New chimney liner/fireplace insert questions.

[Cab4you26]

Hello all!

I’ve been reading for a few months about what I need to do a liner installation in my 1950s 1300 sq. ft. home but I still have a few questions. My home has a 15’ chimney from the hearth floor to the top of the chimney. The fireplace insert we ordered (not here yet) is the Pacific Energy Super LE, which the manual states needs that minimum to work properly. So I’m right on it with those measurements and I hope it will work well that way.

My chimney clays are 7x7 squares. I ordered a 6” chimney liner with 1/4” insulation from Rockford Chimney Supply. I had initially planned on ordering 1/2” insulation but when ordering it Rockford stated the 1/2” insulation adds 1.5” total and the 1/4” adds 3/4” total. I’m not sure why that is. So I ordered the 1/4” to be sure it would fit down my chimney. My concerns are if what I’m installing will meet UL 1777. I read to be up to that standard it has to be 1/2” so I’m a bit worried about that. I’m installing this with a friend who’s a masonry contractor and planning to fill in with masonry at the top and where the liner comes into the throat of the chimney.

Is the difference in insulation a cause for concern or am I overthinking this?

To provide context, we are going to be using this as supplemental heat to cut costs on buying over the winter.

 

[Supersurvey]

Im sure the experts will answer soon but could the stove run on a 5.5 inch liner?

 

[Cab4you26]

I

Im sure the experts will answer soon but could the stove run on a 5.5 inch liner?

The stove requires a 6” liner. It’s actually 6.5” OD. So I know with the 1/4 insulation it’s going to be a tight fit.

 

[EbS-P]

You are req it your code to have the 1/2” insulation if your masonry chimney does not have the required clearance to combustibles 1” exterior chimney 2” if it’s an interior. This means framing and roof decking too. Most don’t. So we add 1/2” of insulation and now we meet code. 1/4” is safer but code is binary.

I don’t see any need to add masonry. An insulated blockoff plate will seal everything well enough

The only way to get the 1/2” insualton to fit down a 7x7 to break out the clay flue tiles.

Im sure the experts will answer soon but could the stove run on a 5.5 inch liner?

It’s al ready at minimum height and I would guess the manual is very clear that 6” is required. So it’s not a good solution.

 

[Cab4you26]

You are req it your code to have the 1/2” insulation if your masonry chimney does not have the required clearance to combustibles 1” exterior chimney 2” if it’s an interior. This means framing and roof decking too. Most don’t. So we add 1/2” of insulation and now we meet code. 1/4” is safer but code is binary.

I don’t see any need to add masonry. An insulated blockoff plate will seal everything well enough

The only way to get the 1/2” insualton to fit down a 7x7 to break out the clay flue tiles.

It’s al ready at minimum height and I would guess the manual is very clear that 6” is required. So it’s not a good solution.

In what way do you mean 1/4” is safer?

The code is one thing I don’t understand fully, or atleast a bit more tedious to determine if I’m okay in that respect. It’s an interior chimney so 2” to combustibles, but measuring this is a bit more difficult. I guess I need to hop on the roof and take the outside measurements of the chimney and account for the 7x7 squares and then figure up how close that is to the combustible material.

Edited to add but it says 2” air gap between combustible material and exterior face of chimney. I highly doubt I have that interior-wise and I don’t see how that’s possible really with where the roof meets the exterior of the chimney anyway.

 

[bholler]

I

The stove requires a 6” liner. It’s actually 6.5” OD. So I know with the 1/4 insulation it’s going to be a tight fit.

Get a midweight or heavy wall liner and it's a little under 6.25".

I would remove the clay and do it right with 1/2" insulation. The 1/4" stuff is only for liquid fuel. Did you tell Rockford it was for a woodstove?

 

[Cab4you26]

Get a midweight or heavy wall liner and it's a little under 6.25".

I would remove the clay and do it right with 1/2" insulation. The 1/4" stuff is only for liquid fuel. Did you tell Rockford it was for a woodstove?

I wasn’t in touch with Rockford when I made the order. I just selected everything from their drop down menu. I’ll call them today, though. I have plans to get this liner done on Friday so I’ll make sure I have everything I need to do it right or I’ll reschedule. It looks like Rockford has a chain breaker tool that hooks to a 1/2 impact for removing clays. I can make something similar….or is there a better way to remove them?

 

[kborndale]

In what way do you mean 1/4” is safer?

I believe he was saying 1/4" is safer than no insulation, not safer than 1/2".

 

[Cab4you26]

Just an update but I called Rockford and ordered the 1/2” insulation and will send the 1/4” back when the job is finished. Thanks everyone for the help!! I will post pics along the way.

 

[Cab4you26]

So we didn’t get finished today. Getting the terra-cotta tiles out was a hard win. I ended up making a sharp edge on a 5ft and 10ft piece of rebar. Heated it up and quenched it and then welded a nut on the other side. It took about 6 hours to get all the tiles out. Then we prepped the liner. That’s all we got done. Hopefully next time we will get it finished 😅. I will say this probably isn’t a job I would’ve wanted to tackle if my chimney was much longer. I think it would’ve gone much quicker if I’d rented the rotary chain tool from Rockford.

 

[Cab4you26]

Well we finished up today minus adding the insulation/firebox cover. I’m going to wait till I get the insert to do that. The liner went in easy but I can’t get it to bend where I need it to in the firebox. I was thinking I could trim it to have two 45s that connect to the stove? Any thoughts on that?

I can also see the terra cotta tiles for the oil heat from the inside of the chimney…should I try to cover that with brick/mortar or is it safe to leave alone? It appears to have been exposed the entire time.

 

[begreen]

Rockford chimney sells angled appliance adapters that will do the job. A 30º adapter may suffice here.



Was the liner wrapped in something to separate it from the mortar before it was cemented in? It needs room to expand and contract.

 

[Cab4you26]

Rockford chimney sells angled appliance adapters that will do the job. A 30º adapter may suffice here.

View attachment 301547

Was the liner wrapped in something to separate it from the mortar before it was cemented in? It needs room to expand and contract.

The liner was wrapped in 1/2” insulation. I hope they will allow it to expand/contract properly without damaging the mortar.

I think the entire mortared chimney top will need to be redone to mesh with the stainless cap. The silicone around the cap is already separating because the gap is so large. It’s also not level. I could tell the guy helping me, who’s a friend, wanted to be done so I didn’t push it, but I do want it to be done right. I also found out the company that initially redid the chimney top years ago just mortared over the bad chimney top and didn’t completely replace. I’m not sure if that standard procedure or not but yeah.