Insulation, Radiant and Vapor Barriers - New Insulation Installation

hi folks....

during the recent renovation of my circa 1939 cottage (here on long island, ny) upon removing the drywall and layers of paneling, i was not shocked to find that there was no insulation in the house, unless you include the various spots that were stuffed with newspaper. :wall:

the house is 2x4 studding and am planning on putting r-13/r-15 in the exterior walls. the exterior is being pulled of simultaneously and being replaced with 1/2" ply, and tyvek'd.

for the interior vapor barrier my intent was either a 4 or 6 mil poly.
i used black in the crawlspace rat-slab project, and just wondering if there was a difference in either black or clear for this particular detail?

thanks much!!

http://www.eere.energy.gov/consumerinfo/factsheets/bd4.html

This is a site on Vapor Barriers. There is probably not a difference between the moisture barrier you installed in the crawl space and other types of plastic sheets other than the black sheets are probably more durable.

What you intend to do with your walls is fine.

thanks resercon...
i'm glad you responded, because i'm confident in the information in your other postings throughout the forum as well. :D

my house is a one-floor cottage with a gable roof.
i have vents on either side in the attic, and will eventually add ridge vent when i redo the roof.

the ceiling joists are approx 24" o/c and was planning on doing an r-30 up there. my question is (and pardon me if it seems ridiculous) there is no need to insulate up top against the roofing sub, in between the rafters as well, correct??

thanks,
--j

http://wsuonline.weber.edu/course.cmt.1210/Lecture/Vent/Vent_Index.html

This site give a fairly simple lecture on the purposes of attic ventilation. Please pay close attention to the ratio of vents (High/Low).

http://www.popularmechanics.com/home_improvement/home_owner_clinic/1275281.html

If your cottage does not have the overhangs (soffit/eaves) this site illustrates one way of accomplishing it.

I personally do not care for ridge vents. My position is the less penetrations you have in your roof, the better. You can accomplish adequate free venting with Gable and Drip Edge vents.

thanks!
am going to take a look right now!

yeah, i think i'd have to agree with you re: ridge vents!!
thanks again.

--j
:thumbup:

thanks!

those links were terrific and provided me with a ton of 411!!

fortunately i do have soffits, and currently gable windows/vents up there.
the windows are out, but i plan to recalculate as per that doc. just exactly what i need!!

thanks again!!! :cool:

We use clear poly so you can see the studs and rafters better dont have to feel for them. Ridge vents are out down here. From the storms water did blow in-- a lot

ED :D

Thanks Ed!

another response from someone i was hoping to hear from.... :D

yeah, that makes sense with the clear :confused:

i don't think that it would have mattered either way in the rat-slab either.
from what i read, the black was to block light, and really to prevent the growth of unwanteds, but being that i poured a slab over it, i think in the end it was insignificant...

clear it is for the walls!!

as i ponder another perhaps silly question... you wouldn't want to put this on the ceiling, would you? between the rock and insul.?

We have always put poly on the ceiling and the walls then the drywall. When it is cold out. We found out the hard way, way way back. Dont tape or paint any drywall till you have the insulation up on top of it in the attic.


ED :wall: :wall:

makes absolute sense.

so if i'm reading you correctly, you would recommend putting the v/b up on the ceiling, then the rock.

then drop the insulation down from above, rather than stapling it up?

actually i should have been more specific.

the ceiling i'm referring to is not the rafters in the attic, i meant the joists.
not sure if that was clear.

Id put the insulation up and staple it then the poly over that.you will have a better fit. With the home open we put the foam rafter vents up then like 5' or 6' of a paper faced R 30 from the walls in. Most of the time the rest is all blow in. like to use cellulose insulation for that if we can.

ED

basement are crawl space the joist are over??

ED ;)

ok that question was slightly confusing but i think i got what you were :confused: asking....

80% of the house has basement
20% has rat-slabbed crawl space

If you dont have a good V/B down under the slab Id put one over it and insulation on all the walls and around the belt board on the sill plate in all the joist. There in the crawl space.

ED ;)