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-   -   Blown in Fiberglass (http://www.houserepairtalk.com/f106/blown-fiberglass-10570/)

jdkd 12-27-2010 11:54 AM

Blown in Fiberglass
 
Hello, I just found this site, and have a question that has been bothering me. I have a older home that was built in the late 40s or early 50s, not sure of the date. In my attic I noticed that the insulation was below the rafters, what was there was cellulose. I had a company come in a blow fiberglass in the attic over what was there. I cant remember the exact r value they added, but I think it was r42 it is very deep now. What my question is, I was under the impression that when it snows that if a home does not have good insulation that the snow leave the roof very fast? Well it has snowed 2 times now, and the snow is gone as fast now as it was leaving before we added the new insulation. Do I have some kind of problem, or could this be ok? I hate to think that all the new insulation was not a help? Thanks for any answers you may give!

paul52446m 12-27-2010 01:29 PM

Quote:

Originally Posted by jdkd (Post 52464)
Hello, I just found this site, and have a question that has been bothering me. I have a older home that was built in the late 40s or early 50s, not sure of the date. In my attic I noticed that the insulation was below the rafters, what was there was cellulose. I had a company come in a blow fiberglass in the attic over what was there. I cant remember the exact r value they added, but I think it was r42 it is very deep now. What my question is, I was under the impression that when it snows that if a home does not have good insulation that the snow leave the roof very fast? Well it has snowed 2 times now, and the snow is gone as fast now as it was leaving before we added the new insulation. Do I have some kind of problem, or could this be ok? I hate to think that all the new insulation was not a help? Thanks for any answers you may give!

Ceiling insulation has to breath so heat will still go through it, but much slower with more R value. The very big question here is, how well is your attic ventilated, Is your over hangs vented and open all the way to the attic? Do you have ridge cap vents and gable end vents. You can't over ventilate a attic. I hope you did not have insulation blow en and they did not ventilate properly. Later Paul

jdkd 12-27-2010 02:47 PM

I have large gabel end vents, and 2 smaller vents in my attic. They did not add any venting, just what was already there.

paul52446m 12-27-2010 05:16 PM

Quote:

Originally Posted by jdkd (Post 52470)
I have large gabel end vents, and 2 smaller vents in my attic. They did not add any venting, just what was already there.

A attic ventilates by warmer air going out the hi points like ridge cap and hi gable end vents. For the warm air to go out fast enough, there should be continuous venting around your hang over, all the way around the house.
You also need to make sure the that insulation is not touching the roof, out by
the hang over. They should have put proper vents to hold the insulation down from the roof and to make good air flow. Later Paul

jdkd 12-28-2010 08:24 AM

The insulation does not touch the roof. My furnace and AC unit is in my attic, so I do have room up there to walk around, it looks like a very good bed of insulation, I just dont understand why the snow does not stay on the roof longer?

oldognewtrick 12-28-2010 02:07 PM

Quote:

Originally Posted by jdkd (Post 52481)
The insulation does not touch the roof. My furnace and AC unit is in my attic, so I do have room up there to walk around, it looks like a very good bed of insulation, I just dont understand why the snow does not stay on the roof longer?

Have you checked all the ducts to see if you are heating the attic by a loose fitting duct run?

paul52446m 12-28-2010 04:09 PM

Quote:

Originally Posted by jdkd (Post 52481)
The insulation does not touch the roof. My furnace and AC unit is in my attic, so I do have room up there to walk around, it looks like a very good bed of insulation, I just dont understand why the snow does not stay on the roof longer?

Even if you duct work is sealed and covered with insulation, Your furnace
is putting off a lot of radiant heat. Any time i put a furnace in a attic, i warn
people about the heat in the attic melting snow and making ice on the hang over. You can put a powered venter in a gable end. But you have to be very careful not to pull a vacuum on the attic space. Do you have a 90 plus furnace
with two stacks for sealed combustion? or is your furnace a 80 plus with a
galvanized metal stack? later paul

jdkd 12-28-2010 07:21 PM

I have a 80 plus furnace, the furnace man told me he didnt advise a 90 plus do to the fact it was in my attic, something about condensation I think. The metal stack goes directly into my brick chimney, and out the roof.


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