Limitations with Pre-Fab Chimneys

[gliebisch]

I have a gas-only fireplace at present that is just vented to the outside. I wish to convert it to woodburning and that will require adding a pre-fab chimney that extends above my second floor (on an outside wall). The reason for the pre-fab chimney is 1) cost and 2) all other chimneys in the subdiv are prefabs so I suspect the strict neighborhood association will want it to conform. There are models of my house built in this neighborhood that have a prefab chimney where I have the vent only.

My question is: with a prefab chimney, will I be limited to the size firebox I can install? Originally I had thought that prefab chimneys were only for GAS fireplaces, but my reaseach has indicated that may not be true. Would like to know the constraints that a prefab chimney would place on the fireplace design.

GaryL

 

[basswidow]

By prefab - are you referring to a framed and siding chimney chase? or you mean a prefab fireplace fireplace like a heatilator with a gas log? Many "looks only" gas fireplaces, the bumpout chase doesn't go beyond the 1 floor and is vented out 90 degrees.

"My question is: with a prefab chimney, will I be limited to the size firebox I can install? Originally I had thought that prefab chimneys were only for GAS fireplaces, but my reaseach has indicated that may not be true. Would like to know the constraints that a prefab chimney would place on the fireplace design." The chimney shouldn't not limit the firebox size. The size of the bumpout might. What's the foot print and can you make it bigger? The framing foot print will dictate what you can put in place of it, whether it can accomodate the weight and size of the zero clearance fireplace you want to install. The chimney is usually a 6 inch HT flue for many different types and desiqns.

Measure your footprint first and look at what you want to put in there.

Are you wanting a fireplace to burn wood for looks and an occasional fire or one to produce heat and burn alot?

If you can extend the Chimney flue chase to the appropriate Roof level - it can house a HT class A flue and you can install several options. One would be a zero clearance fireplace (stove) like my Kozyheat Z-42. They are specifically made for easy replacements of "prefab" heatilator fireplaces. They are zero clearance - you can but them right up to wood framing. There are other makers as well like the RSF Opel.

These zero clearance fireplace stoves put out great heat and are eye pleasing as well.

If your HOA will allow the extension of the chimney and allow you to have a wood stack..... go for it.

 

[begreen]

There's nothing wrong with a proper class A chimney, but there is a problem with converting a gas direct vent fireplace to wood. That's a no-go. I think you may need to rethink this plan and look at all options.

 

[DAKSY]

There's nothing wrong with a proper class A chimney, but there is a problem with converting a gas direct vent fireplace to wood. That's a no-go. I think you may need to rethink this plan and look at all options.

+1. You're gonna hafta start from the floor & replace EVERYTHING,
FIREBOX included - not just the vent. There's NO WAY a gas box with
a horizontal wall vent is designed or rated to safely burn wood.

 

[gliebisch]

I fully understand that I may have to replace the firebox and certainly don't plan to convert to wood and keep the vented system. I only want a fireplace for occasional woodburning fire and atmosphere and definitely not for heat, so I am not considering a stove. By prefab I mean siding to match the house as opposed to brick. It also eliminates the need to pour a concrete footer for a masonry FP, as the lightweight prefab can just be cantilevered out.