase with chimney chase cover. Here is a pic:

5AF0E1FB-D33C-4D11-B1C5-2B667F1E829F.jpeg

Ok. Now. Forget the demo and work involved with that. Forget the clearances for now. I am just looking to get answers on install and pipe options to get a better understanding of Class A pipe components.

Do all I need is the following items in this pic?

flat-ceiling-class-a-chimney_1 (1).jpg

- Double Wall Black Stove Pipe
- Ceiling support and trim collar
- Attic Sheild
- Class A Chimney Pipe
- Chimney Chase cover
- Chimney Cap

Is that all I need for pipe from stove to sky? Does the chimney cap connect right to the Class A Chimney Pipe? How do you seal the chase cover and cap from weather?

Thanks for your help.
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,334
South Puget Sound, WA
Whatever the choice, don't replace it with that old Franklin style fireplace. Might as well leave things as they are.
 

kennyp2339

Minister of Fire
Feb 16, 2014
5,155
07462
From the ground up - hearth depending on stove, will depend on whether it needs ember protection or something with more r-value if building on a combustible floor, if is a cement pad then its non combustible to begin with.
Nice design in the second picture, but you will need to follow your particular stoves instructions for alcove design if using combustible materials, if your using non combustible materials such as metal studs, hardie board, rock wool ect.. then the stove will still need to meet the measurement from combustibles within - meaning if a stove has 24" from a combustible wall then you need to not have any combustible materials within that 24" envelope, sheet rock and unseen wood studs.
The stove may need an adapter collar for the double wall pipe for connection, then double wall to ceiling support box, I know I had to get an adapter piece to mate the ceiling support box to the dvl I was using, from the ceiling support box class A chimney pipe, attic insulation shield to cover the open ceiling support box, class A pipe through the roof, roof flashing & storm collar, more class A pipe to meet the 3,2,10 rule (2ft above peak of roof when at or near the peak, or 3ft above everything else within 10ft (counteracts slope of roof) you may or may not need a brace (more then 2 sections or more should braced) and depending on your roof slope you may need a roof cricket to deflect sliding snow or ice.
Th for the water blockage it is recommended to seal with silicone caulk the storm collar area and the seam on the lengths of class A pipe that are outdoor. The roof flashing has a lip that goes under the top side of the shingles and then over the top of the bottom side of shingles, it also gets a bead of asphalt tar under the lip before nailing, all nail head should get a bead of tar to.
Its best to buy everything as one system - so stick to one brand so all parts mate together, also the instructions for through the roof designs are pretty easy to follow.
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
From the ground up - hearth depending on stove, will depend on whether it needs ember protection or something with more r-value if building on a combustible floor, if is a cement pad then its non combustible to begin with.
Nice design in the second picture, but you will need to follow your particular stoves instructions for alcove design if using combustible materials, if your using non combustible materials such as metal studs, hardie board, rock wool ect.. then the stove will still need to meet the measurement from combustibles within - meaning if a stove has 24" from a combustible wall then you need to not have any combustible materials within that 24" envelope, sheet rock and unseen wood studs.
The stove may need an adapter collar for the double wall pipe for connection, then double wall to ceiling support box, I know I had to get an adapter piece to mate the ceiling support box to the dvl I was using, from the ceiling support box class A chimney pipe, attic insulation shield to cover the open ceiling support box, class A pipe through the roof, roof flashing & storm collar, more class A pipe to meet the 3,2,10 rule (2ft above peak of roof when at or near the peak, or 3ft above everything else within 10ft (counteracts slope of roof) you may or may not need a brace (more then 2 sections or more should braced) and depending on your roof slope you may need a roof cricket to deflect sliding snow or ice.
Th for the water blockage it is recommended to seal with silicone caulk the storm collar area and the seam on the lengths of class A pipe that are outdoor. The roof flashing has a lip that goes under the top side of the shingles and then over the top of the bottom side of shingles, it also gets a bead of asphalt tar under the lip before nailing, all nail head should get a bead of tar to.
Its best to buy everything as one system - so stick to one brand so all parts mate together, also the instructions for through the roof designs are pretty easy to follow.
Awesome. Thank you. I wont need to do the roof flashing and shingles as I have a chimney chase already there. I think I just need Class A out of house (still inside chimney chase) to Chimney chase cover. Storm collar and cap. Correct?
 

kennyp2339

Minister of Fire
Feb 16, 2014
5,155
07462
I think I just need Class A out of house (still inside chimney chase) to Chimney chase cover. Storm collar and cap. Correct?
Negative, you more then likely going to need some custom tin knocking to make a cover that's tight to the class A, has 4 creases to become rigid and cover the chimney chase, the class A should stick out a foot above that chase cover with its own chimney cap and silicone sealed between the chase cover and class a pipe, storm collar should be necessary and prob would make it look like some ufo is trying to land on your chimney chase.
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,334
South Puget Sound, WA
Still havent decided what to go with. This pic was posted to just show the design. Probably going to go with a Jotul F500.
Whew, that's better. You will need to be mindful of mantel clearances, but that's a good stove. As an alternative, a non-combustible mantel could be installed.
 

Poindexter

Minister of Fire
Jun 28, 2014
2,256
Fairbanks, Alaska
Looks like you are on the right track, double wall telescope to ceiling, an expensive box, class A through the attic, another expensive box, then class A with a storm shield as already discussed worked into the shingles, meet 3-2-10, you should be golden.

Our local homeowner's insurance agent is an old friend, he pretty much told us that if we installed the chimney ourselves our homeowner's premium would go up a lot but if we paid for a pro chimney install it wouldn't go up at all. We went with the pro install. We are paying about a dollar per week additional homeowner's for the wood stove; but if we have a loss related to the chimney our insurance company will write us a a check and go after the installer.

As has already been pointed out you will need to check your clearance to combustibles carefully and choose a stove that fits your alcove. Mantel height above stove is one of the measurements on the checklist, so is width (or depth) of hearth coming out from in front of the stove door.

I am not in your living room with a tape measure. It -might- make sense to lose two layers of brick off you existing hearth, turn the bottom layer on its side to present a smooth top, extend it out into floor a bit and possibly leave the mantel alone. I can assure you if you do have a fire related loss the adjuster will be checking all your clearances before they write a check.

Your existing chimney above the roof looks, in the picture, like real brick, not sheet metal that with an awesome paint job on it. If the existing fireplace works reasonably well- I don't see a lot of smoke staining on the brick - it might make sense to leave the fireplace alone and put a new install freestanding woodstove somewhere else in the house.

Just my two cents over the internet.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
Negative, you more then likely going to need some custom tin knocking to make a cover that's tight to the class A, has 4 creases to become rigid and cover the chimney chase, the class A should stick out a foot above that chase cover with its own chimney cap and silicone sealed between the chase cover and class a pipe, storm collar should be necessary and prob would make it look like some ufo is trying to land on your chimney chase.
Yes a storm collar is needed. Just being siliconed to the chase cover will never hold up.
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
As promised here are some additional pics.
3DF2C774-B88C-4252-BA2D-907863E88701.jpeg

Current set up. Everything behind the brick is a chase. Not sure why the prefab is offset. Flute goes straight up through ceiling. Into crawl space/attic and out the roof via a chase with brick facade.

05628987-988C-4146-95FE-3796901CF161.jpeg

Current make and model.

39F0858E-FB94-4505-820B-90094B4C10E8.jpeg

Crawlspace attic shot.

67291BF4-DC40-4C5C-B934-E487D29506D7.jpeg

Looking down chase

D96C8E5F-C09B-4764-B135-94AC182D65AD.jpeg

Out the roof chimney

Any thoughts if what I intend to do is doable? Appears to be pretty straight forward and besides the demo, potentially easier than putting in an insert.

Thoughts?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
As promised here are some additional pics.
View attachment 260682

Current set up. Everything behind the brick is a chase. Not sure why the prefab is offset. Flute goes straight up through ceiling. Into crawl space/attic and out the roof via a chase with brick facade.

View attachment 260683

Current make and model.

View attachment 260684

Crawlspace attic shot.

View attachment 260685

Looking down chase

View attachment 260686

Out the roof chimney

Any thoughts if what I intend to do is doable? Appears to be pretty straight forward and besides the demo, potentially easier than putting in an insert.

Thoughts?
An insert most likely is not an option. If you do remove the fireplace make sure you leave support for the masonry structure on the roof. The load currently is being transferred down through those 2x4s
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
An insert most likely is not an option. If you do remove the fireplace make sure you leave support for the masonry structure on the roof. The load currently is being transferred down through those 2x4s
Yeah. Definitely not looking at an insert. Looking to install a freestanding wood stove.
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
Yeah. Definitely not looking at an insert. Looking to install a freestanding wood stove.
I am sure it is possible. Just pay attention to the load of that masonry sitting on wood structure
 
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Poindexter

Minister of Fire
Jun 28, 2014
2,256
Fairbanks, Alaska
Or take it off. My inclination would be to remove the ambiance burner, remove all the brick, including the brickwork above the shingles. Your ceiling joists and rafter will line up perfectly for a strait up and out Class A chimney, and with a bit of luck you will have the chimney far enough off the back wall to install just about any freestanding stove on the market and meet rear clearance without any elbows.

If you go that route have the chimney installer do what has to be done now, but leave you the correct storm shield to have installed whenever the shingles are replaced next. Just put on a high shelf in the garage.

It is quite a bit of demolition, and I still think your existing brick hearth won't come far enough out in the room to meet code, but I would honestly pull all that brickwork too, cut away a bit of the flooring and then put down maybe ceramic tile with some hardi board under if needed to make it flush with the existing flooring.

Or leave it alone. I see a little smoke staining above the existing firebox, but not much. No idea how much it was used. It may be a miserable smoky mess used only once by each of the previous owners of the house, or it may work pretty good. If it works good I would be inclined to see if I could put a freestander somewhere else to save money on ibuprofen from doing all that demolition.

The once thing I personally would not do is some half way hack in between all or nothing.
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
Thank you. This is exactly what I plan on doing. The wood floor in that room is coming out regardless. It’s in bad shape.

I was planning on knocking out all the brick down to the studs. Marking out the hearth for clearances. Installing new wood floor. For the hearth I was planning on 1/2” hardibord over 3/4 subfloor and then tile on top. Should be roughly 1 1/2 high to match new 3/4 inch wood floor over 3/4 in subfloor. Is that good enough for the hearth? Tile over Half inch hardy??

Also, Why would I have to do anything above the roof line? The chase/chimney is there, it’s wrapped in brick and looks good. Why can’t I just run the class A out the top and cap it with another chimney chase cover like this?

31CE7192-6288-4997-955C-EF51CF0CB23E.jpeg
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
Thank you. This is exactly what I plan on doing. The wood floor in that room is coming out regardless. It’s in bad shape.

I was planning on knocking out all the brick down to the studs. Marking out the hearth for clearances. Installing new wood floor. For the hearth I was planning on 1/2” hardibord over 3/4 subfloor and then tile on top. Should be roughly 1 1/2 high to match new 3/4 inch wood floor over 3/4 in subfloor. Is that good enough for the hearth? Tile over Half inch hardy??

Also, Why would I have to do anything above the roof line? The chase/chimney is there, it’s wrapped in brick and looks good. Why can’t I just run the class A out the top and cap it with another chimney chase cover like this?

View attachment 260691
You can just run class a through what's there as long as that masonry is properly supported.
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
Perfect.

Regarding the hearth.

Option 1: 3/4 subfloor. 1/2 hardibord. Tile

Option 2. Remove subfloor. 1/2 micore. 1/2 hardibord. Tile.

option one would sit 1/4 inch proud of wood floor. Option two would be flush.

Thoughts?

thanks for all your help
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
Perfect.

Regarding the hearth.

Option 1: 3/4 subfloor. 1/2 hardibord. Tile

Option 2. Remove subfloor. 1/2 micore. 1/2 hardibord. Tile.

option one would sit 1/4 inch proud of wood floor. Option two would be flush.

Thoughts?

thanks for all your help
Decide on a stove that will determine what is required for the hearth
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
Ok. I think I have everything figured out. Looking for another set of eyes to confirm.

Stove:
I have narrowed it down to the following:
1. Woodstock Keystone
2. Hearthstone Heritage
3. Hearthstone Manchester
4. Hearthstone Green Mountain 60
I will decide on which model after demolition and viewing products in person.

Install.

Hearth Construction. Depends on stove. Aiming for as flush as possible.

Stove Parts (Bottom Up):
  1. Stove
  2. Stove Top Adaptor
  3. Telescoping Stove pipe - Duravent DVL
  4. Duravent 45* elbows (x2)
  5. Duravent DVL Stove pipe
  6. Chimney Adaptor
  7. Ceiling support box ( will be inside chase approximately where current mantel is. It is looks finished when looking up chase)
  8. Insulation Shield for first entry in chase
  9. Class A Pipe - Durvent Duratech
  10. Firestop Radiation Shield for entry into attic.
  11. Insulation shield for entry into attic
  12. Chase cover
  13. Storm collar
  14. Cap
Again. Looking to go from this:

IMG_0324.JPG

To this:

Berkshire Fireplace.jpg

Hopefully getting to something like this:

Alcove29.jpg

or this:

alcove5.jpg

How am I looking on parts? I think I covered everything?

Thanks!
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
22,190
central pa
Ok. I think I have everything figured out. Looking for another set of eyes to confirm.

Stove:
I have narrowed it down to the following:
1. Woodstock Keystone
2. Hearthstone Heritage
3. Hearthstone Manchester
4. Hearthstone Green Mountain 60
I will decide on which model after demolition and viewing products in person.

Install.

Hearth Construction. Depends on stove. Aiming for as flush as possible.

Stove Parts (Bottom Up):
  1. Stove
  2. Stove Top Adaptor
  3. Telescoping Stove pipe - Duravent DVL
  4. Duravent 45* elbows (x2)
  5. Duravent DVL Stove pipe
  6. Chimney Adaptor
  7. Ceiling support box ( will be inside chase approximately where current mantel is. It is looks finished when looking up chase)
  8. Insulation Shield for first entry in chase
  9. Class A Pipe - Durvent Duratech
  10. Firestop Radiation Shield for entry into attic.
  11. Insulation shield for entry into attic
  12. Chase cover
  13. Storm collar
  14. Cap
Again. Looking to go from this:

View attachment 260743

To this:

View attachment 260744

Hopefully getting to something like this:

View attachment 260745

or this:

View attachment 260751

How am I looking on parts? I think I covered everything?

Thanks!
Check the alcove clearances of those stoves. Some can be quite large. Also most require a height of around 7'
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
Check the alcove clearances of those stoves. Some can be quite large. Also most require a height of around 7'
Noooooooooo! Crap

1. Woodstock Keystone - Specs show not approved for alcove installation. Out!!!!!!!! CRAP. This was my favorite stove.
2. Hearthstone Heritage - Specs show 34" from stove top to alcove ceiling which is 5 1/2' from hearth. Good. Specs say "Does not require insulated hearth pad". - WHAT DOES THAT MEAN?
3. Hearthstone Manchester - Specs show 62" from floor. Call it 5 1/2 from hearth. Good. Specs say "Does not require insulated hearth pad". - WHAT DOES THAT MEAN?
4. Hearthstone Green Mountain 60 - Specs show 62" from floor. Call it 5 1/2 from hearth. Good. Specs say "Does not require insulated hearth pad". - WHAT DOES THAT MEAN?
5. Adding Jotul F500 - Specs show 41" off top of stove. Call it 6'. Doable but also requires heat shields all around unit and beefed up hearth to r value of 1.6. Not going to be flush.

In summary.

Option 1: Probably looking at only Hearthstone stoves once I get clarification regarding the hearth. Was hoping to go flush with hearth which would be 3/4 subfloor. 1/2 hardiboard and roughly 1/2 for tile. This would put hearth a 1/4 to 1/2 inch above wood floor.

Option 2: Forget the alcove. Demo everything to ceiling and do a standard freestanding install. (would have to see load bearing issues regarding chimney and chase. Not sure if this is even an option.

Wood stove are complicated. Uff!
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,334
South Puget Sound, WA
What is shown in the examples is not as much an alcove as a simulated fireplace install. That seriously complicates the installation and stove choices. But if that is the plan, consider constructing the sides entirely out of non-combustible materials (including the studs), a non-combustible mantel too. That will make stove choice easier. Clearances are to The Keystone is probably out due to clearances and side loading. Look at the Blaze King Ashford instead.

A much simpler and less costly install would be to do a flush rear wall install with no alcove wings and no mantel. As noted earlier, check the stove specs for alcove installation including hearth requirement and clearances including ceiling height.
 

jjmac1235

New Member
Nov 28, 2018
51
Upstate NY
What you are showing in the examples is not as much an alcove as a simulated fireplace install. That seriously complicates the installation and stove choices. But if that is the plan, consider constructing the sides entirely out of non-combustible materials (including the studs), a non-combustible mantel too. That will make stove choice easier. Clearances are to The Keystone is probably out due to clearances and side loading. Look at the Blaze King Ashford instead.

A much simpler and less costly install would be to do a flush rear wall install with no alcove wings and no mantel. As noted earlier, check the stove specs for alcove installation including hearth requirement and clearances including ceiling height.
Yeah. Probably going to have to go back to the drawing board and do a rear wall install. I wont know if I can even do that until I demo the whole thing. I assume the current chase is not load bearing but now need to re-access. I can probably just sure up the framing in the attic to carry load of chimney over the ceiling rafters. The wall behind the chase is staying and I think its carrying most of the load there. The rafters in the ceiling are left to right and carrying the whole roof, but they did cut one of them to put in the zero clearance. Back to the beginning. Need to figure it out.

Thanks for the help
 

begreen

Mooderator
Staff member
Nov 18, 2005
84,334
South Puget Sound, WA
It can be made entirely non-combustible with a metal stud, cement board clad and brick veneered enclosure if this is what the vision and budget want.
 

Dakotas Dad

Minister of Fire
Mar 19, 2009
1,502
Central Kentucky
Click that link in my signature line.. It doesn't contain a lot of discussion or description since the great photobucket debacle.. But might give you some ideas on how to get to where you want to be..
 

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