I recently bought a used St Croix York pellet insert rated for ZC installation and will be installing it in a maufactured fireplace. The existing flue pipe is a Preway 8" ID flue. I will be using 4" pellet vent, probably Excel. In an effort to keep the existing flue pipe as cold as possible (for ice dam reasons), I have been considering insulating the vertical pellet vent pipe with ceramic (cerawool) insulation by wrapping it with insulation help in place with wire mesh, probably chicken wire. The vertical vent will be about 20 feet, plus or minus. I understand it will draft like crazy. Will it damage the pellet vent in any way? Will the gaskets get too hot? McMaster-Carr sells the cerawool blanket in 24" wide X 25' rolls for less than $30. I've heard of wrapping the flex behind the stove with cerawool but haven't see much for wrapping the flue. TIA.
Thoughts on insulating pellet vent pipe?
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SmokeyTheBear
Minister of Fire
Thanks for the quick reply. I understand that the flue temp is a lot lower but I didn't burn the fireplace at all last year and only occasionally in previous years. I still had bad ice dams. I will be firing the pellet stove 24/7 so I would be putting more heat into the attic space on a continuous basis which is why it might aggravate the ice dam issue. The cooler I can keep the old fireplace flue, the better. I expect I may still have ice dam issues but I want to minimize the contribution from the pellet stove. The real issue with ice dams is the construction of the house. Aside from selling this shack, I've tried to do everything I can to to reduce the problem, I just don't want to go backward. I hope this clears up my motive for considering insulation. Thanks again for the input.
mepellet
Minister of Fire
Bioburner
Moderator
SmokeyTheBear
Minister of Fire
Catherdral ceiling, 2 X12" roof rafters, insulation and baffles. The insulation is probably 10" thick from what I've seen. I'm not due for a new roof and I don't want to tear out the ceiling. I've reworked the insulation baffles and sealed up holes in the drywall. The house has continuous ridge vent (Cobravent). Not much I can do but keep the bottom of the roof deck as cold as possible. The key to ice dams is insulation and ventilation as you guys have mentioned. There is plenty of insulation but the ventilation wasn't very good. Some of the insulation was right up to the bottom of the deck because the builder used cheap 16" styrofoam baffles for a 24" spacing. I addressed that as best I could when I had the siding and soffits done. I wanted to isolate the flue chase from the attic space but that would've required completely blocking off soffit ventilation for two 24" rafter "bays" directly above the chimney. Probably not a good idea. My next best option is to keep the flue pipe heat out of the attic. Maybe I'm getting too concerned about the amount of heat it will put in the attic. I just don't want to make my problem worse. We never had enough snow last year to see if the additional air circulation under the deck made a difference. We'll find out this year once I get some snow on the roof. BTW, my roof will hold a foot of snow on it for weeks at a time. The problem is the ice dam at the eave will be a foot thick after a month. I use ice cables so I don't have water leaking in the house but the ice slabs coming off in the spring would kill ya dead.
SmokeyTheBear
Minister of Fire
What was your primary heat and how was it vented?
And what was the change in your soffit's opening area compared to that before the change? Just a little in each section can make a large difference to the roof deck.
Do you have any can lights in the ceiling?
And what was the change in your soffit's opening area compared to that before the change? Just a little in each section can make a large difference to the roof deck.
Do you have any can lights in the ceiling?
Hi Smokey,
Primary heat is oil / hot air vented through a brick and tile flue in the back of the house. I don't know the difference in open area in the soffit vents but the old stuff was small louvers about 4" wide along the eves. When the siding and soffits we done it was replaced by the perforated stuff the full width of the soffit, about 8" wide. When the siding was done I talked to my contractor about my ice dam problems and asked him to make sure the insulation hadn't settled or blocked the soffit vents. I also had him bend up sheet metal baffles that fit the spacing between the ceiling joists so the insulation wasn't against the deck. No can lights in the catherdral area, just (2) track lights. I do have two recessed can lights in the hall upstairs and I have purchased new, sealed can lights for use with direct contact insulation to replace them. My upstairs bathroom vent fan was also vented to the attic so I had a wall vent installed with the siding and ran flex to the vent. There is a lot of batt insulation in attic, at least a foot. I'm doing about everything I can think of to avoid the ice dams. It is very common to see them in my neighborhood as there are a lot of contemp's with cathedral ceilings and they were all tossed up in the mid-80's. I love the house but it's built like crap.
How's that IPA coming along? I'm sipping an Old Chub scotch ale as I type. I need to make a batch. My last one was a Stout. Not bad, but a little band-aid'y. Looked good, though. Beautiful, thick head.
Primary heat is oil / hot air vented through a brick and tile flue in the back of the house. I don't know the difference in open area in the soffit vents but the old stuff was small louvers about 4" wide along the eves. When the siding and soffits we done it was replaced by the perforated stuff the full width of the soffit, about 8" wide. When the siding was done I talked to my contractor about my ice dam problems and asked him to make sure the insulation hadn't settled or blocked the soffit vents. I also had him bend up sheet metal baffles that fit the spacing between the ceiling joists so the insulation wasn't against the deck. No can lights in the catherdral area, just (2) track lights. I do have two recessed can lights in the hall upstairs and I have purchased new, sealed can lights for use with direct contact insulation to replace them. My upstairs bathroom vent fan was also vented to the attic so I had a wall vent installed with the siding and ran flex to the vent. There is a lot of batt insulation in attic, at least a foot. I'm doing about everything I can think of to avoid the ice dams. It is very common to see them in my neighborhood as there are a lot of contemp's with cathedral ceilings and they were all tossed up in the mid-80's. I love the house but it's built like crap.
How's that IPA coming along? I'm sipping an Old Chub scotch ale as I type. I need to make a batch. My last one was a Stout. Not bad, but a little band-aid'y. Looked good, though. Beautiful, thick head.
SmokeyTheBear
Minister of Fire
I haven't cracked open a bottle of either yet so I don't know how they are. My cider is slowing down I may get that into bottles sometime this week. I don't know how much glug gluging the boss will tolerate so I'll likely take a break before the next batch.
Ice dams can be a real pain, I have a partial Cathedral ceiling it covers the living room and dinning area portion of the great room. My soffit is the full width perforated variety and I do not get any ice damming but there has to be an outlet up above to move the air or it will gradually warm. I have two bathroom vents that go through the attic and vent out the soffit The other vents go out the side of the house. Usually have a lot of snow on the roof, I remove it when it gets north of 3 feet deep. On one side of the house I have to move the snow twice when I remove it from the roof. There is a deck that runs the length of the house at what is a normal second story height. I had the ice dam issue on one house that got taken care of when I finished off what was the attic.
Can lights allow a lot of warm (and frequently moist) air into an attic as can a poorly sealed attic entry area.
Don't get me started on house construction.
Ice dams can be a real pain, I have a partial Cathedral ceiling it covers the living room and dinning area portion of the great room. My soffit is the full width perforated variety and I do not get any ice damming but there has to be an outlet up above to move the air or it will gradually warm. I have two bathroom vents that go through the attic and vent out the soffit The other vents go out the side of the house. Usually have a lot of snow on the roof, I remove it when it gets north of 3 feet deep. On one side of the house I have to move the snow twice when I remove it from the roof. There is a deck that runs the length of the house at what is a normal second story height. I had the ice dam issue on one house that got taken care of when I finished off what was the attic.
Can lights allow a lot of warm (and frequently moist) air into an attic as can a poorly sealed attic entry area.
Don't get me started on house construction.
I hear ya on moving snow twice. 80% of what gets shoveled off my roof has to be moved again. I will put a tarp down on my driveway next time. The stuff is dense after it falls 15 feet after consolidating on the roof. The two reccessed can lights in the upstairs hall are vented. Those are the two I want to replace with sealed units. The attic access stinks. I had to add it as there was NO access when I bought the house. I added the access so I could add ceiling fans and an electric skylight. It is insulated, gasketed and magneticly help in place. I don't know how good that Cobravent ridge vent works. It's like a coarse plastic material with a lot of open area if it's installed correctly. If I have problems this year I'll look at that again. Thanks for your replies Smokey. Sounds like we have similar construction. Do you get ice dams at your cathedral ceiling eave?
Ironhorse74
Member
I have a different opinion here. I was a Preway dealer back in the 80's. Preway had some tremendous problems. Mostly expansion issues after a chimney fire. If it were me doing the job, I would drop pellet vent down through the existing chimney. If itt dows now have any offsets, this should be easy. Put a 4 or 5 foot section of flex in the firebox. I might even consider putting a block off plate at the damper and then insulating around the pellet vent.
Just my .02 your mileage may vary.
Just my .02 your mileage may vary.
That's pretty much my plan. I am just making sure the pellet pipe seals won't get too hot if I insulate the whole pipe inside the old Preway flue. I think I can run the 4" rigid pellet vent all the way to the damper area. It's a straight shot to the cap. I would remove the damper and install a block off plate with some rock wool above it. I would run flex wrapped with cerawool inside the old firebox to the top of the cleanout tee at the back of the stove. I don't care much for the Preway fireplace.I would say that it's better than nothing....but it's not. The only saving grace is that I can convert it to something useful, like a pellet insert.
SmokeyTheBear
Minister of Fire
The seals should be able to stand the pipe being wrapped without any issue. The exhaust temperature is below 475
which is below the silicone rubber seals in ICC pipe at about 475 your exhaust fan will thermal off causing a vacuum fault resulting in the stove heading for shutdown.
Go ahead it is your dollars.
which is below the silicone rubber seals in ICC pipe at about 475 your exhaust fan will thermal off causing a vacuum fault resulting in the stove heading for shutdown.Go ahead it is your dollars.
Do them make them with 50 foot long handles? It's a long way to the peak fom the ground in the front. My garage is under the house. It's about 18 feet vertically to the eave from the driveway. I've always tied off and used a snow scoop from the top down. I guess I could try just raking the eaves then up the roof about 5 feet. Maybe I could get away with a 25-30 foot handle.
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