Should I insulate the OAK duct?

[MAD777]

I'm building my home in New Hampshire with proposed corner installed woodstove on a, 16" high hearth. Pictured below is the OAK duct which will come in under the hearth. It will be inaccessible once the home is completed. On frosty mornings, which is nearly every morning throughout winter, there is practically ice formed on this duct. Note that the house is not currently heated and the concrete slab floor you see will have radiant heat in it.
The second picture is an artist rendition of the final product. My question is, should I wrap this duct in some form of insulation and if so, what material should I use?


Sent from my Pixel 2 using Tapatalk

 

[Rearscreen]

I see no pics.

 

[MAD777]

I see no pics.

I always miss something, LOL
Pics added to original post

Sent from my Pixel 2 using Tapatalk

 

[Rearscreen]

I get thin frost on mine but so little it isn't a problem.

 

[electrathon]

Yes, two reasons. When not running it is a seal between inside and outside of nothing more than a piece of aluminum. When the stove is running the cold air coming in (and drawing heat out of the room to go into the air inlet) will condense moisture on the tube possibly causing water damage in the long run. I can not think of any valid reason not to insulate it.

 

[Rearscreen]

I can not think of any valid reason not to insulate it.

Mold.

 

[jetsam]

I'd insulate it to prevent the water in the house from condensing on it.

Limiting airflow around the duct will also limit the amount of condensation, so a simple box o' bricks could help a lot.

 

[MAD777]

I keep going back and forth on the pros & cons. If I did insulate it, what should I use?

Sent from my Pixel 2 using Tapatalk

 

[zrock]

You could wrap with fiberglass pipe wrap. Or fill the void in the hearth with rocksol or how ever you spell that.. its fireproof insulation...

Sent from my SM-G950W using Tapatalk

 

[Bartman23]

I do mechanical insulation for a living. If theres gonna be any bend to it a piece of 2" thick flexible duct wrap sealed with foil tape would be your easiest option. Just dont pull it super tight and ensure your tape is rubbed down so it doesnt let go over time. Armaflex is also another good product for cold applications

 

[electrathon]

Mold.

Not sure I understand. Not insulating will promote more condensation. Condensation leads to mold. Not sure why that is desirable.

 

[Bad LP]

Insulate.

 

[Rearscreen]

Well, if you were to use fiberglass insulation, eventually mold could occur. A closed foam surround not so. One question, how far above the ground does your pipe terminate outside?

 

[Mnpellet]

What’s all the black on the floor?

 

[MAD777]

@Rearscreen The inlet is about 2.5 feet above grade on the outside.
As this is snow country, I will be keeping the area cleared.

Sent from my Pixel 2 using Tapatalk

 

[MAD777]

What’s all the black on the floor?

Good question. I'm going to the house today and will investigate. It's currently a construction site, so everything is dirty.

Sent from my Pixel 2 using Tapatalk

 

[Ludlow]

I insulated mine. Used fiberglass. Mine is exposed and straight out the back.

 

[Highbeam]

Rip that thing out and use actual metal duct inside the hearth. Its cheap, easy to insulate, and you won’t have to worry about replacing it like you would that silly flex line when some person or animal steps on the exposed chunk that is above your finished hearth. Only use flex above the finished floor between the duct snout and the stove.

Since this duct is under the finished hearth, the insulation can be combustible. Anything.

 

[Ludlow]

I used 4" snaptite on mine.

 

[MAD777]

What’s all the black on the floor?

It's gone today. I took the picture last week after we were having negative temperatures for several nights and teens for daytime highs. The spot is gone now. The last couple of days have been in the 50's with overnight above freezing. I suspect the discoloration was due to melted frost, actually a layer of ice, that I observed on the duct last week.

Sent from my Pixel 2 using Tapatalk

 

[Rearscreen]

slab floor you see will have radiant heat in it.

Hydronic radiant?