Attic Insulation

[fuzeman]

Now here's a topic from left field My other choice on where to ask this was the Chrysler Minivan Forum and you guys lost 

Anyone out there have a coconut full of knowledge regarding insulating attics? I'm in a house, built by my Father in the 1950s, with 1950's insulation which is only 3" or so and I've acquired many rolls of 6" rolls of insulation that has a vapor barrier on one side. I'd like tips on the best way to install the rolls and maybe also answer some of my questions regaring the installation. The house is in the northeast just outside Buffalo, New York so we could use more to put it mildly. I should probably add it was originally a one story and when the family grew Dad added a second story early in the 1960s I guess it would have been. Both stories need insulating.

The present state of the attic is: as mentioned only original insulation estimated to be 3"s and I assume it has the usual paper vapor barrier on the bottom out of sight. It's from the 1950s so I'm concerned about asbestos. One site said if there were shiny flakes in the fiberglass I need to be careful. Is there a test kit out there or a way to find out if it has asbestos? I know I have to get the ventilation right too regarding the soffett vents, hope that's the right term, making sure they are clear for airflow. When the roof was re-shingled the installer did make ridge vents so that part is covered.

How do I deal with the new insulation and the paper on the one side. I know it's not good to have an overlapping vapor barrier so do I remove it, VERY messy, or possibly perforate it so it's not a barrier? If I have to remove old asbestos insulation I guess I'd still need that on though, even though this new barrier wouldn't get under the ceiling joists [ terminology?].

Do I just lay it parrallel or perpendicular to original stuff / joists? If I do this what about the 3" space between layer of new insulatoin and original stuff?

I do want to use the new rolls opposed to blowing in that messy stuff and another issue is there is some stuff stored up there now. I'd really like to keep that up there and had the idea of filling in the 3" space up to top of joist with insulation and buying some styro-foam sheet insulation. Maybe cover that with thin plywood and put the crap on top of that.

There any sense in putting the insulation on the bottom of the roof in between the roof rafters [ terminology? ]?

[ACE]

If it was me I’d use spray in foam style insulation.  It covers every crack and expands as it drys. Way better than anything rolled or fiberglass style.

[fuzeman]

First, that would cost more and I have maybe 100 rolls of 6" stuff that I want to use.
If I did spray wouldn't that compress the old stuff or would it need to be removed.
It's a 70 year old house and making it perfect would be really expensive. Just want to improve it

If it was me I’d use spray in foam style insulation.  It covers every crack and expands as it drys. Way better than anything rolled or fiberglass style.

EDIT- and to reinforce the desire to use the rolled insulation I have, it’s already in the attics.

[ACE]

Well I guess you answered the question yourself. Just put more of the rolled stuff you have. Any is better than none! 

[pembquist]

You can get a decent vapor barrier with paint so you might not have to worry about that. If I was you I would peel the kraft paper off as I was putting down the new stuff. It is probably 6 vs 1/2 dozen whether you put the new stuff down into the joist cavity of the ceiling or go the other way leaving a little airspace, the stuff will sag anyway, you could get more fill if you do a layer inside the joists than a layer crosswise. You really want 11+ inches of insulation in the ceiling especially in upstate NY. The soffit vents if you have them you can put thin plywood or cardboard or these foam or eggcrate paper things that go between the rafters so that their is a space preserved for airflow, alternatively the hip thing now is something like Ventsure or similar vents that you can shingle over. With that kind of venting you can have the intake vent a few feet up from the eave and you don't have to worry about blocking soffit vents but actually you do because of ice dams. Ice dams are another subject but they are related to insulation. As far as asbestos goes you can take a sample and send it to a lab. I didn't know that fiberglass bat was made with asbestos but then it seems like it was used in everything. Look online for a testing lab in Buffalo. The biggest heat loss comes from infiltration which is a fancy way of saying drafts so it is worth sealing any plumbing penetrations and the like with sprayfoam before you lay down the fiberglass. Definitely wear a respirator, (I would recommend you spring for a cartridge one as the paper ones smell funny and get sodden) and for gods sake don't do it in July or August.

[nooby52]

I dont know much about installing insulation in an attic, but as regards possible asbestos exposure: someone else has already suggested sending a sample of the fibrous insulation to a lab I second that motion. Also know that you should be on the lookout of any deteriorating pipe insulation; that could contain significant amounts of asbestos, so be very careful if you se any of that. Some old pipe insulation is a corrugated paper type that may contain up to 80% chrysotile asbestos. Suspect asbestos-containing material should be removed wet, should you decide to remove it. You can do it yourself (there are many good articles online about how to do it safely but I recommend hiring a professional). Asbestos-containing mastics and other non-friable materials in good condition pose no real health risk if left in place and undisturbed. Just my 2 cents.

[Bizman]

Did they use vapor barrier in the 1950's? If not, has the ventilation of your house been renewed to carry any moisture out? If all the moisture has evaporated through the ceiling adding a vapor barrier will cause a very moist attic, rottening any wood and spoiling your breathing air with mould spore.

If you're going to add insulation over the existing stuff there's no need to worry about asbestos. It's harmful only if you move it so that the dust gets into the lungs of everyone in the neighbourhood. Stabilized under a fresh layer of insulation any asbestos is fully safe until someone demolishes the attic.

My personal choice would be either saw dust or rather blowable cellulose wool made of recycled paper and treated "fireproof". They let moisture out.

[pembquist]

Here is a link to some info on vapor barriers https://www.ecohome.net/guides/2299/painting-on-your-vapour-barrier/

[Meatwad]

I have the white fluffy blown in insulation that was put in about 3 years ago, its around 24-30" deep. The previous stuff was that newspaper stuff like 3" deep, the stuff that if you kick up the dust you blow out black boogers the rest of the day. It has worked great on keeping the heat in during the winter

[morfiend]

Soffit vents,you need air flow in the attic.If you insulate make sure you dont plug the soffit vents.If you dont have vents put them in! They make a foam vent material that fits between the rafters,install them where the vents are or cut your own soffit vents then insulate as much as you can.

  I have about a foot and 1/2 of blown in rockwool/fiber insulation,I had my walls done as well.It required drilling and filling the wall cavities,spray foam would have been my first choice but just too expensive and there's a chance of blowing out a wall inside so it was fiber filled.

  Just put the rolled stuff in and wear a mask and try not to disturb what already there. If you have an inspector test for asbestos and it's found,well thats gonna cost you big time so I would just be careful when laying in the new insulation.

 I had asbestos tiles on the kitchen floor,we were advised to not disturb it and just lay a new floor over it. That said if you're really concerned about it I would have an inspector check it. Not sure how it's handled in your state Fuze but up here it can be a costly thing to rectify.

YMMV.