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-   -   Attic insulstion kraft side up (http://www.diychatroom.com/f19/attic-insulstion-kraft-side-up-93071/)

Atskodinski 01-21-2011 09:27 PM

Attic insulstion kraft side up
 
Just found out tonight my attic's bottom layer of fiberglass insulation is installed kraft side up. On top of that is a 4-6" layer of cellulose blown in. Any recommendations about how to deal with the upside down fiberglass? I'm hoping it doesn't involve ripping out all the old and correctly putting in new.

gregzoll 01-21-2011 09:35 PM

Tear off the Kraft paper and put the blown in back on top. Keep in mind, that you may be better to just wait until Spring, and just pull out all of the Fiberglass batts, and blow in new Cellulose or Mineral Wool Insulation for min. R-49.

Atskodinski 01-21-2011 10:10 PM

Quote:

Originally Posted by gregzoll
Tear off the Kraft paper and put the blown in back on top. Keep in mind, that you may be better to just wait until Spring, and just pull out all of the Fiberglass batts, and blow in new Cellulose or Mineral Wool Insulation for min. R-49.

Wondered If just tearing off the kraft paper would be an option. To me, that would be the easiest option and I could just blow or lay in new insulation as needed. Of course, I no longer would have a vapor barrier.

gregzoll 01-21-2011 10:48 PM

Leave alone, and take care of it come Spring before it gets too hot to work up there. Problem is, once you start moving the Blown insulation away from the Batts, you will have to have more blown in to replace. For the costs to rent the equipment and materials, a crew of two or three can have it done in about two hours for the same amount. Get some bids now, because crews are looking for work, and you may be able to get a good price on fixing the insulation situation.

Atskodinski 01-21-2011 10:55 PM

Quote:

Originally Posted by gregzoll
Leave alone, and take care of it come Spring before it gets too hot to work up there. Problem is, once you start moving the Blown insulation away from the Batts, you will have to have more blown in to replace. For the costs to rent the equipment and materials, a crew of two or three can have it done in about two hours for the same amount. Get some bids now, because crews are looking for work, and you may be able to get a good price on fixing the insulation situation.

Honestly, I'm not planning on doing anything with it at the moment. I've got enough else to keep me busy. What risk am I running not doing anything at all? God only knows how long it's been like this. Bought house year ago and built in '56. Thanks for advice on bringing in a crew. It does strike me as the sort of thing that a pro could do way quicker than me, not to mention better. Can't imagine the cost being that much greater either

gregzoll 01-21-2011 11:36 PM

You could either spend a weekend with a few buddies, with one or two that know how to do it, and then split a case of good beer at the end of the day, or get a crew in and out, and have them clean up afterwards, and have them gone in no more than three hours. If I had the time myself, yes I would call a few favors, but personally, I am in the same boat with the insulation in the attic, but mine is needing about 3-4 more inches up there, plus some leak sealing , so it is a weighing of options.

Home shows are coming up, so it is a good time to pick some brains with companies that do this for a living.

jklingel 01-22-2011 12:45 AM

I'm w/ greg. Get the facing off asap, weather permitting. I'd hit it before any frozen condensation melts. Forget about the vapor barrier; you probably don't need/want one anyway. While digging around, air seal the H out of the place. That is 10 times move valuable than worrying about a vb. From what I can deduce, the FG is not too bad in an attic IF covered over w/ cellulose; lots of it.

Atskodinski 01-22-2011 04:17 PM

So is an attic vapor barrier not that necessary? I'm in Southern Indiana. What I want to do is rip off all the kraft paper, seal air leaks and then just blow in enough cellulose to get to my desired R value. I lose a vapor barrier doing so but you make sound as if it's not all that necessary?

Mr Chips 01-22-2011 09:47 PM

Before you look at hiring it out, check out your local big box store. usually, if you buy 20 bales, they will loan you the machine at no charge. it's a little messy, but a super easy DIY job

jklingel 01-23-2011 12:20 AM

Vapor barriers are becoming a thing of the past in all but the coldest places (typically zones 7 and 8, & some hot/humid places). Even up here, they are not being used 100% of the time, though they are apparently pretty safe (my house has a vb, but the new one we are building soon will not have one. I built in '80, and "everybody does it"). Esp if you ever run air conditioning, vb's can be dangerous. Many people get by using one where they really shouldn't, apparently because their houses are pretty leaky. Tight houses were not standard till recently. Yes, AIR barriers are where you need to focus. Your code probably says that you need a vapor RETARDER of one perm or less, which can be addressed w/ the airtight drywall approach and other methods. Your inspector may say "you need 6 mil poly" (perm 0.06, very vapor resistant), like one up here did a month ago, but ask to read the code; it does NOT likely say "vapor barrier". Neither Frb nor Minn follows a "gotta have a vb" code, and they tend to be pretty cool, I hear. Go to buildingscience.com or greenbuildingadvisor.com and do a search. You'll find enough there to keep you reading well past the time you should start building! :laughing:

pyper 01-23-2011 06:28 PM

The house we're buying has the insulation upside down too (probably put in that way when the house was built in 1970. Where we live (S.C.) it never gets cold enough to freeze in the attic. I'm wondering if there would be any real problem with just putting cellulose on top of it.

gregzoll 01-23-2011 07:58 PM

Not really. Better than going through all of the work to rip out the old and blow in Cellulose or Mineral Wool.

jklingel 01-24-2011 12:05 AM

Keeping that vb in the middle is iffy. Check w/ locals, as I don't know if SC is a "hot/humid" place. I think Mike Chandler (sp) on greenbuildingadvisor.com builds down that way and is very familiar w/ your climate's special needs. I'd read there, too. j

Atskodinski 01-24-2011 04:54 PM

Quote:

Originally Posted by jklingel
Vapor barriers are becoming a thing of the past in all but the coldest places (typically zones 7 and 8, & some hot/humid places). Even up here, they are not being used 100% of the time, though they are apparently pretty safe (my house has a vb, but the new one we are building soon will not have one. I built in '80, and "everybody does it"). Esp if you ever run air conditioning, vb's can be dangerous. Many people get by using one where they really shouldn't, apparently because their houses are pretty leaky. Tight houses were not standard till recently. Yes, AIR barriers are where you need to focus. Your code probably says that you need a vapor RETARDER of one perm or less, which can be addressed w/ the airtight drywall approach and other methods. Your inspector may say "you need 6 mil poly" (perm 0.06, very vapor resistant), like one up here did a month ago, but ask to read the code; it does NOT likely say "vapor barrier". Neither Frb nor Minn follows a "gotta have a vb" code, and they tend to be pretty cool, I hear. Go to buildingscience.com or greenbuildingadvisor.com and do a search. You'll find enough there to keep you reading well past the time you should start building! :laughing:

Perhaps my terminology is iffy. Vapor barrier and vapor retarder are two different things? The kraft paper attached to insulation is a vapor retarder and codes require at least a vapor retarder, not necessarily a vapor barrier. Am I saying this correct?

If that is the case, just ripping off the kraft paper doesn't completely solve my problem because I still would need a vapor retarder, which would essentially require new insulation put in.

As a side note, it seems many people have a situation similar to this. Has the philosophy changed over the years where it used to be proper for kraft paper to face up?

Arthropod 01-24-2011 09:28 PM

vapor barrier use different in different climates
 
In cold climates insulation with vapor barriers/retarders is put in towards the interior. In warm humid climates like South Carolina the barrier is often put in towards the outside. The idea is that as air with moisture in it moves from a warmer area to a cooler one (as in a layer of insulation) the air cools down and can hold less moisture. If it cools down enough, the excess moisture can condense onto the cold surfaces around it e.g. the insulation or framing members. This can cause mold or fungus problems.

In Indiana during the winter, the humid indoor air moves through the ceiling (even tightly installed sheetrock) and can condense before it gets through the insultion if it's cold enough. It may or may not be a problem depending on whether it stays wet enough long enough to cause problems. Look for signs of mold/fungus within the insulation along the framing members. Depending on how long ago the extra layer of insulation was installed, signs may not show yet. It could be that it doesn't cause much problem if it doesn't get too cold where you live or if your attic is well vented, although I would expect Indiana to be humid and cold enough that it would cause trouble eventually.

Long ago I read about a general rule of insulating in cold climates that said if the vapor barrier is within the inner one-third of the insulation depth (or innner third of insulation value if there are different types of insulation involved), then water will seldom condense out of the migrating air because the air doesn't get cold enough before it hits the barrier. That is for a good vapor barrier that truly keeps the moisture from going farther. Your vapor barrier on the insulation is probably not blocking flow of air past the edges of that insulation along the framing members and so is more of a vapor retarder. I would expect problems to develop along the framing members near or above the level of the vapor barrier if anywhere. If it is blown in cellulose above the batts, the chemicals in the cellulose can help deter mold/fungus growth. I would expect if you remove the barrier and reinsulate with blown-in you would not relieve the problem of moisture condensing in the insulation, but the condensation might not concentrate along the framing edges and so might dry out quicker and cause less trouble. If it isn't causing problems, I would do nothing.

In South Carolina the problem may be in the summer when warmer air moving into the house hits cooler surfaces and the water condenses. Therefore, the barrier is put on the outside. Where the barrier is put depends on local climate.


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