Cinder block chimney install

[pyrojoe]

Hi all, it's been a few years since I've burnt wood due to moving to a new place. I've been hoping to get a wood burning furnace installed in the basement and haven't gotten it done to this point (more questions coming on that). My first item of business is getting my chimney situation figured out. I currently have a cinder block chimney going from the basement, which is about 9-10" square i.d., with the wall of the block being about 4" thick. I have three questions that I know of right now.

1. There is no consistent clearance maintained on the outside of the chimney. There's actually been a room finished in the basement whose studs are within an inch of it. Am I ok with this if I install a 6" stainless insulated liner?
2. The chimney appears to have vented both a oil furnace, which is moved off, and a gas water heater, to be moved off. This will leave 2 holes that need to be patched. Any advice on specific material for doing this, and is this generally considered acceptable/safe?
3. The old furnace flue left a 6.5" hole, so ideally I could reuse it. The problem is it's about 6.5" down from the first floor joists. I know double wall connector pipe has a 6" clearance requirement. Is there a different requirement for vertical clearance for connector pipe (single or double)? I'm guessing I'll need to cut a new hole further down.

I appreciate your help!

 

[BlankBlankBlank]

I have three questions that I know of right now.

1. There is no consistent clearance maintained on the outside of the chimney. There's actually been a room finished in the basement whose studs are within an inch of it. Am I ok with this if I install a 6" stainless insulated liner?

Masonry chimneys require a 2" air space around them, per NFPA 211 table 7.2, column VIII for interior, residential brick or concrete chimneys. This does not change when a liner is used.

2. The chimney appears to have vented both a oil furnace, which is moved off, and a gas water heater, to be moved off. This will leave 2 holes that need to be patched. Any advice on specific material for doing this, and is this generally considered acceptable/safe?

Use concrete bricks which can be purchased at most home centers or masonry suppliers. They are low cost and easy to install. The key issue is maintaining the 4" chimney wall thickness which is a requirement for brick or concrete residential chimneys listed in table 7.2, column I of the NFPA 211.

3. The old furnace flue left a 6.5" hole, so ideally I could reuse it. The problem is it's about 6.5" down from the first floor joists. I know double wall connector pipe has a 6" clearance requirement. Is there a different requirement for vertical clearance for connector pipe (single or double)? I'm guessing I'll need to cut a new hole further down.

Single wall pipe clearance for residential solid fuel appliances is 18" minimum according to table 9.5.1.1, but UL listed appliances will specify engineered clearances. For double wall UL listed pipe, consult the manufacturers specs.

 

[bholler]

I have three questions that I know of right now.

1. There is no consistent clearance maintained on the outside of the chimney. There's actually been a room finished in the basement whose studs are within an inch of it. Am I ok with this if I install a 6" stainless insulated liner?

Masonry chimneys require a 2" air space around them, per NFPA 211 table 7.2, column VIII for interior, residential brick or concrete chimneys. This does not change when a liner is used.

2. The chimney appears to have vented both a oil furnace, which is moved off, and a gas water heater, to be moved off. This will leave 2 holes that need to be patched. Any advice on specific material for doing this, and is this generally considered acceptable/safe?

Use concrete bricks which can be purchased at most home centers or masonry suppliers. They are low cost and easy to install. The key issue is maintaining the 4" chimney wall thickness which is a requirement for brick or concrete residential chimneys listed in table 7.2, column I of the NFPA 211.

3. The old furnace flue left a 6.5" hole, so ideally I could reuse it. The problem is it's about 6.5" down from the first floor joists. I know double wall connector pipe has a 6" clearance requirement. Is there a different requirement for vertical clearance for connector pipe (single or double)? I'm guessing I'll need to cut a new hole further down.

Single wall pipe clearance for residential solid fuel appliances is 18" minimum according to table 9.5.1.1, but UL listed appliances will specify engineered clearances. For double wall UL listed pipe, consult the manufacturers specs.

This is all correct other than an insulated liner does change the clearance requirements. It gives you zero clearance to the outside of the chimney

 

[Doc C]

Does the 4" block get rid of the need for a clay liner assuming someone does not reline the chimney? Or is it 4" of brick plus a clay liner?

 

[bholler]

Does the 4" block get rid of the need for a clay liner assuming someone does not reline the chimney? Or is it 4" of brick plus a clay liner?

The clay has nothing to do with it if there is a stainless liner.

 

[BlankBlankBlank]

This is all correct other than an insulated liner does change the clearance requirements. It gives you zero clearance to the outside of the chimney

This I did not find listed in NFPA 211. So, are you saying that UL listed liners specify this?

 

[bholler]

This I did not find listed in NFPA 211. So, are you saying that UL listed liners specify this?

Yes absoluyly. It is also in irc and nfpa211