Pre-fab With Brick Chimney: Remove or Retro-fit

[BWD]

Recently purchased a 1970-built cabin in the woods with a pre-fab fireplace, make unknown until I visit the cabin in a few weeks. Old photos show the chimney is brick and later faced outside with native stone. Inside has an elevated stone hearth and native stone face with passive vent below the mantle; above it is a pine paneled wall. There are two louvered vents at floor level on each end of the heath. The terracotta flue is maybe 6x6 or 8x8 inches and in good condition as determined by a certified sweep that also replaced the frozen damper with a top damper. A small area on the metal liner at the inside back of the fire box is deformed. I've learned that this style of unit is well past its useful life and where wood framing was used, they are unsafe for other heating options. The 900 ft2 cabin is on a skirted crawl-space and insulated. There is also a small non-vented propane wall mounted heater. I'd like to use the fireplace/chimney for heating. To do so, does the pre-fab need to be removed or can it be modified to fit either an insert or a free standing stove? Is relining required/recommended? Is there anything I am missing or haven't considered?
Thanks

 

[begreen]

By the description, this sounds like it might be a heatform style fireplace. Sometimes these used to be called Heatilators. If so, a wood fired insert may be an option. Hopefully the flue is 8x8 ID that will facilitate a 6" stainless steel liner connected to the new insert.

 

[BWD]

Thanks for the quick reply. Now that you pointed it out, it’s identical to the fireplace at home except without the blower units on each side of the fire box. So there are tubes that direct hot air to the front vent above the hearth? I assume one or more need to be removed and the old damper too in order to connect to a new flue pipe. I checked and the flue is 13x13. Is a flue liner required/reccomended in this instance? Hoping to learn more about equipment and process before speaking with a local provider.

 

[begreen]

Yes, an insulated 6" liner is what is typically needed for most insert installs. Measure up the fireplace dimensions H, W, & D, top and bottom to see what will fit. What seasons is the cabin used? What temperature will the cabin be at first arrival? Does it have electricity?

 

[BWD]

The cabin is used year round, typically long weekends but also a week at a time in the fall. Last week with temps in the upper teens the inside temp was 30F. The prior owner installed the propane heater “to take the edge off”. Yes it has electricity.

 

[begreen]

Go as big as will fit. The Drolet Escape 1800 is a popular value insert that won't break the bank and will work on a shorter cabin chimney if this is a one story building.

 

[BWD]

Thanks again for your expertise and willingness to help. I looked at the 1800 and the 1500 and neither will fit. The fire box top tapers down to 16 inches at the back. Although both inserts don't require the full depth of the fire box (24-inches) when I calculate the height of the angled fire box at the depth of the insert the available height is short by about 0.5 to 1.0 inch. I'll remeasure more carefully to confirm this on my next visit. Assuming the height is correct, can the inner metal wall be cut to accommodate an insert? How large is the typical space between inner and outer metal walls? Assuming its not advisable to cut, what if anything changes if i go with a freestanding stove in the fireplace?

 

[begreen]

Yes, we have seen some of the backs of these units trimmed at the top to accomodate the insert. Note that the insert doesn't need to have a surround. It can be installed without one and can sit further out onto the hearth as long as the liner connection is still viable, though the hearth may need to be extended in some cases.