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Posted: 1/25/2014 1:12:05 PM EDT
I think my attic is severely under insulated but I'm not entirely sure what type on insulation I have.I am trying to figure out the R value of my current insulation so i can decide how much insulation would need to be added.There is about four inches of this insulation in my attic. it appears to be blown in. I am planning on doing a diy blown in insulation. any recommendations on type or any tips or trick i should know about before i try to this?

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Link Posted: 1/25/2014 1:33:21 PM EDT
It looks like blown fiberglass. You can look up an R value chart, but you are only around 14-15 at four inches. Definitely not enough for Ohio. Blown cellulose is an easy DIY, just make sure that you don't block any soffit vents.
Link Posted: 1/25/2014 1:44:14 PM EDT
I just replaced the 52 year old insulation in our attic, so I have some sympathy for what you are about to get into!  




I had found this website during my research that tells how to calculate R value to a degree, maybe it will help you:





















Unless I misunderstood the stuff I read online at a .gov site and several home improvement sites, it seems like more is better as far as the thickness of the insulation.  Something along the lines of 'doubling the thickness of the insulation doubles the insulation value'.



















I'd advise on going online to a couple of self help sites to get tips on adding insulation.  Little stuff, like keeping insulation away from your soffit vents and certain types of lighting fixtures, is stuff that you gotta know about before tackling a job like this.  The best thing I did was buy a couple of tyvek suits and face masks.  That was well worth the cost.



















I was initially going to use the blown in, non fiberglass insulation, but ended up going with unfaced fiberglass stuff in rolls, because I could double my R value for about 2/3rd of the cost.






The new fiberglass insulation feels different than stuff I have been around in the past.  It didn't seem nearly as itchy.







The unfaced stuff in rolls would be really easy to install if you are installing them over top of existing insulation in a fairly open area.  My attic was fairly tight, so I had to do a fair amount of manhandling of the rolls (they tended to want to unroll on their own).













If I can find the other websites I used, I'll edit this post with them.  

 
 

 
 
 
Link Posted: 1/25/2014 3:07:48 PM EDT
Before you add insulation, air-seal your attic.  Move the insulation out of the way.  Run a bead of expanding foam over the top plat of each wall on the interior of your home.  Build a rigid styrofoam box around things like bath exhaust fans.  Build a rigid styrofoam box around recessed lighting.  Seal around electrical box, pipe, tube, and vent penetractions.

Around the perimeter of your attic, inspect the eves.  Seall the top plate on the exterior wall and ensure your attic venting is correctly set up.  You probably have soffet vents.  Make sure then are not obstructed, but they should vent from the outside only, NOT from the walls, etc.

Then, get bags of cellulose insulation.  If you buy 10 or more bags from HD or Lowe's, you can rent the blower for free.  this is a two person job, one to feed the machine with bags, one to crawl around up above and blow.  Go for even, complete coverage.  12" is a good starting point.

Sealing first, though.  If you don't stop the drafting, all the insulation in the world is just an air filter.

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Link Posted: 1/26/2014 2:35:18 AM EDT
[Last Edit: 1/26/2014 2:35:40 AM EDT by ColtRifle]
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Originally Posted By DieselEngineer:
Before you add insulation, air-seal your attic.  Move the insulation out of the way.  Run a bead of expanding foam over the top plat of each wall on the interior of your home.  Build a rigid styrofoam box around things like bath exhaust fans.  Build a rigid styrofoam box around recessed lighting.  Seal around electrical box, pipe, tube, and vent penetractions.

Around the perimeter of your attic, inspect the eves.  Seall the top plate on the exterior wall and ensure your attic venting is correctly set up.  You probably have soffet vents.  Make sure then are not obstructed, but they should vent from the outside only, NOT from the walls, etc.

Then, get bags of cellulose insulation.  If you buy 10 or more bags from HD or Lowe's, you can rent the blower for free.  this is a two person job, one to feed the machine with bags, one to crawl around up above and blow.  Go for even, complete coverage.  12" is a good starting point.

Sealing first, though.  If you don't stop the drafting, all the insulation in the world is just an air filter.

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This.  Good advise here.

OP....your insulation is fiberglass.
Link Posted: 1/26/2014 7:40:25 AM EDT
I added insulation to a single story home about 5 years ago. It had none in the attic area. I went with the blown in insulation for ease. You had one person up in the attic blowing with was basically a 4' diameter flexible hose that had a start and stop key fob attached so the person in the attic could control it. Then you had a second person feeding the machine to ensure a constant flow of insulation. One thing that i did was go into the attic prior and measure and mark the joists / stringers to ensure a R49 depth. I only found after they make a paper ruler you can actually get for free and staple up there that gives you the depth and R value. The material that you have I would leave up there and simply blow the new material over the top of it. I went with the R49 based on the info provided by web page for my area. After it did my bill almost $70 a month less on even billing for the house. So it was well worth it. Just make sure you pick a nice day out, its amazing how hot even on a cool fall or spring day how hot it can become in an attic.
Link Posted: 1/26/2014 8:14:53 AM EDT
Build a rigid styrofoam box around things like bath exhaust fans. Build a rigid styrofoam box around recessed lighting.


Make sure you leave room inside those boxes for heat/etc, especially if those devices are NOT IC rated
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