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
Mine is not insulated, and it gives no problem. But whereas yours will be inaccessible, I would just do it and never wonder if I should have.
Yes, you should. Mine iced up on the regular until I wrapped it in some foam tape. I only needed to do about 2', but since you won't have access, do the whole shebang like bushpilot suggested.
I agree with the others, an ounce of prevention and all that You certainly don't want to get the hearth and stove installed, and then run into problems Question.. is the inlet "critter protected"?
If it was mine, I'd put either a section of straight aluminum or Galv pipe pitched down to daylight, seam up. Wrap like papadave mentioned. That flex has too many nooks that could hold moisture should it condense. Oh, almost forgot...
Ok, I have a question can these OAK condense on the inside? Say a conditioned house and summer heat getting inside the duct...
Yes! If you have condensation you will get corrosion. Insulation and a vapor barrier are highly advised.
I built a similar OAK through the elevated hearth. Rip out what you did and install 4" rigid duct all the way up through the finished floor of the hearth. Use a short flex section only to connect the stove to the stub. I actually used a can of expanding foam to both lock the duct in place and to insulate it. Make sure you strap this duct work down so it doesn't move. My first elevated hearth was with flex and I believe it is a bad idea. You can't get in there to replace it.
