This is meant to help others while debating a new flue liner installation. I spent hours researching and reading before my upgrade and found a lot of people had similar questions. These are my findings at my home,
I am not an expert and do not claim to be one.
About 4 years ago I decided I wanted to add an insert in my fireplace. I live in a one story ranch built in 1959 that has a large central fireplace. It starts in the basement with block and goes up through the roof with a large open fireplace in the living room. The chimney contains a double flue, the other used to vent a boiler in the basement.
A friend of mine owns a hardware store and started selling fireplaces. He had an insert that was ordered and cancelled and been sitting for a year so he made me a nice deal to take it. My flue is 13 x 13 clay lined and needed a liner. He had a very heavy stainless flex liner that was 15' long and after some rough calculating we decided it would work. I asked about insulation and his thoughts were the fireplace is centrally located and should stay warm and not need to be insulated.
I removed the damper and did some cutting to enlarge the hole and went to the roof. It was cold and I was in a hurry and just wanted to be done. I slid the liner down the flue and realized my opening at the damper was snug and there was no way I was making the bends needed to get to the stove. Well an elbow and cussing we got that part done. Back to the roof and the liner was a foot short of clearing the top. solution was to add a section of single wall round to the flex and extend above the brick and end up with about 18 foot of liner (manufacturer called for 12' min).
Stove run fine and clean, yearly cleaning resulted in a cup of very fine creosote. Only problem was the stove liked to puke smoke every time you opened the door to add wood. When you first lit the stove you could leave the door wide open and it would draft like crazy but once you closed the door the problem started. I tried opening a window to allow air in but that made no difference. The problem was consistent for 4 years.
Fast forward to a couple weeks ago I was prepping for winter and had thoughts of insulating the flue to see if it would help. I researched pouring vermiculite down around the liner but talked myself out of it.
What I decided to do was tear out the liner and start over. I ordered a 20 liner with the proper termination adapter and insulation kit.
I cut out the damper opening larger and run the liner all the way to the insert. I used tin and insulation to properly close off the damper opening (before it was just insulation). I wrapped the foil faced insulation around the pipe and taped it off per the instructions. The top terminated at the clay with a deluxe terracotta cap that hinges open for cleaning. My overall height ended up being shorter at just 16 feet.
Well I have been burning all week and can report a big change. I can open the door at any time with no smoke pouring out. I have also noticed I can close the door sooner after lighting with out choking out the flames. So far i am very pleased.
Should you insulate your flex liner? I would say yes if you can as it has made a big difference for me.
Hope this helps someone in the future.
I am not an expert and do not claim to be one.
About 4 years ago I decided I wanted to add an insert in my fireplace. I live in a one story ranch built in 1959 that has a large central fireplace. It starts in the basement with block and goes up through the roof with a large open fireplace in the living room. The chimney contains a double flue, the other used to vent a boiler in the basement.
A friend of mine owns a hardware store and started selling fireplaces. He had an insert that was ordered and cancelled and been sitting for a year so he made me a nice deal to take it. My flue is 13 x 13 clay lined and needed a liner. He had a very heavy stainless flex liner that was 15' long and after some rough calculating we decided it would work. I asked about insulation and his thoughts were the fireplace is centrally located and should stay warm and not need to be insulated.
I removed the damper and did some cutting to enlarge the hole and went to the roof. It was cold and I was in a hurry and just wanted to be done. I slid the liner down the flue and realized my opening at the damper was snug and there was no way I was making the bends needed to get to the stove. Well an elbow and cussing we got that part done. Back to the roof and the liner was a foot short of clearing the top. solution was to add a section of single wall round to the flex and extend above the brick and end up with about 18 foot of liner (manufacturer called for 12' min).
Stove run fine and clean, yearly cleaning resulted in a cup of very fine creosote. Only problem was the stove liked to puke smoke every time you opened the door to add wood. When you first lit the stove you could leave the door wide open and it would draft like crazy but once you closed the door the problem started. I tried opening a window to allow air in but that made no difference. The problem was consistent for 4 years.
Fast forward to a couple weeks ago I was prepping for winter and had thoughts of insulating the flue to see if it would help. I researched pouring vermiculite down around the liner but talked myself out of it.
What I decided to do was tear out the liner and start over. I ordered a 20 liner with the proper termination adapter and insulation kit.
I cut out the damper opening larger and run the liner all the way to the insert. I used tin and insulation to properly close off the damper opening (before it was just insulation). I wrapped the foil faced insulation around the pipe and taped it off per the instructions. The top terminated at the clay with a deluxe terracotta cap that hinges open for cleaning. My overall height ended up being shorter at just 16 feet.
Well I have been burning all week and can report a big change. I can open the door at any time with no smoke pouring out. I have also noticed I can close the door sooner after lighting with out choking out the flames. So far i am very pleased.
Should you insulate your flex liner? I would say yes if you can as it has made a big difference for me.
Hope this helps someone in the future.
