I live in CT, in a 100+ year old house. We have hot summers and COLD
winters. I believe that our attic floor was previously insulated, as
our house winter temperatures are easily controlled. Still I cannot
easily verify that insulation. nor amount/ depth - as there is
hardwood flooring in place.
There is no insualtion, on the attic roof insides. I would like to add
insualtion, and looking for guidance. What should I buy for
insualtion, which side facing the roof. Do I need to take efforts, to
provide any air flow ? (There is no roof peak vent). Should I use a
vapor barrier, over the new insualtion?
Would there be any issue/ concern, if I then put drywall over the
insualtion, to make the attic into a finished room?
Thanks for the advise offered. - joe
From your description there will be no gain from insulating the rafters
unless you're going to finish and occupy that space . I'd only insulate the
actual finished space , that is up the rafters to ceiling height then across
the ceiling . Use the plastic trays they make to go between rafters to
insure convective airflow , and your current attic venting system should
work just fine . I wouldn't finish all the way to the peak , leave a space
for airflow to whatever venting you currently have . Most insulation carries
a vapor barrier , which always goes toward the occupied space .
On Thursday, December 18, 2014 9:41:18 AM UTC-5, Terry Coombs wrote:
It's unusual to have an attic floor done in hardwood, yet the rest of the
attic is unfinished. Depending on the space, it may not be worth finishing,
unless you wind up with something reasonable. Depending on the rafter widths,
he may want to sister support wood for sheetrock to the existing rafters
thereby giving more room for insulation. Otherwise, with say 2x8' rafters,
by the time you put those plastic baffles for airflow in, you only have ~6"
of insulation, which isn't much for CT. But of course with the sistering,
you would lose more headroom.
Also, he said there is no roof peak vent. How about gable vents?
Soffit vents? If it's an unfinished attic, there should be adequate
venting consisting typically of soffit vents together with exit venting
up high. You said his existing vent system should work fine, but he
never said what, if any, there was.
Your post isn't entirely clear. You plan to finish
the attic off? If not then you should figure out
what's in the floor. You may not need to insulate
the rafters. If you are going to use the attic as
living space you should have a ridge vent put in
and soffet vents. (Or you can build knee walls
and leave the eves unfinished. In a house that
old there's plenty of draft so that you really
wouldn't need soffet vents. But you should
insulate the knee walls.)
Put in fiberglass batts and cover with plastic
sheeting before the drywall goes on. I like to
use the faced insulation and then cut some
of the facing away so that moisture isn't trapped
between that and the plastic. You don't need
facing. It's just easier to put up that way.
to be an air space between the roof and the
fiberglass. You can plan the batt size for that,
use the corrugated fillers designed for the purpose,
or whatever makes sense. The idea is just that you
need to allow for air flow. The roof is pretty much
a moisture barrier. If you put another moisture
barrier on the inside then you need to allow airflow
under the roof. Thus the soffet and ridge vents.
Otherwise it's likely the roof deck would rot over
|I live in CT, in a 100+ year old house. We have hot summers and COLD
| winters. I believe that our attic floor was previously insulated, as
| our house winter temperatures are easily controlled. Still I cannot
| easily verify that insulation. nor amount/ depth - as there is
| hardwood flooring in place.
| There is no insualtion, on the attic roof insides. I would like to add
| insualtion, and looking for guidance. What should I buy for
| insualtion, which side facing the roof. Do I need to take efforts, to
| provide any air flow ? (There is no roof peak vent). Should I use a
| vapor barrier, over the new insualtion?
| Would there be any issue/ concern, if I then put drywall over the
| insualtion, to make the attic into a finished room?
| Thanks for the advise offered. - joe
Presumptive of me ... but there's surely some kind of venting , probably
gable and soffit . And I'd like to change something - insulate only the new
space , that is the wall framing and ceiling , rafters only if they become
framing for the newly enclosed space . And still use the plastic channel
thingies in any insulated rafter space . And if there is no venting , he
needs to add some - typically turbines or peak vents and soffit vents in a
On 12/18/2014 8:16 AM, email@example.com wrote:
Your first issues are to stop all air pathways from the heated space(s)
to unheated. Insulation of the fiberglass type does virtually nothing
if there's any air movement at all thru it.
There are real possibilities of introducing condensation surfaces by
have double layers of insulation in attics in particular. Since you
apparently have an insulated ceiling now/future floor, you need to be
careful you don't turn that into one of those areas where cold
infiltration along the edges of it allows condensation since if you
finish above it will now also be heated space.
As another said, if you are going to finish the attic into heated living
space, likely it will be more efficient if there's the height in
sidewalls to build another ceiling rather than insulate clear to the
roof line itself. If you're _NOT_ going to add heated space then you
want to simply add more on what is now the attic floor.
You can guesstimate what's there pretty well by looking at the thickness
of the opening to get up there. If it's a framed hole w/ a ladder,
should be relatively easy to see what the ceiling/floor joists are. If
there's a finished stairway, still should be able to get a
measurement/estimate of the distance between the ceiling below and the
floor above -- subtract for the flooring and ceiling thicknesses and you
should be able to tell if 2x4, 2x6, 2x8 (nominal sizes) was used.
Assume either blown or fiberglass or perhaps rockwool depending on when
you think such insulation may have been added and whether know if the
flooring was in place first or not and can get at least a reasonable
guess of what the R-value will be...
Also whether you've got enough floor there to actually convert to living
space without additional structural work...
On 12/18/2014 9:16 AM, firstname.lastname@example.org wrote:
bungalow with finished basement and upstairs. Thus, I had my house
(attic and rim joists) insulated with spray foam. I used open cell foam
on the roof deck and closed cell in the foundation rim joist. There is
probably a 3 to 4 degree difference from the basement to the upstairs in
summer and winter. Hot air will always rise, but a 4 degree difference
is nothing when it used to be 10 +. With proper insulated windows, my
entire house went from an absurd out of range efficient drain to one of
the top 4% in this region, based on a blower door test and infrared
reading before and after.
Overall, I was shocked at the low cost to have this done (at least in my
area). Just thought I'd share in case you want to consider a different
email@example.com posted for all of us...
I don't mean to be snarky here (well I do) but this has been discussed
sooooo many times. There are are soooo many variables in YOUR attic.
Why don't you do some Goggle or tube research FIRST, then come back with
On Thu, 18 Dec 2014 09:16:16 -0500, firstname.lastname@example.org wrote:
From the many useful posts, in response to my post. I realize I did
not fully describe my attic situation.
The house, being over 100 years old does have hard wood (maple? )
floors. The area with with over 8 feet ceiling clearance is a ~ 20 x
40 feet area , then with sloped sides.
I live on Long Island Sound. Tthe views from the attic are the best
we have - which is why I may finish the room. I now use part of the
attic, for a workshop (rest now storage). In the summer, it is often
too hot to work there , indeed the heat permeates the entire house. I
thought that the ceiling insulation would limit the summer heat issue,
while improving the winter heating.
I agree that the attic floor boards are likely 2 x 8. where the
current insulation is located. The roof rafters are 2 x 6 (note,
these are near full demenions. vs current board standards).
On Friday, December 19, 2014 12:03:45 PM UTC-5, email@example.com wrote:
If the new ceiling is going to follow the roof rafters, you have two
considerations. One is the existing 6" rafters are only going to allow
for about 4.5" of insulation, which isn't much.
The rest of the space will be taken up
by the ventilation baffles/channels that need to run from the eaves,
where hopefully there is venting, to the ridge, where you'll have a
ridge vent. The other problem is that nailing sheetrock to the rafters
is going to increase the load and depending on the span, 2x6 may no
longer be adequate. Both of those could be solved by sistering the
existing rafters, giving you more strength, more room for insulation.
It's not surprising that it's too hot to work up there. It's
a totally unfinshed attic and I would think even on a moderate spring
day it would be 100F.
>> I went shopping for an auto battery this week and noticed that all of
>> them once again have removerable caps for inspecting and adding
>> distilled water when required.
>> That is the way the batteries used to be many years ago, but then they
>> changed to "fill-less" batteries some time in the past. The fill-less
>> batts didn't have removal caps to add water. Now we are back to the
>> fillable batts.
>> What caused the change back? Anyone know?
> I didn't know there was a problem. None of the batteries I've purchased
> have ever lacked removable fill caps.
| I thought that the ceiling insulation would limit the summer heat issue,
| while improving the winter heating.
Yes. So maybe you want to insulate it. If there
are further questions they can be answered, but
you already have directions on how to proceed.
Insulation in the floor won't hurt. It will just be
sound insulation. If I were you, before finishing
off the ceiling, I'd also consider putting in a ceiling
exhaust fan for summer, so you can pull in cool
air. Once you're done the attic won't cook the way
it does now without insulation, but heat rises, so it
will still probably be hotter up there than in the rest
of the house. A good vent fan in the attic will also
help cool off the whole house quickly on summer
I have our attic finished. First thing I do when I
get home on summer evenings is turn on exhaust
fans in the attic window and a second floor bedroom
window. With windows open on the first floor the
whole house then gets an air change.
On 12/18/2014 9:16 AM, firstname.lastname@example.org wrote:
Not enough information. First: You must find out _if_ you already have
insulation under your flooring. Second: You must verify _if_ the area
above the flooring is conditioned space.
Planning on how to insulate at this point, is wasted effort without the
While I have never removed any of the attic floor boards, I am most
confident that there is indeed insulklation. I can easily heat (cool)
the 1st two floor's ambinet temps, with no excessive heat loss. I want
to insulate the attic ceiling to limit the heat gain (summer) / Loss
Note: It is not my current intent to heat/ cool our attic area. If I
ever finish the area, I do have ezisting heat and AC ducting available
I have eight "swing open" attic window panels, that I open in the
summer months. While using floor fans, the attic temp rise (hot day)
can still be most uncomfortable - when I use it as my workshop.
On 12/20/2014 6:59 PM, email@example.com wrote:
If you decide to insulate the rafters. It is important to have adequate
ventilation between the insulation and sheathing. If not, you will get
condensation in the winter and rot the sheathing. There's no what if's,
the fact is you will. By the time you see the condensation, it will be
only after the sheathing is saturated and will no longer absorb the
If you're going to convert attic into occupied/living space might it make sense to replace the roof rafters with wider ones(2x6" repl with 2x8") to allow thicker batts and still have 1-2" of space between the batts and the roofing itself?
My roof is(at best) 2x6" rafter beams, so I couldn't get thicker than 4" fiberglass batts in there if I were preparing for occupation.
Styrofoam comes to mind, didn't think of that.
And a general rule for attic insulation: A tight upper-most ceiling plane(no cracks or gaps) plus sufficient insulation = the best cure for drafts.
I crack up when I see folks fall for that plastic saran-crap they place over their windows every autumn, or stuffed draft-stoppers they place at the bottoms of exterior doors! Stopping drafts begins at the top of a structure, not at the ground level.
Tony Hwang wrote: "- show quoted text -
What is draft? Convection(venting) and air leakage. It is two things,
No? Spray foam is an excellent for sealing and insulating. "
At first appearances, it is cold air leaking in to replace heated air rising through gaps overhead and or insufficient insulation.
Yes, spray foam could be used to plug those gaps, keeping heated air in and reducing stack effect.
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