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-   -   Blown in insulation for un-insulated attic (http://www.diychatroom.com/f103/blown-insulation-un-insulated-attic-120526/)

Cubey 10-18-2011 08:26 PM

Blown in insulation for un-insulated attic
 
Okay, here's my situation. I bought my home in 2010 and it has NO insulation in over half of the attic. The house had a renter at one time that did various psychotic things such as hammer and chiseling out the cement porch outside the back door (which was actually part of the house's poured slab!) claiming it leaked in water under the door when it rained and tearing down a 70's built 16x16 pole barn so his kid could have a basketball court... so I wouldn't doubt he stole the insulation out of the attic.

Long story short, I need to do some serious insulating of my attic.

In a couple days, I plan to buy at least 20 packs of insulation from Lowes so I'll get a free blower machine rental. Already lined up someone to operate the machine while I work in the attic.

But I was wondering ... what do you do for a vapor barrier with blown-in insulation?

The original section of the house dates back to 1910, but it was completely renovated around 1997 and was tripled in size, so it has modern wiring, breakers and sheet rock throughout. The 1910 portion has plywood instead of sheet rock for the ceiling but that entire area, unless I am mistaken, has fiberglass insulation batts already installed. But I need to see if it has kraft paper or not on it. The vast majority of what needs to be insulated is the addition portion of the house, which has modern sheet rock ceilings.

Is a vapor barrier needed for blown in insulation if there is modern sheet rock ceilings and if so.. how do you do it? My only concern right now is blowing in insulation to the portion of the attic that currently has no insulation at all. But I want to be sure I do it right and provide a vapor barrier if one is needed. I am located in Southern Arkansas, in case that makes a difference in whether I need it or not.

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EDIT: I came across a page that says to do this:

http://www.bpa.gov/energy/n/energy_t...figure3.11.gif

Good lord that would be time consuming! Cutting the plastic into strips like that, stapling it all in? Geeze... it would take me days to do that I bet! But if it's needed I guess I will have to do it. May have to put off doing this until next week if I have to install strips of vapor barrier first!

gregzoll 10-19-2011 12:30 AM

It would be easier and cheaper to hire someone that knows how to do this. You only need to make sure that gaps are sealed between the living space and the attic space, before they blow in insulation. That means going up there with caulk and spray foam. If you have can lights that penetrate the space, they make a xps & pressed roxwool cover for them, that you seal with caulk.

And as for vapor barrier, you do not put it up after the fact, when homes are built, before gypsum is put in place, and Tyvek is not going to be used, you place visqueen over the ceiling & wall space as to make a continuous barrier, and seal any penetrations like light switch boxes & receptacle boxes. The better you can make the home airtight, the more you have to allow for make up air from the outside, so that you do not make the home "sick".

Cubey 10-19-2011 12:41 AM

Thanks for the reply.

I don't have any can lights nor do I want any. *LOL* Not my taste.

I think I will just bite the bullet and go with faced R30 insulation batts instead. I will just have to slowly buy them since they cost so much more than blown-in does. Maybe I can afford to get one package (88 sq ft) per every 1 or 2 months until I have the empty areas filled up. The rest of the attic has maybe R13 or R19 I'd guess, so then I will proceed to add un-faced batts or rolls on top of the existing faced insulation. It's going to take forever but it beats doing nothing at all or running up a ton on a credit card and losing the savings due to interest payments.

gregzoll 10-19-2011 12:51 AM

Batts are a waste of money for attics. You would need minimum R-39, or as much as R-60, depending on where you live. You can get better insulating quality with blown in, and it is a lot cheaper.

Cubey 10-19-2011 01:02 AM

Right now half if not two thirds of my attic has R-0... no insulation! So R30 beats what it has now. I'm also thinking about how the pipes are in the attic... supposing I have a leak, I can only imagine the horror I'd have of trying to clean out heavy, wet, blown-in insulation. At least with batts, I can bring up a trash bag, put it inside of it and lug it to an attic access hole and drop it down as one piece... not millions of tiny shreds of wet insulation.

And don't think a leak couldn't happen... the guy did a pretty poor job. I already found and fixed a leak in the attic from his poor work. I fixed it twice actually. The first time, I used PVC cement that was too old and it didn't seal properly. :/ Second time (with new pieces of pipe of course) was the charm... no longer leaking. The fiberglass insulation bat under it was able to dry out and be re-used and it wasn't a horror story to lift it up and get it off the sheet rock, since fiberglass doesn't absorb as easily and can be moved faster and easier.

By the time I bother paying someone to do a professional job with blown-in, I may as well buy the batts and do it myself and have the advantage of batts instead of blown-in in case of a leak. Remember: ALL my fresh water pipes run through the attic.

Once I get the first layer of faced batts installed, I can use any size width unfaced batts or rolls on top of the existing insulation to add to it. I am on a tight budget and need to do SOMETHING to add some insulation to it without painting myself into a corner with blown-in.

gregzoll 10-19-2011 01:33 AM

There should be no water pipes in the attic space. If there is, you deal with it, if something does happen. Still, with R-30 batts, you are wasting money. Minimum should be 6 inches of blown in, 10 to 14 is better.

Cubey 10-19-2011 10:16 AM

Another factor is my attic doesn't have a lot of headroom. I am wondering how well I'd be able to install blown-in with so little headroom. Last year I went in and put in pipe insulation and that was tough enough. Having to stay upright and aim a hose in a tight place would be awfully hard.

And as you said, for such a job, a pro would be better. Supposing I do go with blown-in and I don't do a good job, I may as well have gone with batts since that can be adjusted at least after the fact.

I don't like "wasting money" which is why I think in my situation, I may be better off with fiberglass over blown-in since I am wanting to do the job myself and I have PVC/CPVC water pipes in the attic to consider. Yes, it's going to cost a lot more and give less R-value but it's more of a guarantee that it's done properly and doesn't require skill to install. I will just add to it as I can.

gregzoll 10-19-2011 10:31 AM

You get a couple of skinny high school or college kids.

Cubey 10-19-2011 11:25 AM

Something else has crossed my mind. The pipes are almost all to the side of the house, leaving about 3/4 of the space being away from the pipes. Maybe I should do blown-in insulation in the 3/4 area that is away from the pipes and do batts in the other 1/4 so I can have the best of both worlds. If I have a minor leak, it will be limited to area where the batts are. But for the most part, I will have much cheaper blown-in insulation.

I am going to go pick up some tubes of caulking and a can or two of spray foam and start working on sealing around light fixture boxes and such. While I'm up there doing that, I will evaluate the attic a bit better and see how i want to do it for sure before I commit to buying any insulation. Thing is, some of my rooms are rather large. I wonder if the sheet rock is put up well enough to support the weight of blown-in, that's another thought that crossed my mind.

gregzoll 10-19-2011 01:03 PM

Blown weighs no more than batt.

Cubey 10-19-2011 08:08 PM

Well I decided on what I am going to do. Since the attic already has R-19 batts installed, I bought 4 packs of faced R-19 batts to install for now. Later on when I can afford it, I will install unfaced R-30 rolls ($10/each for 16" x 25') on top of the R-19.

Basically, I am needing a band aid for the lack of insulation ASAP. Yes I know, R-19 is not enough but it's going to be a huge improvement over what's NOT up there now. Reason why I went with R-19 to start with is it'll give more sq ft coverage (133 sq ft per pkg) for the same price as faced 23" wide R-30 (88sq ft per pkg). So instead of installing 352sq ft of R-30, I will be installing 532 sq ft of R-19. And again, that's just the start. 532sq ft will or will almost completely fill up the area without any insulation. I might have to go get one more package so at least the entire house will have R-19 without any bare spots, if these 4 don't do it. Any leftover batts can go in my well house or garage attic.

I also got 2 tubes of caulking and 2 cans of foam spray so I can do some sealing work before I start on installation of the insulation.


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