Keep plastic for envelope?

[akpingel]

Currently I have an un-insulated 30x50 shop with an open ceiling/attic. At some point I plan to add a ridge vent and soffit vents, and put in a ceiling and attic insulation. The hot summer is approaching and I think I am going to run out of time and not get it all done this season. I read on here on the GJ that using a simple plastic barrier to separate the attic from the shop makes a huge difference in temperature. Anyone care to share their experience with this? Whenever I get around to putting up the ceiling (probably drywall), could I leave the plastic up or is that a bad idea? I'm in NC where the heat in the summer is a bigger problem than the cold in the winter.
Thanks,
Alex

 

[The Cobbler]

plastic has very little R- value
it does stop air movement tho. I don't think you will see any appreciable insulation value with it

 

[akpingel]

I thought that folks were using plastic more for the fact it keeps the attic air out of the floor space air as opposed to using it for its R value.

thanks,
Alex

 

[NUTTSGT]

I used some plastic on the ceiling when i stored my car in the SIL's garage. I heated the place with a kerosene torpedo heater. It did make a difference holding the heat in. ... but it was an uninsulated garage. . . . something was better than nothing.

 

[Falcon67]

I can tell you that putting in the OSB ceiling and then caulking the joints made a perceptible change in air movement. However, it made little difference in heat - attic runs 120F, 7/16 OSB ceiling underside before insulation 95~100+. Plastic - that would make zero difference in heat IMHO. Reflective barrier - that maybe would make a difference.

 

[akpingel]

Good to know. Im thinking I will proceed by adding ceiling + insulation, left to right, as I get time to do such, understanding that I wont get much benefit until the whole ceiling is done.

Thanks!
Alex

 

[Falcon67]

That's how most of us do it anyway. I would consider doing the ceiling first, sealing it up good, then adding insulation as you can. If it's easier for you to do ceiling panel and insulation at the same time, that's OK too. Whatever works best for you.

 

[NUTTSGT]

30x50, how far are your trusses apart ? If you don't have them 24" OC, you may run into support issues with drywall.

If you put ribbed metal up, they have a fabric type of material that can be put up first to separate blown insulation from the metal.

It may be a possibility for you to use rather than plastic. I don't know but I'm sure somebody else can/will chime in.