Boiler shed R Value for insulation

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goosegunner

Minister of Fire
Oct 15, 2009
1,469
WI
How well do you guys insulate your boiler shed walls and ceiling?

Mine will be R22 walls

Not sure about ceiling yet

Vented soffit and ridge

gg
 
I do not have an outdoor boiler but if I did I would put at least R30 in the roof.
I used some radiant foil on this place I am in now and it works great with only R19 in the walls. I am really impressed with the stuff.
Side note, out here we can not vent our soffits because it will pull wild fire into the roof system.

Erik
 
goosegunner said:
How well do you guys insulate your boiler shed walls and ceiling?

Mine will be R22 walls

Not sure about ceiling yet

Vented soffit and ridge

gg

Should be fine. My walls are R-19, ceilings the same, but it inside a 2 story garage
 
I'm putting R-19 in the walls, fiberglass with a plastic vapor barrier over that then drywall. The cieling will be cellouse. About R 17 on the eave edges and about R-60 in the middle. Used 2 x 6 rafters so I can only get so much in the edge. Then my storage will be insulated to around R - 50 on sides and R 80 on top. Probably overkill on top of storage ,but just the way it will work out. I will probably have to crack a window while boiler is running for air, then shut it when done.
 
I'm putting R-19 in the walls, fiberglass with a plastic vapor barrier over that then drywall. The cieling will be cellouse. About R 17 on the eave edges and about R-60 in the middle. Used 2 x 6 rafters so I can only get so much in the edge. Then my storage will be insulated to around R - 50 on sides and R 80 on top. Probably overkill on top of storage ,but just the way it will work out. I will probably have to crack a window while boiler is running for air, then shut it when done.
 
I normally would use cellulose in the ceiling to. Looking at my attic there just is not a lot of room up there with 4/12 pitch on a 12X16 building. Thanks for the feedback.

Whatever I end up with I guess it will be better than my OWB with 2" of spray foam sitting outside on the edge of a 60 acre field!


gg
 
I have 2x4 walls in my shed with r-13 insulation and I used R-13 on ceiling also. Plan on adding more but that's it for the time being. I don't have my boiler fired up yet(This weekend looks first fire) but I have a bucket with a 1/2" of water in the shed the last two days. Both nights the temps were in the low 20s and it still didn't freeze. So if your doing R-22 you should be fine. I also figure once stack is hot the shed should stay toasty.
 
I have 2x6 walls with R-19. I furred out the 2x12 rafters so I could insulate with 12" R-38. I wanted to trap as much heat as practical to minimize temp differential between boiler and room temps which should slow stand by losses.
 
Only have R- 5 Dow board under the pole bard steel. But I also have a 1.5 x 2 foot vent hole in the side for combustion air. It's always nice and warm in there, little heat loss, I'll just throw in another log.
 
I currently have R-19 fiberglass in the side walls and ceiling. Future plans are to add blown insulation in the walls and allot in the ceiling. I'm getting large ice-dams on the roof when I burn the boiler. I currently use a roof shovel after it snows before I fire up the boiler to try and prevent this as I don't want water backing up through my shingles. Its just like a house, more insulation in the building to keep the heat in the building. I would only be really worried about heat loss from the roof to prevent ice-dams as that is really hard on roofs. My boiler room will get into the high 80's when I really have the boiler burning hard, that's allot of temp difference from the outside air.
 
I have metal roof so ice dams should be minimal.

I got the the Supervent chimney installed yesterday, just in time because we got 4 inches of snow last night.

Insulation this weekend, I think I will go R30 batts.

gg
 
I insulated with what fits: R-13 in the 2x4 walls and R-19 in the 2x8 ceiling (I have an attic with a floor). It is a shed after all and I am not living in there! No matter what you insulate, you should probably have some freeze protection electric in case you leave for a while or can't build a fire for a time for some reason. If the boiler is running it will be plenty warm. Remember, you are intentionally pulling lots of cold air into the building while it is running. Insulation doesn't matter much in that case.
 
This season I'll keep the home fires burning to protect the WB. But for next season I'd like to incorporate a thermostat in the shed so if temps get near freezing, the primary pump will circulate oil supplied heat to the shed. Typically the primary turns off if the WB temp drops below 150 . but I'll manipulate the controls to compensate. I like tweaking!
 
Hunderliggur said:
I insulated with what fits: R-13 in the 2x4 walls and R-19 in the 2x8 ceiling (I have an attic with a floor). It is a shed after all and I am not living in there! No matter what you insulate, you should probably have some freeze protection electric in case you leave for a while or can't build a fire for a time for some reason. If the boiler is running it will be plenty warm. Remember, you are intentionally pulling lots of cold air into the building while it is running. Insulation doesn't matter much in that case.

The plan will be electric heater eventually. My brother has a simple Milk house heater in his rabbit barn. It is controlled by a thermostat switch. It easily keeps it above freezing.

My logstor is below the frost line and both ends are in a heated space. I will be able to travel in the winter and not worry about my system.

gg
 
Last year we left on December 2nd for a 10 day trip to Disney in Florida. What I did was run the tanks all the way up to 190ish and then turned down the house to 50 degrees. About 4 hours before we came home I had someone turn the house back up to 72 degrees and the house was warm when we got back, but the tanks were all down to 110 at the top so I don't know how low they got before the house got turned back up but from 50 to 72 would be allot of BTU's. I do know that the boiler room was cool, but never close to freezing after the 10 days without a fire in the boiler.
 
sdrobertson said:
I currently have R-19 fiberglass in the side walls and ceiling. Future plans are to add blown insulation in the walls and allot in the ceiling. I'm getting large ice-dams on the roof when I burn the boiler. I currently use a roof shovel after it snows before I fire up the boiler to try and prevent this as I don't want water backing up through my shingles. Its just like a house, more insulation in the building to keep the heat in the building. I would only be really worried about heat loss from the roof to prevent ice-dams as that is really hard on roofs. My boiler room will get into the high 80's when I really have the boiler burning hard, that's allot of temp difference from the outside air.

Glad you brought up the ice dams. I was thinking about putting shingles on the boiler shed roof ,but I think I will probably go steel for this reason. Guess I better order my high temp silicon chimney boot.
 
I am going with 2x6, mainly because of cost. I was looking at SIPS. But a lot more pricey.

The problem with all these numbers is that they are not truly comparable. If you have wood framing you have bridging through the studs, it has to be a very tight building for loose insulation top provide that level.

The Garn manual has a vertical duct for air input, a sort of air trap even though most of the combustion air comes from outside.

You can use staggered framing to avoid the bridging, I am going to get somebody else to build it and the people I have spoke to looked blank when I mentioned that.

The tricky bit is the door, I ned a small garaged door to get the wood in, you can get insulated doors but that still seems the point of weakness.
 
I split my shed into two parts - 6x12 boiler room and 10x12 wood room. Your wood won't mind getting cold so I would not worry about an insulated garage door. I have a 3 foot entry door from the outside into the boiler room, a 3 foot door into the wood area from the boiler, and an 8 foot outside opening (to be a door, now just a tarp). I also have a window in the boiler room and two windows on opposite sides in the wood room.
 
I had SIP scraps (well really big scraps for the most part) left over from building our house so I used those to build my boiler shed. Works great it's toasty warm in there. The outside cat that used to live in a freezing barn now is living it up in +80* comfort. But like some one else said when the boiler is running there is a lot of make up air coming into the shed (purposely left a large gap under the door to the wood pile) so don't think it makes too much sense to go crazy.
How have other people delt with the necessary gap around their double wall pipe where it goes thru the ceiling? If it weren't for that gap I wouldn't melt any snow off the roof but a lot of heat escapes thru there. I have a metal roof over the SIPs sitting on 2x4 purlins.
Bob
 
Hunderliggur said:
I split my shed into two parts - 6x12 boiler room and 10x12 wood room. Your wood won't mind getting cold so I would not worry about an insulated garage door. I have a 3 foot entry door from the outside into the boiler room, a 3 foot door into the wood area from the boiler, and an 8 foot outside opening (to be a door, now just a tarp). I also have a window in the boiler room and two windows on opposite sides in the wood room.

I built a small model to work out the flow. The building has no windows on the north, where the wind comes from, a door and a window on the west side and the 'garage' door on the south side.

We have serious wind issues here, blows the snow away but sometimes to where you do not want it. So I wanted 3 or 4 cords to hand for the very worst weather and the rest can be stacked on the south side of the building.

During the summer it would give me a work area.

BTW I am anticipating 50 cords a year, so a lot to shift.
 
I started today, I am doing two layers of R19 in the attic. The are perpendicular to each other so the joints are covered.

gg
 
This might be a little off topic but, are these building you guys are talking about housing an indoor boiler outside? If so sounds interesting. You could get a proven boiler at a great price, spend some money on a building and be able to leave in the winter and not worry about things freezing.

If this is what you guys are doing I have some more questions.......
 
BHetrick10 said:
This might be a little off topic but, are these building you guys are talking about housing an indoor boiler outside? If so sounds interesting. You could get a proven boiler at a great price, spend some money on a building and be able to leave in the winter and not worry about things freezing.

If this is what you guys are doing I have some more questions.......

That is what I am doing, I get the impression that many more people put them in an outside building that put them in the building to be heated.

You would still need to address the freezing issue, there are various solutions depending on the configuration.
 
BHetrick10 said:
This might be a little off topic but, are these building you guys are talking about housing an indoor boiler outside? If so sounds interesting. You could get a proven boiler at a great price, spend some money on a building and be able to leave in the winter and not worry about things freezing.

If this is what you guys are doing I have some more questions.......

Exactly, Here is a picture. I Just hung the drywall today, tape tomorrow.

Boiler goes in the front 12X16 building and the 1000 gallon tank is in the 6X20 enclosed lean to directly behind it.


gg
 

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