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Attic insulation done improperly by previous owner.


m3rdpwr's Avatar
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MA

12-30-10, 09:05 AM   #1  
Attic insulation done improperly by previous owner.

I have a 1968 Ranch home.

When built, the insulation used was like a tin foil/paper insulation.
I hear the equiv of maybe R7.

So, the previous homeowner added insulation to bring it to the top of the 2x6 joists, great I thought.

So I wanted to add more insulation and to my horror they used faced batt's with the paper facing up!

So I guess I have a few ways to deal:
1) Ignore and add more insulation on top, not a good idea my guess.
2) Take out all insulation and flip upside down which could be a problem as well since it will still be a double faced insulation between layers.
3) Peel back the paper and toss before adding new insulation on top.
4) Remove improperly installed, toss, and buy twice as much, not really cost and green affective.
5) You tell me?

I would appreciate any good input.

Thanks!

-Mario

 
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marksr's Avatar
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12-30-10, 09:53 AM   #2  
I'd go with option #3, the original foil insulation should act as the vapor barrier...... but I'm just a painter and we have members that know a lot more than me about insulation - so stay tuned


retired painter/contractor avid DIYer

 
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12-30-10, 11:38 AM   #3  
Moisture travels through materials and the vapor barrier can prevent that. However, far more moisture travels along with air that leaks all over the place. In 68 they didn't pay a lot of attention to sealing holes for electrical, plumbing or gluing sheetrock to the studs. The result is a home where air can enter under walls through electrical boxes, can lights, and find its way into the attic. So, your number one item would be to air seal everywhere you can, link below will help. It opens slow but is good, efficiency Vermont.
http://www.efficiencyvermont.com/ste...ide_062507.pdf

Air sealing before you add more insulation will make the work a lot easier. As for which approach, I personally would go with #4, remove and start over. Multiple layers of old insulation will hide all sorts of dust, rodent droppings, and dead insects. Once everything is removed and cleaned up, you will find places to air seal you otherwise would have missed. Take pictures and save as a record to add to the overall value of your home and your investment will be returned. As for green, the better job will save more energy and offset any concerns about tossing the old insulation.

As for your choice of materials, blown-in cellulose is a popular choice. For batts, the stuff you see Mike Holmes using, mineral wool has some great properties. Review your ventilation and protect the flow of air. Upgrade if needed.

Bud

 
m3rdpwr's Avatar
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12-30-10, 01:50 PM   #4  
Great info guys, thanks.

One thing I should have added to #4 is even though I was thinking this, getting rid of 1,000 sq ft of insulation would be difficult.

I'd probably have to consider renting a small dumpster. lol

I have been working slowly sealing cracks, etc around outlets and the replacement windows the previous owner do not seal up. Foolish they could have did it very easily when they had the windows replaced and chose not to insulate those areas.

I also have to consider blown in insulation above the garage since the bedrooms are above they get very cold.

Well, I guess I'll have to look at dumpster options.

Thanks again...

-Mario

 
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12-30-10, 07:40 PM   #5  
One more question guys please.

So if I rip out everything, I would guess that I would install R19 first in the original 2x6 supports and than run 15" R38 the opposite way?
I would think that I wouldn't want the first layer to go above the 2x6 joists.

The 25ft rolls of R19 actually may work out well as the house is ~25 ft wide.
Although saying that may mean I would need something a little longer than 25 ft since the roof extends beyond the finished walls.
That being the case, maybe batts would be better.

Let me know what your thoughts are.

Thanks!

-Mario

 
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12-31-10, 05:44 AM   #6  
I've done both batts and rolls and although I thought rolls would be easier/better, I now feel batts are by far the best. You can fluff them to fit very well, end to end and sideways. Trying to fluff a 25 ft roll means adjusting it over the full length, a pain. Plus, if you ever have to go back into the ceiling below, no cutting or fussing, just pull a couple of batts and you are in.

One word of caution on using fiberglass batts is to protect the ends near the soffits so incoming air does not blow directly on the insulation.

And you are correct, r-19 in the cavity and whatever you want across the top.

Bud

 
GBR in WA's Avatar
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12-31-10, 09:38 AM   #7  
If you want the best job with fiberglass, use R-21 High Density, rather than R-19 (low density), and R-38HD rather than R-38 low density. The low density is prone to convective loops which will degrade your new R-value 35--50%; “How To” Buy/choose Fiberglass Insulation. - DIY Chatroom - DIY Home Improvement Forum

Gary

 
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