Block off Plate- Yes or No

[Sain6815]

hey guys,

About to install the englander 30nc in the basement fireplace with full flex liner uninsulated. It's a solid interior masonry chimney and my goal is to heat the main level and the basement.

My question is, should I add a block off plate with insulation at the damper? I'm planning on insulating the top plate at the chimney cap. I don't want to lose the radiant heat that the chimney could provide to the upper level. Thoughts?

 

[bholler]

hey guys,

About to install the englander 30nc in the basement fireplace with full flex liner uninsulated. It's a solid interior masonry chimney and my goal is to heat the main level and the basement.

My question is, should I add a block off plate with insulation at the damper? I'm planning on insulating the top plate at the chimney cap. I don't want to lose the radiant heat that the chimney could provide to the upper level. Thoughts?

Yes block off plate and insulate the liner also. You heat with the stove not the chimney. And being an internal chimney you need 2" of clearance to combustible from the outside of the masonry structure of the chimney and any combustible materials. If you don't have that you need insulation on the liner to meet code and for safety.

 

[Sain6815]

And being an internal chimney you need 2" of clearance to combustible from the outside of the masonry structure of the chimney and any combustible materials. If you don't have that you need insulation on the liner to meet code and for safety.

We are good on clearances.

 

[bholler]

We are good on clearances.

Really? You have 2" of space all the way around the chimney from the top of the smoke chamber all the way up through the roof? Actually having that is extremely rare. If you do great but I would still insulate the liner to meet the ul listing and for performance. But it is not required for safety.

 

[Easy Livin’ 3000]

Really? You have 2" of space all the way around the chimney from the top of the smoke chamber all the way up through the roof? Actually having that is extremely rare. If you do great but I would still insulate the liner to meet the ul listing and for performance. But it is not required for safety.

Bholler, have you ever seen this? If so, was the chimney totally "floating", or if not, how was it tied into the framing of the house? I can't even picture this.

 

[bholler]

Bholler, have you ever seen this? If so, was the chimney totally "floating", or if not, how was it tied into the framing of the house? I can't even picture this.

You are allowed to run trim up against it. And it should be tied fast with anchor straps but yes pretty much it needs to be freestanding completely separate from the structure. Proper clearances on external chimneys are very rare I would say maybe 5%. But internal chimneys i have only ever seen one.

 

[Sain6815]

Haha. You are correct. I had a misunderstanding of clearance to combustibles. I just reviewed the codes as well and have an insulation blanket on the way.

 

[bholler]

Haha. You are correct. I had a misunderstanding of clearance to combustibles. I just reviewed the codes as well and have an insulation blanket on the way.

Good

 

[Easy Livin’ 3000]

You are allowed to run trim up against it. And it should be tied fast with anchor straps but yes pretty much it needs to be freestanding completely separate from the structure. Proper clearances on external chimneys are very rare I would say maybe 5%. But internal chimneys i have only ever seen one.

Does this mean that almost every builder is violating code when they abut the framing right against the masonry, or does this apply only to woodburning appliances, not to open fireplaces?

 

[Sain6815]

Does this mean that almost every builder is violating code when they abut the framing right against the masonry, or does this apply only to woodburning appliances, not to open fireplaces?

The code I just read basically said that you have to have 2" of clearance from all framing and trim should have fire flashing.

I believe I read that exterior chimneys have lesser requirements. I don't personally see many new homes being built with interior chimneys and I believe this code for clearance was added in the past decade.

 

[bholler]

Does this mean that almost every builder is violating code when they abut the framing right against the masonry, or does this apply only to woodburning appliances, not to open fireplaces?

Yes that is what it means. It also means the vast majority of inspectors don't know the actual code requirements when it comes to chimneys.

 

[bholler]

The code I just read basically said that you have to have 2" of clearance from all framing and trim should have fire flashing.

I believe I read that exterior chimneys have lesser requirements. I don't personally see many new homes being built with interior chimneys and I believe this code for clearance was added in the past decade.

Yes exterior chimneys only need 1". And it has been code for over 20 years now.