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baltimorebob 12-29-2011 10:51 PM

Attic insulation
 
I have a 40 year old house with NO insulation in between the rafters in my attic ceiling. The floor of the attic is 20% covered with plywood right now and I would like to expand that to about 80% for storage purposes. The entire attic floor is filled with that cotton candy like insulation (sorry for not knowing the proper name)

I have two purposes for adding insulation to the attic.

1. Some areas of the ceiling are below 6' and the roofing nails stick thru, threatening damage to my head more and more everyday

2. Adding some more heat up there in the winter would help save a bit in heating bills and not require me to use a jacket to get something out of storage.

Again, I am not looking to do the job 100% perfect, just accomplish the two tasks above.

My thought was to buy some of that 2'x4'x1inch R8 foam panels from home depot and just push them into the roofing nails (easy no?) thinking that even if they are not sealed, it should still provide some insulation. I have seen articles about shooting some of that foam around the edges to seal it up, but start getting confused about if I really want to seal my attic up that much or not (moisture and what not)

Can anyone give me some advice?

Thanks in advanced

Bob

jklingel 12-30-2011 12:21 AM

I'd suggest you spend some time reading on greenbuildingadvisor.com and buildingscience.com. What you are describing, if I am reading correctly, is a hot roof, and that needs to be done to specs. Your best bet is probably going to be sprayed in closed cell foam, as it acts as an air and moisture barrier, as well as insulating. Anything that does not air seal/vapor seal well may lead to condensation on your roof sheathing, and rot. This, IMO, is not a time to go half way. Good luck, and watch those nails; one puncturing your skull may be the last one.

Windows on Wash 12-30-2011 06:54 AM

Quote:

Originally Posted by baltimorebob (Post 807015)
I have a 40 year old house with NO insulation in between the rafters in my attic ceiling. The floor of the attic is 20% covered with plywood right now and I would like to expand that to about 80% for storage purposes. The entire attic floor is filled with that cotton candy like insulation (sorry for not knowing the proper name)

I have two purposes for adding insulation to the attic.

1. Some areas of the ceiling are below 6' and the roofing nails stick thru, threatening damage to my head more and more everyday

2. Adding some more heat up there in the winter would help save a bit in heating bills and not require me to use a jacket to get something out of storage.

Again, I am not looking to do the job 100% perfect, just accomplish the two tasks above.

My thought was to buy some of that 2'x4'x1inch R8 foam panels from home depot and just push them into the roofing nails (easy no?) thinking that even if they are not sealed, it should still provide some insulation. I have seen articles about shooting some of that foam around the edges to seal it up, but start getting confused about if I really want to seal my attic up that much or not (moisture and what not)

Can anyone give me some advice?

Thanks in advanced

Bob

Bob,

You are getting ready to open a can of worms if you don't do this properly.

Converting an unconditioned space into a conditioned space requires changing the insulation and envelope layer placement as well as accounting for moisture management and making sure that you don't create a condensation issue as well.

The vented attic is a time tested and well proven design. If you are going to effectively create a conditioned zone out of the attic, it is going to cost a decent bit and require more than foam against the sheathing.

Posting up a picture will get you more directed feedback and pointers.

baltimorebob 12-30-2011 03:05 PM

Attic insulation
 
First, I appreciate all the feedback, but I think you are thinking I was going to 'seal' up the attic. Again, my main purpose was to protect my head from the nails. If I don't seal around the boards, leaving a 1/2inch on each side will it still cause venting problems? Also, before the summer comes I was planning on putting up a solar powered exhaust fan.

Also, I was only planning on putting the boards up in the 1/2 of the attic that will have the storage space, the other 1/2 of the attic will still be normal.

I will try to take some pictures this weekend for better clarity.

Bob

HAPPY NEW YEAR ALL! :jester: :thumbup: :laughing: :no: :yes:

baltimorebob 12-30-2011 03:44 PM

Almost forgot
 
Sorry, forgot to add, if everyone is agreed that I should NOT do the insulation because of too many problems, then I would like a few recommendations for not getting a roofing nail in my head. :bangin::cursing:

jklingel 12-30-2011 04:39 PM

plywood or paneling on the rafters.

Minich 12-30-2011 05:15 PM

Seems like an awful lot of work just because of nails. I'd listen to the guys talking about insulation and airflow. Could you just find an efficient way to cut offending/protruding nail spikes at the base? Seems to me that'd solve your problem, cost basically nothing, and probably not take more time than what you were already thinking about. I wouldn't bend the nails over, by the way, I think you'd regret that.

jklingel 12-30-2011 05:25 PM

Good idea on nipping nails, but I'd be a little concerned about wiggling them whilst doing so, and maybe loosening them. Dunno. Throwing up a few pieces of cheap paneling seems pretty easy, but I ain't there.

ratherbefishing 12-31-2011 11:50 AM

http://www.coopersafety.com/product/...FQ4j7AodxkGqnA

Sorry. Too easy. Couldn't help myself.

Windows on Wash 12-31-2011 03:58 PM

Quote:

Originally Posted by baltimorebob (Post 807487)
First, I appreciate all the feedback, but I think you are thinking I was going to 'seal' up the attic. Again, my main purpose was to protect my head from the nails. If I don't seal around the boards, leaving a 1/2inch on each side will it still cause venting problems? Also, before the summer comes I was planning on putting up a solar powered exhaust fan.

Also, I was only planning on putting the boards up in the 1/2 of the attic that will have the storage space, the other 1/2 of the attic will still be normal.

I will try to take some pictures this weekend for better clarity.

Bob

HAPPY NEW YEAR ALL! :jester: :thumbup: :laughing: :no: :yes:

That should be fine. Make sure the tops and bottoms of the rafter bays are open by a couple of feet.

Make sure the soffits or gables are unobstructed and you will be fine.

Make sure the solar powered attic fan is properly sized and does not pull conditioned air from the living space below otherwise you will be cooling off the attic by blowing in conditioned air and that is not a good way to go at it.

baltimorebob 01-01-2012 01:48 AM

if I could get some education please
 
Again, thanks for all the input. Also thanks for the hardhat link, gave me a big laugh. :laughing:

I am probably going with the panel idea, sounds easy.

Just out of curiosity though, what is the problem with pushing the foam panel up against the nails if I don't seal it and if only 1/2 of the attic is done, allowing for alot of airflow?

My assumption is that water/moisture would build up behind the panel causing problems with the wood? Again just trying to educate myself.

Thanks again everyone,

Bob

Gary in WA 01-02-2012 12:04 AM

Don't clip the nail exposed below the sheathing, it is long to meet building code, otherwise they could work themselves out or be torn off in a high wind. http://publicecodes.citation.com/ico...005_par007.htm

http://www.buildingscience.com/docum...bout-diffusion

Gary


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