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Old 09-20-2008, 09:45 PM   #1
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Attic Insulation - Current R Value?


I am trying to determine if I need to add more insulation to the attic. The Joists are 6.5" deep. I now highly suspect I do, now that I see it is only about 6.5" deep.

I am not sure how much insulation you would say I have right now, since some of it is above the joists, yet, as you will see in the photos, many area are not much thicker than the 6.5 inches.

I am in Wisconsin.

How would I determine what approximate R value I currently have in the attic?



They are filled up with insulation, and some fluf on top of it, some areas have more than others.

The plank in this photo sits right on top of the joists, so that gives you some perspective, there is only 6.5" of room between the celing and the bottom of that plank:



One more photo, you can notice the joists being visible much of the way back in this photo.




Thanks again everyone for all the recent help. It has been so crazy with all the projects I am trying to get done before winter. It is amazing once you get working on some projects how you quickly find many more projects that need to get done because the first project is either dependent on them being done or you have discovered problems you were not aware of.


Jamie

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Old 09-23-2008, 01:29 AM   #2
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Attic Insulation - Current R Value?


At best looks like r19 to me but you can measure it directly by multiplying the uncompressed depth of a batt by 3.2. I say "at best" cause with every gap or tear you see there in the insulation you have a significant lowering of the R value and greater heat loss. In your part of the country you should definitely have R49. I would lift up the batts to see if any additional airsealing needed to be done like chimmney chases , plumbing chases, tops of interior walls or gable walls which alot of times have no top plate and are open to the attic. You will probably find some bad gaps that will be easy to get to now. Use foamboard and sprayfoam there and when needed fireproof ductboard/foam for the chase (didnt see a chase though) then relay all the batts that are kinked to make it uniform and then blow in some cellulose insulation over the top of it all at the right depth to get your R49. Just dont cover any soffit vents if you have them and make a dam around any heat source.

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Old 09-23-2008, 02:37 AM   #3
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Attic Insulation - Current R Value?


A couple of quick Google searches for you.


From and energy company the R-value of Insulation is 3.25 per inch and from the University of Wisconsin you should have an R-value of you should have a R-value insulation of 38 which is about 12 inches.


So according to the University of Wisconsin you need about twice the amount of insulation that you have.


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Old 09-23-2008, 02:39 PM   #4
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Attic Insulation - Current R Value?


Thank you both for the information. I am going to plan on doubling the insulation up there. I don't have any vents to worry about covering. The only vents up there are near the ridge and are a good 4 feet from the floor. There are not a lot of wires up there, only a few for lights, and most of the wires for those sneak down into a lower attic that is insulated. The celing is framed tight to the chimney and the insulation sits all around it. I'll double check again, but I don't think there is much at all in the way of openings that come down into heated space.

I will straighten out the wadded up pieces of insulation. Is there any kind of blow in that is best, do I just want the regular fiberglass blow in insulation?

Thanks again
Jamie
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Old 09-23-2008, 03:24 PM   #5
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Attic Insulation - Current R Value?


Cellulose is the best option for you since its easier and cheaper, gives better coverage/airsealing, and performs better at very low temps compared to blown fiberglass i think.
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Old 09-23-2008, 08:50 PM   #6
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Attic Insulation - Current R Value?


Had a home energy audit performed earlier this year and the auditor said that the white fluffy "make you feel good" fiberglass that was blown into our attic
is very inefficient. He advised me to put 4-6 inches of cellulose over the top.
Here are some links for you:
http://www.ornl.gov/sci/roofs+walls/...on/ins_16.html
http://apps1.eere.energy.gov/consume.../mytopic=11340

Best of luck.
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Old 09-24-2008, 12:58 AM   #7
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Attic Insulation - Current R Value?


Quote:
Originally Posted by Winchester View Post
Had a home energy audit performed earlier this year and the auditor said that the white fluffy "make you feel good" fiberglass that was blown into our attic
is very inefficient. He advised me to put 4-6 inches of cellulose over the top.
Here are some links for you:
http://www.ornl.gov/sci/roofs+walls/...on/ins_16.html
http://apps1.eere.energy.gov/consume.../mytopic=11340

Best of luck.
Thank you both again for the helpful information. I will price out the cellulose tomorrow and see if I can get the project done right away!

Thanks
Jamie
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Old 09-24-2008, 12:09 PM   #8
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Attic Insulation - Current R Value?


Quote:
Originally Posted by jamiedolan View Post
It is amazing once you get working on some projects how you quickly find many more projects that need to get done because the first project is either dependent on them being done or you have discovered problems you were not aware of.

Have to agree with this very true statement and suggest that before you add additional insulation check to be sure that your venting situation really is adequate. You said you don't have soffit vents but maybe you should and it's easier to add them before the extra insulation.

I didn't quite understand whether you just had a ridge vent or whether you also had additional vents lower in the attic.
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Old 09-24-2008, 01:42 PM   #9
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Attic Insulation - Current R Value?


There is a very easy way to blow in the extra cellulose insulation into your attic. You do have to remember the settling amount that is listed on the bags. It does settle a fair amount, so you have to know the depth to shoot it at.


I needed to add insulation and found out that Home Depot is nice enough to let you use one of their machines that make it a very easy job for free.


It is a 2 person job. You need someone down below filling the large plastic hopper with the cellulose. Home Depot gives you plenty of hose to do about any attic. You flip on the blower and it shoots out the end of the end of the hose with a very good power/range that makes getting the insulation back into the corners easy. As long as the hopper is kept filled the fairly good and even flow of the insulation combined with the good range makes it a quick and easy job.


You get to stay in the highest part of your attic and just back your way to the entrance to your attic spraying as you go and just run the machine empty before you get out of the attic.


It does get in the air, so a set of goggles and an air mask are a pretty much of a must have. The nice thing is that it isn't fiberglass so you won't itch when your done.


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Old 09-24-2008, 03:29 PM   #10
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Attic Insulation - Current R Value?


Quote:
Originally Posted by jogr View Post
Have to agree with this very true statement and suggest that before you add additional insulation check to be sure that your venting situation really is adequate. You said you don't have soffit vents but maybe you should and it's easier to add them before the extra insulation.

I didn't quite understand whether you just had a ridge vent or whether you also had additional vents lower in the attic.
A picture is worth a thousand words. The attic in question starts about 1 foot above the window shown in this photo. This is the vent on the south end of the house:





Larger view of same area:



Vent at opposite end of that attic:





Vent at the end of the far side of the house, This is connected to the same attic, this end of the attic is just much shorter / lower than the main attic.



Thanks

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Old 09-24-2008, 06:04 PM   #11
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Attic Insulation - Current R Value?


The house had a couple of those old (this is a tough one) galvanized metal that curves down to keep the rain out type vents. A pretty much useless venting system, but the house was built when it was a lot cheaper to heat and cool your house.


Ridge vents work great and is something that is becoming standard on home sin Florida. It's a very easy DYI project to add them on. All you need to do is:

  1. Measure the length of all of the ridges on your roof, then subtract about 4 feet for every end. They look kind of strange if you don't start them about 4 feet from the end of the roof.
  2. Drag out your trusty Circular saw and set the depth for the ridge shingles and the plywood underneath. You don't need to be exact, if you cut a little way into the truss it won't hurt anything.
  3. Cut down both sides of the ridge of the roof about 2 inches from the top. I'm pretty sure that the vents are 6 inches, so you put a mark on the front end of your circular saw and just free hand the cuts. You want to stop the cuts about 7 feet from the end of the roof to prevent any chance of rain water working it's way back to the cut. There's a plastic cap for the end, but that is pretty much just to stop critters from making a home in your ridge vent. (The one thing you don't want is to have bats make a home in your attic and they can get in some pretty small openings. If someone you know ever gets them there is an easy way to get rid of them. Find out where they are getting into the attic, wait at sunset until they've all gone hunting for the night, then stuff steel wool into the opening. When they come home from hunting they find their hole stuffed with steel wool, that they cant chew throw and head elsewhere.)
  4. You put the ridge vent on with screws that have rubber grommets on them, so there's no messy tar or anything like that. I over kill and over lay each section by 2 feet, but I'm in southern Florida. (We get a lot of what we call “Full Blown Florida Frog Choker” rain storms. Growing up in Illinois when you got a storm like these you started looking for the tornadoes. We went to a concert at the stadium where the Tampa Rays play (they just took the devil part out of their name) that was at first correctly named the Thunder Dome. We got lucky and had to pick our tickets up at the “Will Call” window that had the only indent in the building right next to it. A Frog Chocker hit and we were tucked in that one indent watching a manhole cover blow mist out the 2 lift openings and then when the pressure got to high the man hole cover would literally pop open, spin like a titily wink and drop back into it's hole. The people getting dropped off by buses from the out parking didn't even bother to run because they were soaking wet after the first 3 feet. I bet they made a fortune on the overpriced concert T-shirts. The lighting guy for the band stepped out and looked at what was probably his first Frog Choker and asked if he should shut his system down. I just looked at him and said, “Why do you think the named this the Thunder Dome?” He just let out a “Jesus!” and shot back inside like a bullet.)

Depending on wear you live, you can probably use their suggested overlay, which you have to
remember to add into the total length of ridge venting you need.


Just looking at the fairly small opening you've made in your roof and then covered with the ridge vent (I should point out that the ridge vent has air holes every 3 inches down both sides) might not be making the major difference that it does. But id you add it up 60 feet of ridge vent is more than ripping a huge hole in your roof. It's more because it's all ant the peak and that kicks in “hot air rises”. If you have good venting in your sofits it makes the cooler air from the shady area under your sofits flow up your attic and out the ridge vents at a pretty good rate.


The popularity of the ridge venting system is bringing back the old ceiling fans. The fairly big
and high volume fans that you mount into the ceiling inside the house. They don't make the noise like the old one's that occasionally see anymore. You still want to put them in an area where the noise of the wind and fan won't bother you. These fans can pump a lot of air, that has a place to go to now. You open the windows and you can feel the breeze of outside air coming into the house.


I've cut my power bill down quite a bit using one. When I leave in the morning I put the A/C all the way up to 85 or even shut it off depending on how hot its going to get (I'd always shut it off it I didn't want to come home and find my dog had died. The dog sleeps all day anyway so 85 isn't torturing the dog). When I get home I turn that fan on and open up a few key windows and let the fan run for 10 to 15 minutes. It cools down quick, but you want to let it suck the heat thats soaked into the couches and beds out of the house. Then I shut the fan off and turn the A/C on.


You'd be surprised at the number of days that you would normally have the A/C running that you can run the ceiling fan instead. Even if it's cool enough outside unless you have a pretty good breeze going it won't keep your house comfortable, but the fan replaces the breeze and costs a lot less to run than the A/C. It also has that extra benefit of keeping the inside of your house “aired out.”
  1. They only have aluminum louvers that close when you shut the fan off, so in “Yankee Land” you want to have a chunk of insulation to put over the fan opening during winter.


    BJ
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Old 10-23-2008, 12:24 PM   #12
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Attic Insulation - Current R Value?


Well, any progress here? I am over in Madison, and have the exact same scenario as you. How much did it cost you if you did it yet?

Thanks! - Evan
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Old 10-23-2008, 12:33 PM   #13
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Quote:
Originally Posted by 240sx4u View Post
Well, any progress here? I am over in Madison, and have the exact same scenario as you. How much did it cost you if you did it yet?

Thanks! - Evan
Evan;

I am in neenah. I have insulated one of my attics so it is about R40 now, it feels much warmer downstairs in the rooms under that area. I have not delt with the main attic yet. I want to add in some of the vents as people have suggested here and that is not something I really am going to be able to deal with this year. So I doubt I am going to add anything to the main upper attic this year. I may increase the floor insulation in the second lower attic to about R40 as well, it is about R19 now. It is a large space and is about 700 feet of R19 and I either have to lift up floors in the storage area to get the new insulation in or remove the old batt insulation and blow in new insulation into the whole area. In the small attic, there was only 4 feet of flooring, so I was able to lay down and reach under with my arm to get the batt insulation in place.
I plan to blow insulation into the large upper attic.
'
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Old 10-23-2008, 12:40 PM   #14
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Attic Insulation - Current R Value?


Thanks Jamie, sounds like fun! I was curious as to perceived warmth. I have been mulling this over since the inspection when I bought the house and am dreading high heat bills. Honestly, the bills suck but a drafty cold house is much worse to me. I am going to really try pulling together some money for the insulation before it gets too nasty outside. I am glad you made some progress, its supposed to be a cold winter this year!

After reading alot on this forum, it seems like you can blow in insulation over the flooring in the attic with good results (of course this is assuming your not using it for storage!!


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Old 10-23-2008, 12:41 PM   #15
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I feel like an idiot, just found your other thread! Ill run over and read it.

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