Block Off Plate - Freestanding Stove Interior Chimney Install

[POW16]

Hello all,

I am new to the wood stove world (as an owner at least). I recently bought a nearly new VC Intrepid II and a Metal-Fab Super Flex Stainless Steel 316L 6"x 25' chimney liner kit with a Tee. I am installing the liner into our existing interior masonry chimney, which is pretty much in the center of the house. The house isn't that large, 1,500 SF. It's a summer beach home that I'd like to extend the season (great fall/early winter fishing). I've done a lot of research on this amazing site but am unsure of a few things:

1. Should I install a sheet metal block off plate? I will be installing the liner with a vent cap and top plate. I plan on stuffing some insulation into the top couple of feet of the existing chimney around the new liner.
2. I plan to install the stove on the hearth pad with maybe 1/3rd of the stove in the firebox. I've done all of the measurements and the existing hearth/mantle meets all clearance requirements.
3. Will I lose too much heat up the existing chimney or will that heat going up the chimney actually heat the brick and provide heat to the second floor?
4. I've attached photos of the house, the Intrepid II and the fireplace.

I really appreciate any insight that you all have on this.

 

[begreen]

Welcome. Do you have the legs for the stove? The measurements and hearth requirements are based on the stove having its original legs attached. There was a short leg kit option for this stove which would be acceptable, following the hearth requirements for the short leg option. Regardless of option the stove should also have the bottom heat shield attached.

I would add a block-off plate. It will increased the amount of heat that stays in the house noticeably.

 

[POW16]

Welcome. Do you have the legs for the stove? The measurements and hearth requirements are based on the stove having its original legs attached. There was a short leg kit option for this stove which would be acceptable, following the hearth requirements for the short leg option. Regardless of option the stove should also have the bottom heat shield attached.

I would add a block-off plate. It will increased the amount of heat that stays in the house noticeably.

begreen,

Thank you for the input. I do have the legs, they are the standard legs you can kind of see them in the third picture.

 

[begreen]

The Intrepid is not a big stove, but it should make a nice chill chaser for fall/spring days. Expect a ~4-6hr burn time if the wood is well seasoned and the stove is in good working order.

 

[bholler]

Yes do a block off plate and insulate the whole liner not just the top

 

[POW16]

The Intrepid is not a big stove, but it should make a nice chill chaser for fall/spring days. Expect a ~4-6hr burn time if the wood is well seasoned and the stove is in good working order.

Yeah, ideally, I'd like to have an overnight burn but it's 99.5% a summer house and I will really only be out there during the fall and spring. Therefore, it doesn't make much sense having a huge stove. Also, the women in my family think it's "sooo cute".

 

[POW16]

Yes do a block off plate and insulate the whole liner not just the top

Bholler,

Do I really need to insulate the entire liner if it's an interior chimney and will be used only in Oct-Nov and March-April? I'd rather not spent the extra money unless it's necessary. As I am new to this, I'll defer to the experts.

 

[bholler]

Do you have 2" from the outside of the masonry structure to any combustible materials the entire length of the chimney? If not you need to insulate the whole thing yes. And besides it will make it work much better

 

[bholler]

Oct-Nov and March-April?

You can still have a fire start from heat transfer in that time

 

[kennyp2339]

1st off, nice home and nice stove, 2nd follow what Begreen is saying as far as clearances, hearth extension and perhaps the short leg kit. In an ideal world you will want to insulate the whole liner, it keeps the liner warmer and will reduce the chances of flu gases condensing and creating the dreaded 2nd stage creosote. I don't think its a big deal though if the liner isn't insulated, it doesn't sound like from your discription that you will be using the stove 24/7 for the whole winter season, plus the chimney is centrally located so it stands a better chance of staying warmer then a chimney located on an outside wall. As far as the block off plate I will recommend before putting the plate in you insulated the cavity above the plate, use roxal insulation, buy the big bag and try to get as much in there as possible then put the plate up, you will have a lean mean heating machine afterwards providing you use good dry wood <20% moisture content

 

[bholler]

I don't think its a big deal though if the liner isn't insulated

It is required by code if you dont have the proper clearance between the masonry and combustibles. And that code is there because it is possible for enough heat to be transferred through that masonry in the case of a chimney fire to the adjacent wood to cause combustion. There has been allot of testing and research done on this and that is how they came up with the requirements.

 

[kennyp2339]

It is required by code if you dont have the proper clearance between the masonry and combustibles. And that code is there because it is possible for enough heat to be transferred through that masonry in the case of a chimney fire to the adjacent wood to cause combustion. There has been allot of testing and research done on this and that is how they came up with the requirements.

I just edited my post, don't know what happened though, I tried to explain that the OP should look up there chimney, if they see regular brick and mortar they will def need a insulated liner, if it's a clay lined chimney a regular liner will work, if they have doubts please call a certified chimney sweep. It's not worth the risk, burning wood should be an enjoyable and safe experiance

 

[bholler]

if it's a clay lined chimney a regular liner will work

Nope insulation is still required by code with out that 2" between the masonry and combustibles doesn't matter if it is clay lined or not

 

[bholler]

here is the code out of irc the only way to over come these requirements is with a properly insulated liner

R1001.15 Chimney clearances. Any portion of a masonry chimney located in the interior of the building or within the exterior wall of the building shall have a minimumair space clearance to combustibles of 2 inches (51 mm). Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air space clearance of 1 inch (25.4 mm). The air space shall not be filled, except to provide fire blocking in accordance with Section R1001.16.

Exceptions:

1. Masonry chimneys equipped with a chimney lining system listed and labeled for use in chimneys in contact with combustibles in accordance with UL 1777 and installed in accordance with the manufacturers installation instructions are permitted to have combustible material in contact with their exterior surfaces.

2. When masonry chimneys are constructed as part of masonry or concrete walls, combustible materials shall not be in contact with the masonry or concrete wall less than 12 inches (306 mm) from the inside surface of the nearest flue lining.

3. Exposed combustible trim and the edges of sheathing materials, such as wood siding and flooring, shall be permitted to abut the masonry chimney side walls, in accordance with Figure R1001.15 provided such combustible trim or sheathing is a minimum of 12 inches (306 mm)from the inside surface of the nearest flue lining. Combustible material and trim shall not overlap the corners of the chimney by more than 1 inch (25.4 mm).

 

[kennyp2339]

Bhollar - just read the same thing as you posted. I guess the next question to the poster is to ask when the house was built and was it inspected by the building dept during construction, or are you going to get a permit for the stove installation?

 

[POW16]

Bhollar - just read the same thing as you posted. I guess the next question to the poster is to ask when the house was built and was it inspected by the building dept during construction, or are you going to get a permit for the stove installation?

here is the code out of irc the only way to over come these requirements is with a properly insulated liner
R1001.15 Chimney clearances. Any portion of a masonry chimney located in the interior of the building or within the exterior wall of the building shall have a minimumair space clearance to combustibles of 2 inches (51 mm). Chimneys located entirely outside the exterior walls of the building, including chimneys that pass through the soffit or cornice, shall have a minimum air space clearance of 1 inch (25.4 mm). The ).

kennyp2339 and bholler,

Thank you for the input. The house is very old - probably over 100 years. We have had the chimney maintained over the years by professional chimney sweeps. Our community is comprised of nearly 100% wood houses and I want to be extremely careful with this instillation.

Thank being said, I will ABSOLUTELY insulate the liner. Do you have any good recommendations on liner insulation? I'm thinking that a wrap may make sense.

 

[bholler]

Thank being said, I will ABSOLUTELY insulate the liner. Do you have any good recommendations on liner insulation? I'm thinking that a wrap may make sense.

Yes for you insulation wrap would probably be best.

I guess the next question to the poster is to ask when the house was built and was it inspected by the building dept during construction, or are you going to get a permit for the stove installation?

It shouldn't matter weather it is getting inspected or not. You should make it code compliant for safety reasons not because you are worried about it failing inspection.

 

[POW16]

Hello all. I am researching block off plates and wondering if I can use this type of sheet metal. Just concerned about the zinc-plated aspect of the sheet metal.

• Steel construction
• Zinc-plated
• 26-gauge

As always, thank you for all of the help.

 

[begreen]

That will work ok. The block off plate should not get hot enough for the zinc to outgas.

 

[POW16]

That will work ok. The block off plate should not get hot enough for the zinc to outgas.

Thanks begreen.

Do you think there's a better option out there? I'd like to do this job the right way.

 

[begreen]

That's the material I'd probably use if we had a fireplace.

 

[POW16]

That's the material I'd probably use if we had a fireplace.

Perfect, thank you. I'll be sure to document and take photos of the install.