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Old 10-23-2008, 02:50 PM   #1
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Adding insulation to only a portion of an attic?


I would like to know if it is beneficial to help warm up one room on my top floor by adding extra insulation to the attic above the room.

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The short version of the story is that there is one room that is colder than the rest, mainly because the door must be closed at night (8:30pm - 7am) so my daughter can sleep and not be disturbed by light and noise from the hallway in front of her bedroom door. The airflow in/out of the room is fine, and the window is sealed and not drafty. Last year we used a space heater but now that she's walking, and curious, I don't want to use a space heater because of possible burns/injuries to her.
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My attic is approx. 900 square feet, her room composes about 140-150 square feet of that area in one corner (furthest from the attic access hatch).

I haven't been up there to see what R value I currently have, but assume that it is the building code minimum of R-24ish at most (the house is 5 years old, cookie-cutter end unit townhome). We are in Ottawa, Ontario, an area comparable to upstate NY, Minnesota, etc... and most places recommend R-49 here now.

Assuming I need to basically add another 6-8" layer of R-25 or R-30 insulation, would I see localized benefits within her room by adding insulation only above her room? I do not have the money to add insulation to the entire attic at this time, and want to at least make her room more comfortable. The rest of the top floor is just fine as the doors don't need to be closed.

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Old 10-23-2008, 07:27 PM   #2
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Adding insulation to only a portion of an attic?


OK, I just got back from an adventure in the attic (easy to get up there, hard to get down w/o breaking the trim around the access hatch!).

Anyhow, the majority of the attic has approx. 11-13" of blown-in yellow fiberglass insulation.

HOWEVER, the rear-most portion of the attic (furthest from the access hatch), has areas with no more than 5" of insulation. This is the exact area above my daughters' room -- the coldest room!

Either the guys who blew in the insulation were too lazy to actually get 1/2 way across the attic to get it in that far corner, around the framing and stuff.

I guess I can probably get a buddy to help me out this weekend or next and get a few bails of the loose-fill insulation and at least top the low areas up to 12" deep, if not get that corner as high as possible using R-30 thickness (11"?) of this loose-fill stuff.

Or, should I look at renting the blower unit and really going nuts up there (specifically that corner) and topping up the insulation at least 5" everywhere (and 15" in that corner!)? The rental unit is $65/day, plus the cost of the insulation ($11/bushel of R-30, 25 sqft coverage when blown-in).

Any opinions guys?

Thanks a lot.
Eric

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Old 10-23-2008, 07:45 PM   #3
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Adding insulation to only a portion of an attic?


Just blew in some cellulose last weekend myself. I Purchased 11 bags to add an additional 5.4" of settled depth to the entire attice (24' x 24'). It was less than $70 US and the blower came free for 4 hours. The business is just a couple miles away and it took less than an hour to blow. Took longer to do the paperwork, loading, and returning the equipment than the actual job itself.

Should be a good return on your investment. I at least believe it will be for me.

Best of luck to you.
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Old 10-23-2008, 08:19 PM   #4
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Adding insulation to only a portion of an attic?


Wow only $70 for 11 bags and a free blower?

Home Depot here in Ottawa, ON, charges $10.xx for the bags and $65/day for the blower! My attic is roughly 24x40 = 960 sqft. That's about 24 bags to get a decent layer on there throughout.

Any idea what kind of savings I would see from upping the insulation from R35 to R50? ie: What percentage of heat loss is through the attic on a 2-storey townhouse? I could figure it out from there since I'd be giving myself 33% better insulation (or more considering the lack thereof in the one corner), on X% of my heat loss, at $Y/year to heat/cool the house.
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Old 10-23-2008, 08:57 PM   #5
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Adding insulation to only a portion of an attic?


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Wow only $70 for 11 bags and a free blower?
Yes, less than $6 a bag at our local Menards store (similar to Home Depot).


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Any idea what kind of savings I would see from upping the insulation from R35 to R50? ie: What percentage of heat loss is through the attic on a 2-storey townhouse?
This I would not know.

As for adding the extra cellulose, it was a suggestion from my auditor when I had our home energy audit done this past spring. It wasn't high on the priority list but as indicated, it didn't take me very long so I can check that one off my list.

What about grants? I recall another candian here recently expressing grant money for ecoGreen??
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Old 10-23-2008, 09:26 PM   #6
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Adding insulation to only a portion of an attic?


You are loosing more then you know in heat due to the loose fill fiberglass....and where it is 5 inches or so, you have hardly any resistance to heat loss. I don't know what you pay in utility bills to heat, but if you can spend $300 on cellulose and get a buddy to help, how long til it has paid for itself?
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Old 10-23-2008, 10:02 PM   #7
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Adding insulation to only a portion of an attic?


So is cellulose really THAT much better than fiberglass? I don't recall seeing it at the big orange store today -- just the pink panther fiberglass and then some blow-in fiberglass.

And regarding the rebates/grants, it costs $200 in inspection fees to qualify, and they only cover $200 (fed. and provincial combined), to go from anything higher than R-24, to R-49. So it's a wash and not worth it for me, unfortunately.
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Old 10-24-2008, 12:10 AM   #8
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Adding insulation to only a portion of an attic?


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So is cellulose really THAT much better than fiberglass? I don't recall seeing it at the big orange store today -- just the pink panther fiberglass and then some blow-in fiberglass.
Yes, cellulose is better and cheaper compared to blown fiberglass.
Cellulose | Fiberglass | Rock Wool
R-value/inch 3.23.8 | 2.22.7 | 3.03.3
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Old 10-24-2008, 12:17 AM   #9
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Adding insulation to only a portion of an attic?


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Yes, cellulose is better and cheaper compared to blown fiberglass.
Cellulose | Fiberglass | Rock Wool
R-value/inch 3.23.8 | 2.22.7 | 3.03.3
Cheap, easy to install, better R value,

Any down side to cellulose?
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Old 10-24-2008, 08:45 AM   #10
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Adding insulation to only a portion of an attic?


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Cheap, easy to install, better R value,

Any down side to cellulose?
I did some digging around online last night and found that adding cellulose over top of fiberglass isn't recommended, since cellulose is a fair bit heavier and will compress the fiberglass, reducing its R-value.

However, one site said that adding cellulose over top of fiberglass is good and will regenerate the R--value of the fiberglass under it when temps get really cold (fiberglass loses performance when its really cold - cellulose supposedly doesn't).

Anyone know what brands of cellulose insulation are commonly sold everywhere? I haven't seen it anywhere here.
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Old 10-24-2008, 08:49 AM   #11
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Adding insulation to only a portion of an attic?


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So is cellulose really THAT much better than fiberglass? I don't recall seeing it at the big orange store today -- just the pink panther fiberglass and then some blow-in fiberglass.

And regarding the rebates/grants, it costs $200 in inspection fees to qualify, and they only cover $200 (fed. and provincial combined), to go from anything higher than R-24, to R-49. So it's a wash and not worth it for me, unfortunately.
I just paid $315 for the first inspection. Of that $315, a $150 rebate is returned to me from the Gov.

Keep in mind that the Federal grant is matched by the Province of ON, effectively doubling it.

Increasing from a starting point of R-13 to R-25 to R-50 gets you $600, to R-40 gets you $400.
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Old 10-24-2008, 11:13 AM   #12
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Adding insulation to only a portion of an attic?


Thanks Reilly. Since I'm at R-30 or so right now (12" of loose-fill fiberglass), my grants wouldn't add up to much and wouldn't really offset the fees for the inspection.

I called around and Rona sells the bags of blown-in cellulose for $8.45/bag, rents the blower for $48/4hrs or $68/day. The total cost to upgrade my attic from R-30 to R-50 would be $285 before taxes (incl. the rental), and to go to R-58 would be $375 before taxes.

If blowing-in insulation really isn't difficult, then I think I will go for the R-58 total by adding 8" of blown-in cellulose to get a R-28 top-up (30+28=58).

So, is it easy enough to do?
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Old 10-24-2008, 11:14 AM   #13
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Adding insulation to only a portion of an attic?


Rock wool has the highest R rating of blow in insulation if I remember correctly.

More than likely what has happened is that the wind has blown the insulation away from your daughters room because of vents in the eaves.

I have seen this before and I just used a rake to push the insulation back over the rooms affected.
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Old 10-24-2008, 11:27 AM   #14
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Adding insulation to only a portion of an attic?


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Rock wool has the highest R rating of blow in insulation if I remember correctly.

More than likely what has happened is that the wind has blown the insulation away from your daughters room because of vents in the eaves.

I have seen this before and I just used a rake to push the insulation back over the rooms affected.
I thought about the wind possibly having done that, but if it did, the wind stole the insulation, because it isn't piled up anywhere in excess... it's just thin above that room -- applied in a hurry, whatever the case may be.
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Old 10-24-2008, 12:15 PM   #15
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Adding insulation to only a portion of an attic?


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I thought about the wind possibly having done that, but if it did, the wind stole the insulation, because it isn't piled up anywhere in excess... it's just thin above that room -- applied in a hurry, whatever the case may be.
From what I have seen it doesn't pile up some where else which confused me at first. It spread out pretty even over a large area. But after laying down some more insulation and having that happen again, the vent was the only logical explanation. Once I but in a baffle to divert the wind upwards the problem with the insulation went away.

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