Hello. I'm a newbie here. I'm overhauling my fireplace & installing an insert. I'm planning on purchasing a Morso 5660 flush mount wood burning insert. My fireplace opening is 35 1/8" W x 29 1/2" H. The Morso 5660 is 30 3/8" W x 23" H so I need to reduce the opening. I'm thinking I can just buy fire bricks & high temp mortar and build up the base and sides. I'm going to be plastering over all of the face with Structo Lite anyway, so it won't be seen? Am I on the right track or is this DIYer in over his head? P.S. I could forgo the opening reduction & get the larger wide trim making overall insert 40" W x 33" H but that would dwarf the window in 10" of cast iron on ea side & I don't like the look. Thanks so much for your help!
How to Reduce Fireplace Opening
- Thread starter CozyCabin
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No reason you cant do that. you could use regular brick and mortar to for that matter
Wow! Really?! That would be fantastic. Thanks so much for your help! My wife was convinced we'd need to hire a mason and it would cost a fortune. Could I use quickrete as mortar?
I want to "float" the insert so will need a few layers of bricks on the bottom. For the base layer, I read somewhere that it's better to use sand as mortar. Is that true? Thanks again for your input. I really appreciate it.
You could also have a surround custom made for your opening. Will make future access to the insert easier.
Is that insert just for ambiance and some supplemental heat? Don't forget to install a block-off plate: https://www.hearth.com/talk/wiki/make-a-damper-sealing-block-off-plate/
Is that insert just for ambiance and some supplemental heat? Don't forget to install a block-off plate: https://www.hearth.com/talk/wiki/make-a-damper-sealing-block-off-plate/
Thanks for your feedback! We'd like the insert to serve as main/supplemental heat. Our house is a single story cabin. It's about 1100 sq ft. We're on propane for our forced air heat up here in the mtns and the cost of the propane is outrageous so we'd like to cut that cost down significantly with the insert.
How cold does it get in your area and how well is your cabin insulated? The insert only has a 1.5 cu ft firebox. It may be able to heat your space but I doubt you will get more than 5 to 6 hours of heat from it. Not sure how keen you are on getting up in the middle of the night to feed it.
Some other points:
How tall is your chimney and what does the manual say about minimum height of the flue? Since you are at a higher altitude you may need more than the minimum for good draft.
How many cords of dry wood (<20% internal moisture) do you have ready for this winter?
If you where modifying it to be used as a fireplace i would say use firebrick and refractory mortar but since you are changing it to fit an insert it doesn't matter. As far as the floor traditionally the floor brick would be set on a sand bed but it really doesn't matter you can do it either way. I personally hate quickcrete mortar but it will work i just prefer to mix my own i don't find that quickcrete works very well.
I did look at that trim kit but thought it made the window look too small. Thank you for your help, though! Really appreciate it!
Thanks for your reply. You raise some great points. I hadn't even considered the altitude. We're at 6500' elevation. It gets to a low of about 25 degrees. Very very rarely into the upper teens.
I'm uncertain of my chimney height.
We don't have any wood yet!!
Do you know of another flush mount insert with a larger firebox that would provide longer burn times? We also considered the Osburn Matrix.
That's a really smart idea! We're just plastering it white so that's a possibility. Thanks for the idea.
Great. I can't tell you how helpful this is. How much of an overlap should the frame create on the face of the fireplace? Is there a minimum amount required to create the appropriate flange effect? Would 1" be enough?
Quite honestly any overlap will be fine but 1" sounds pretty good. That overlap is not going to seal anything you just want enough overlap that you cant see a gap
kennyp2339
Minister of Fire
Try to figure that one out. You may need about 20 ft to get good draft which could mean the chimney needs an extension with class A. Does the Morso say anything about minimum chimney height?
Another problem. Check this post for options to get through the first winter :https://www.hearth.com/talk/threads/worried-about-wood.144682/#post-1951186
I would also order ~3 cords of wood as soon as possible to stack that up for drying. That way you should have at least decent wood the next winter.
Overnight burns usually start around a firebox size of 2 cu ft. The Matrix has 2.4 and would therefore qualify. Other options: Pacific Energy Neo 2.5, Lopi Flush Wood Plus, Regency CI2600, Quadrafire Grand Voyageur, Jotul C450
Now, some of those are rather large and may get a bit hot for your space and climate. You may need to regulate your home temperature by opening a window at times.
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