# Is my attic insulation adequate?



## Mike68847 (Jun 29, 2011)

Our house is in central Nebraska. Utility bills aren't outrageous, but I wonder if I can do better. The house is about 12 years old and we're ther second owners. In the picture below, the insulation is about 6-8" deep. Any comments or recommendations?

Mike
central NE


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## joecaption (Nov 30, 2011)

Not enough. http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table

Need to check to see if anyone air sealed before adding the insulation that's there.
Sealing up anyplace plumbing, wiring lighting was run into the attic with spray foam will be a big help.
If someone added can lights make sure there IC and air tight fixtures. If not your going to have to add some covers.


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## Mike68847 (Jun 29, 2011)

Thanks for the info. Any advantages to blown ("fluffy") vs. rolls of insulation?


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## joecaption (Nov 30, 2011)

Blown in is better and less expensive.
Lowes and Home Depot will let you use there blower if you buy 10 bags for free.


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## Mike68847 (Jun 29, 2011)

Great! I didn't know that.:thumbup:


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## joecaption (Nov 30, 2011)

Going to need two people, make sure to pick up some dust mask. One down stairs loading the other in the attic blowing.
I find it works best to have the blower sitting on a 12 X 12 tarp to reduce the clean up time. It's messy stuff to try and just rake up.
Do not cover up the area that extends out over the walls with out adding foam baffles first.
You need air flow from the soffits to the roof vents.
http://www.bing.com/images/search?q...8ADFF55D933D9EA82501A5E2CC3E&selectedIndex=39
I've found it easier for me if I duct taped a piece of 3" PVC pipe to the flex hose on the blower. That way I can stay in the middle and hit the sides without having to even bend over.


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## Mike68847 (Jun 29, 2011)

Thanks again. More stuff I didn't know.


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## Fix'n it (Mar 12, 2012)

joecaption said:


> Lowes and Home Depot will let you use there blower if you buy 10 bags for free.


round here, its 20 bags at HD. idk about lowes. and menards charges no matter what.


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## Mike68847 (Jun 29, 2011)

Thanks, Good to know this in advance.


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## MikoMcGreg (Feb 11, 2014)

When installed properly, loose-fill insulation improves the energy efficiency of a home, lowers utility bills and decreases carbon dioxide emissions...


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## Windows on Wash (Aug 30, 2011)

+1

Add some more and you are good.

Air sealing is great too if you can at least get the big stuff.


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## digitalplumber (Jul 8, 2011)

Why is blown in better? Batts are batts and cannot manipulated based on installation. Blown in can by the installer, so although you have 20 inches, if there is too much air it will settle, correct?

If you need access, batts are easier too move and work, except in the case were blown in is your bottom layer.


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## Windows on Wash (Aug 30, 2011)

Blown in is easier to install, easier to get more uniform coverage, tends to settle into crevices more effectively and self level, etc.

Fiberglass doesn't settle and cellulose does a bit but its overall R-Value doesn't really change as a result. 

You shouldn't need to be in the attic that much and I would plan on getting everything done that you want to first, then insulate.


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## digitalplumber (Jul 8, 2011)

One thing that is always overlooked and the easiest to insulate and closes a huge hole, is the attic staircase. I read a report a while back that you can do all of the attic insulating correctly, but if you do nothing to the attic stairs you have left a huge void that impacts by reducing your insulations benefits by 30 percent I believe.


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## Jb1234 (Aug 18, 2012)

Your attic looks almost exactly as mine. My plan was to do the blown in this spring. Great tip Joe about adding the PVC pipe to the front.


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## Windows on Wash (Aug 30, 2011)

You do need an airtight enclosure around the attic stairs. They sell them or you can make your own.


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## Gary in WA (Mar 11, 2009)

Mike, you really can't compare them. IMO, batts are for limited headroom, cathedral ceilings, or over a bath fan for future replacement. The batts are fine for low slope (restricted headroom and lower insulation dams around scuttle hole access), around recessed lighting without building a cover or with standard joist spacing, but blow-in is easier with multiple obstructions. IMO, need an elevated walkway for any HVAC - OR (removable) batts just from the attic scuttle to unit for filter changes. Just raking blow-in aside for access and replacing leaves big air pockets (de-rating the R-value) because the insulation clumps up with further movement. 

The FG batts are available in much higher densities than the blow-in for perimeter application where roof slope interferes with full R-value. You don't want the insulation touching roof sheathing or even framing (R-1.25 in wood-- thermal bridge)- premium to use stacked/sloped (baffles of XPS) rigid foam board over the exterior walls (1' wide) for maximum insulation in that restricted height- no conduction loss. Use of blown-in FG = R-10 at that 4" height and this is the coldest wall in the house (due to exterior location and air vents directly coupled above).http://bct.eco.umass.edu/publications/by-title/reroofing-and-residing-to-save-energy/

There are recirculating convective loops in all gabled attics that are vented- the cold incoming air sinks to/through the top inches of blown-in quite easily due to the low density- mixing with the heat flux rising from room below; http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1059&context=mechengfacpub&sei-redir=1&referer=http%3A%2F%2Fwww.google.com%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3Dv

The more insulation you add, the better it is as the density increases from the weight above = better product. Still, even at R-60, the density is only 0.58#ft.cubed;http://www.r-prollc.com/Documents/Atticat_Insulation_Fact_Sheet.pdf 


Your local code requires R-38; http://energycode.pnl.gov/EnergyCodeReqs/index.jsp?state=Nebraska --------------- Six-sided air barrier required for full R-value; https://docs.google.com/viewer?a=v&...whJgNT&sig=AHIEtbT0wgPl1yn5T5V8M8l_EeA2F-qvvA

So, to counter the convective loops and the attic wind-washing, IMO add a housewrap over the top- like Tyvek as it will also work as a radiant barrier of sorts;http://www.homeenergy.org/show/article/year/1992/id/895

Or from above, at new construction; http://www.philwrites.com/AW_Manual_12_1_all_LR.pdf

Gary
PS. OR just fill it to R-60...lol.


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## Jb1234 (Aug 18, 2012)

Gary in WA said:


> There are recirculating convective loops in all gabled attics that are vented- the cold incoming air sinks to/through the top inches of blown-in quite easily due to the low density- mixing with the heat flux rising from room below; http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1059&context=mechengfacpub&sei-redir=1&referer=http%3A%2F%2Fwww.google.com%2Furl%3Fsa%3Dt%26rct%3Dj%26q%3Dv


I believe my brain just imploded trying to fully understand this.


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## Mike68847 (Jun 29, 2011)

Thanks everyone for all your comm,wents and suggestions. I'm learning a lot.


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## Gary in WA (Mar 11, 2009)

Yes, I've used that link to show convective loops are always in an attic (with passive venting), cold------ ; or *hot climate*; http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-226-91/

Now I'm trying to convert the heat flux (using same outside temps) through the attic insulation (R-20) compared to heat through a 2x4 (R-13) exterior wall-- *pp.86:* http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CFMQFjAH&url=http%3A%2F%2Fwww.diva-portal.org%2Fsmash%2Fget%2Fdiva2%3A506266%2FFULLTEXT01&ei=l-5-UtznJoKKiALH_oGQAQ&usg=AFQjCNGxnp4-9hrPSTKbC5n6vQVAkslv7g&bvm=bv.56146854,d.cGE&cad=rja But the wall outside temp is 5*F, with *10* W/m2 loss and the ceiling (R-20) with 32*F outside and *37 *W/m2 loss, and 21*F out with *48 *W/m2 loss; almost 5 times more loss and temps are warmer in attic (w. 4cm vents) than wall exterior..... anybody?

Send me a PM if you want, I'd love some help on this. Thanks, Gary

PS. the colder air (less dense) settles on the attic floor being warmed by the heat loss through the insulation to rise/exit the high vents; http://learn-science.20m.com/tmyths.htm#myth2

http://www.usatoday.com/tech/columnist/aprilholladay/2005-02-18-wonderquest_x.htm


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## Queef (Jan 26, 2014)

If you know of any painters, an extendable and retractable painters pole is handier than a pocket on a shirt for blowing in insulation. Duct taped to the blower hose and you're GTG.


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## Nailbags (Feb 1, 2012)

going from R-19 to R-49 is not that costly. Once you have blown in that is what you need to stick with. you can have batts then cover with blown in but not the other way around.


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## Nailbags (Feb 1, 2012)

Gary in WA said:


> Yes, I've used that link to show convective loops are always in an attic (with passive venting), cold------ ; or *hot climate*; http://www.fsec.ucf.edu/en/publications/html/FSEC-PF-226-91/
> 
> Now I'm trying to convert the heat flux (using same outside temps) through the attic insulation (R-20) compared to heat through a 2x4 (R-13) exterior wall-- *pp.86:* http://www.google.com/url?sa=t&rct=...bC5n6vQVAkslv7g&bvm=bv.56146854,d.cGE&cad=rja But the wall outside temp is 5*F, with *10* W/m2 loss and the ceiling (R-20) with 32*F outside and *37 *W/m2 loss, and 21*F out with *48 *W/m2 loss; almost 5 times more loss and temps are warmer in attic (w. 4cm vents) than wall exterior..... anybody?
> 
> ...


Huh? translate to laymen's terms please


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## Gary in WA (Mar 11, 2009)

It's all temperature differences; http://www.uwgb.edu/dutchs/EnvirGeolNotes/HowEarthWorks.HTM

Warm air enters attic, colder air settles in your blown-in insulation. Convective currents formed by temp difference degrade any ceiling insulation without a cover on top or enclosed venting continuous to the ridge. 

http://www.diychatroom.com/f103/width-insulation-rolls-196864/

Gary


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## High Gear (Nov 30, 2009)

With an infrared gun (Lowes has em cheap) I've seen the temp fluctuations (from air currents in my glass insulation) while aimed at the ceiling and the colder it is the wider the fluctuations.
I'm at min code here with blown R38 glass ...will upgrade to R60 I think and the link about the tyvek covering sounds like a great idea.
Great thread !


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## 225714 (Mar 10, 2014)

joecaption said:


> Not enough. http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table
> 
> Need to check to see if anyone air sealed before adding the insulation that's there.
> Sealing up anyplace plumbing, wiring lighting was run into the attic with spray foam will be a big help.
> If someone added can lights make sure there IC and air tight fixtures. If not your going to have to add some covers.


Can the OP use any type of spray foam?


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## Windows on Wash (Aug 30, 2011)

High Gear said:


> With an infrared gun (Lowes has em cheap) I've seen the temp fluctuations (from air currents in my glass insulation) while aimed at the ceiling and the colder it is the wider the fluctuations.
> I'm at min code here with blown R38 glass ...will upgrade to R60 I think and the link about the tyvek covering sounds like a great idea.
> Great thread !


R38 is code.

There is a diminishing law of return on depths beyond that really but insulation is relatively cheap.

Tyvek does stop the wind washing but if you install cellulose, it is denser to begin with.

FYI...what you have is a Infrared Thermometer.


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