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r-11 in attic


gearhead59's Avatar
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04-16-11, 03:58 AM   #1  
r-11 in attic

I just bought this house and I'd like to improve my insulation in the attic, it has one layer of r-11 faced insulation in it, with a couple of extra strips of r-19 thrown on top. They had one of the extra strips stuffed in the soffit, I pulled that out. What would be the best way to do this, removing the old and junking it is no problem. My son works for a local insulation guy, and he says just blow some of this new stuff he has, in on top of it. These guy's he works for are kinda "fly by night", so I'm on here asking your opinion of the best way to do this ! I don't want to get all "anal" about it either, but I want it done right ! I do live on a lake, and the moisture level may be a factor, everybodys house around here has moss on the shingles. House was built in 1953, FYI.

 
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04-16-11, 04:37 AM   #2  
R-11 in an attic is like trying to water a 400 acre field with a garden hose. It is basically worthless. You say it is faced. Is the face toward the living space? The second layer, is it faced? It should not be. If it isn't, leave it all and insulate over it all, installing proper soffit baffles to keep the soffits free of insulation and the air moving over it all. Little more prep work, especially with the soffits and pulling the second layer if it is faced, but all doable via blow in if you want. I am not sure what "new stuff" they have, so I am reluctant at that. I would install a ridge vent to give passive complete ventilation to the attic once the soffits are opened up.

 
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04-16-11, 05:15 AM   #3  
Yes, it is faced, both layers, I will get rid of the second layer, I know this is wrong. First layer is face down, and stapled to joists. These guys my son works for always install the soffit baffles, and it has ridge vents. My son just now told me that the "new type" insulation they are using is blown-in fiberglass with an r value of 55-60, at 13" of depth, (that's what my son is telling me, not sure if he knows exactly,... yet). Would it be best to just get rid of the r-11 old stuff, and just blow in the whole thing ? It's probably not real new to you, ( the blown-in insulation I'm refering to), we live out in the boonies and we're probably 10 years behind ya'll in technology, ha ! Sounds like my son may be working for a guy that knows what he is doing, so I may have him shoot me a price ! Any more tip's or ideas ?


Last edited by gearhead59; 04-16-11 at 05:33 AM.
 
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04-16-11, 06:06 AM   #4  
I think you have it by the horns. Yeah, pull the top layer, but if the bottom is stapled and is not in bad shape, crushed down, etc, I'd just blow it over. It will disappear. I can't comment on the R value of "new stuff", but some of the others may have more info than I. I'd get a price, anyway!

 
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04-16-11, 07:18 AM   #5  
The step not being considered is the air sealing before the new insulation goes in, especially fiberglass since it does little to restrict air flow. The number one source of heat loss is most often air leakage. Adding all of that insulation without sealing the leaks would waste half of the job.

I'll attach a link below for reference to help deal with the sealing. It opens slow but is good.

As for the new type of insulation, I haven't run into it as yet, but somewhere between possible and overstatement. High density fg batt insulation can reach R-4.2 per inch. Here they are suggesting 4.2 to 4.6 per inch. Pink or blue rigid foam board only offers R-5 per inch and certainly no air circulates through that material.

The baffles you are talking about provide a path from the soffit into the attic. There is another baffle, sometimes combined with the first, that blocks the end of the insulation so incoming air will not wash through the fiberglass or actually blow it away from the eaves.

Where ever your attic entrance is, hatch or stairs, you will need to build a barrier around it to hold the insulation away and provide a surface to place an air tight insulated cover.

If you have any recessed lights in the ceiling below, make sure they are IC (insulation contact) and air tight rated. Be sure all exhaust vents continue to the outside and do not trap moisture. Example is the flex duct going up and down will allow condensation to collect in pools inside the duct. Insulated metal ducts should be used.

If you have any air conditioning or heating ducts in the attic, they should be sealed and insulated.

One last addition, when that much insulation is being added, there will effectively be no more access to anywhere in the attic, at least without significantly reducing the quality of the insulation. Typically, blown in fiberglass cannot be pushed away and then pulled back and perform the same. Mark from above anything that gets buried and consider a raised cat walk above the insulation.

http://www.efficiencyvermont.com/ste...ide_062507.pdf

Bud

 
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04-16-11, 07:24 PM   #6  
Wow, talk about detail ! Thank you for all the information guy's ! I'll research the link and use ya'll's great advice to complete the job correctlly. I've got till about September to get it done now, so I can take my time and do it right ! Thanks again !

 
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