# How to attack this... (insulation related)



## CoconutPete (Jan 22, 2010)

Well, leaving for work the other day I noticed the dew on the roof had evaporated in one spot faster than the rest of the roof and I found that funny.

Luckily it was fairly easy to investigate since the spot on the roof directly corresponds to the crawlspace behind the wall in our guestroom.

As you can see the insulation there is kind of a mess.... hence... I'm here asking for advice.

What do you think? Tear out & start over? Or try to fix this mess?


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## Ron6519 (Mar 28, 2007)

The insulation should be on the door wall, under the plywood behind the door and the ceiling. There should be no insulation in the roof rafters behind the door.
Check out the Owens Corning site for a visual of the proper installation on the second floor.
Ron


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## Gary in WA (Mar 11, 2009)

Use rigid insulation board or a house wrap on the attic side of the knee wall and insulate the attic access door, as mentioned already: http://www.simplesavings.coop/simplesavings/SIMPLESAVINGS knee walls.pdf

Gary


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## CoconutPete (Jan 22, 2010)

Interesting. Was it done differently back in the day? The knee wall right now has absolutely zero insulation on it, but the roof rafters is where it was all insulated. It's a cape cod from 1930.

I guess a side question becomes: Tear out the old insulation in the picture?


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## Scuba_Dave (Jan 16, 2009)

My roof rafters are insulated w/R25
My knee walls are insulated w/R13 to R19
My preference is to insulate both
My storage area stays warmer then outside
Since there is living area below the storage area it makes sense


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## CoconutPete (Jan 22, 2010)

Scuba_Dave said:


> My roof rafters are insulated w/R25
> My knee walls are insulated w/R13 to R19
> My preference is to insulate both
> My storage area stays warmer then outside
> Since there is living area below the storage area it makes sense


Which one do you like better:

A: Try to "mend" the insulation that is in the rafters and then insulate the knee wall.

B: Tear out the insulation in the rafters and start fresh both there and in the knee wall.


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## Scuba_Dave (Jan 16, 2009)

That depends upon the rafter size & existing insulation
Also if the soffit/ridge are vented & you have rafter vents installed

R25 was installed by a prior owner in my rafters
Does not make sense to me to rip mine out to go to R30

But if you have R13 & can fit R30 that would be much better


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## CoconutPete (Jan 22, 2010)

I'll inspect it more thoroughly tonight.

Only the first 5 feet have come apart, it doesn't appear those particular soffits are vented but we'll see.


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## TNTRob (Oct 18, 2010)

Ron6519 said:


> The insulation should be on the door wall, under the plywood behind the door and the ceiling. There should be no insulation in the roof rafters behind the door.
> Check out the Owens Corning site for a visual of the proper installation on the second floor.
> Ron


Why would you not insulate the rafters? This is a storage area. If it were an open attic I would agree, but it is not. Insulating this area would not cause the dew on the roof to evaporate more quickly, it would be the opposite.

1) Make sure the proper ventilation has been maintained
2) Repair the insulation as needed. The purpose of the paper on the insulation is a vapor barrier so you can use the existing insulation in place just use insulation or vapor barrier tape. If you can get to all of the seams, you should tape them as well. Most areas in the
3) Insulating any interior knee walls with R13 or R15. R19 in 2x4 walls compresses and only give you an R13 value.


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## Gary in WA (Mar 11, 2009)

"Was it done differently back in the day? The knee wall right now has absolutely zero insulation on it, but the roof rafters is where it was all insulated." ------ No, it's the same. Look again at the site I used, notice the top circled picture- just like you are describing. No floor insulation, no wall insulation, just in rafters. It all depends on where you want the thermal envelope: http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/95/950309.html

Gary


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## CoconutPete (Jan 22, 2010)

Gary: That's a good site, I'm going to read that tomorrow. For some reason I completely missed your first post when I was reading the thread on my phone earlier.

For now, just a couple of pics. The inside wall is made from 2x4's.

The rafters measure 5.5" which I finally have figured out means 2x6 in the United States :thumbup:

It's a mess in there, I think cleanup will be step 1 - I never realized how BIG that space is. Seems it would make a wonderful storage alternative to the detached garage attic.


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## CoconutPete (Jan 22, 2010)

Well it seems insulating the kneewall might not be the best in this scenario. In 2 different locations, ductwork pops up from the basement on the left side of the last picture I posted and runs across the kneewall floor, through the wall into the bedrooms. If I move the boundary to the kneewall, teh ducts are going to be in a cold zone.


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## Ron6519 (Mar 28, 2007)

CoconutPete said:


> Well it seems insulating the kneewall might not be the best in this scenario. In 2 different locations, ductwork pops up from the basement on the left side of the last picture I posted and runs across the kneewall floor, through the wall into the bedrooms. If I move the boundary to the kneewall, teh ducts are going to be in a cold zone.


The ducts should be insulated. If they're behind the knee wall they're in a cold zone already. There is nothing you can do behind the knee wall, insulation wise, that will compensate for uninsulated ductwork.
These are 2 separate but related issues.
Ron


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## bobburns (Nov 3, 2010)

"The ducts should be insulated. If they're behind the knee wall they're in a cold zone already. There is nothing you can do behind the knee wall, insulation wise, that will compensate for uninsulated ductwork.
These are 2 separate but related issues."

I think Ron hit the nail on the head, so to speak. I've done a lot of insulation work and the ducts should be insulated, and as far as the knee wall is concerned, you're SOL my friend.

________________________________________________
Bob Burns
roofing dallas


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## CoconutPete (Jan 22, 2010)

If the rafters are insulated (what's left of it anyway) and there's living space beneath the side attic, then how is it considered a "cold zone"?

If the kneewall was insulated and the rafters were not then yes I could understand that, but with no insulation in the kneewall and the rafters insulated wouldn't that move the barrier past the kneewall?

By the way, the ducts are insulated, you can see them in the bottom of the pic - looks like asbestos (fun).


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## Ron6519 (Mar 28, 2007)

CoconutPete said:


> If the rafters are insulated (what's left of it anyway) and there's living space beneath the side attic, then how is it considered a "cold zone"?
> 
> If the kneewall was insulated and the rafters were not then yes I could understand that, but with no insulation in the kneewall and the rafters insulated wouldn't that move the barrier past the kneewall?
> 
> By the way, the ducts are insulated, you can see them in the bottom of the pic - looks like asbestos (fun).


A cold zone is a zone without a heat source.
The ducts require a proper insulation, not some 40 year old version of what insulation was when energy costs were a tenth of what they are now.
The area as pictured is incorrectly insulated. If you go to any one of the insulation manufacturers, you will see a graphic of how insulation is supposed to be installed in the situation you have.
I do not understand the obtsuse and conflicted verbiage related to this subject. 
Ron


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## Michael Thomas (Jan 27, 2008)

BTW, that exposed insulation facing is a fire hazard, see:

http://paragoninspects.com/articles...zards/insulation-exposed-face-reversed-vr.pdf


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## CoconutPete (Jan 22, 2010)

Ron6519 said:


> A cold zone is a zone without a heat source.
> The ducts require a proper insulation, not some 40 year old version of what insulation was when energy costs were a tenth of what they are now.
> The area as pictured is incorrectly insulated. If you go to any one of the insulation manufacturers, you will see a graphic of how insulation is supposed to be installed in the situation you have.
> I do not understand the obtsuse and conflicted verbiage related to this subject.
> Ron


Ron:

Thanks for clarifying - I guess I was throwing "cold zone" out there when I should have been saying "thermal barrier".

Guess I'm insulating both.

EDIT: I can't believe I didn't think of this earlier ... I was just home eating lunch and it dawned on me, I went and checked to make sure. The 2 vents in the side-attic are returns. The supplies come up through the floor and only a corner of them are exposed in the side-attic. Should make it a bit easier to insulate those.


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## ianc435 (Jun 12, 2010)

TNTRob said:


> Why would you not insulate the rafters? This is a storage area. If it were an open attic I would agree, but it is not. Insulating this area would not cause the dew on the roof to evaporate more quickly, it would be the opposite.
> 
> 1) Make sure the proper ventilation has been maintained
> 2) Repair the insulation as needed. The purpose of the paper on the insulation is a vapor barrier so you can use the existing insulation in place just use insulation or vapor barrier tape. If you can get to all of the seams, you should tape them as well. Most areas in the
> 3) Insulating any interior knee walls with R13 or R15. R19 in 2x4 walls compresses and only give you an R13 value.


Remove


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## CoconutPete (Jan 22, 2010)

Well did a little digging and found this out:

1: No soffit vents, no baffles etc - this is going to be fun.
2: Old insulation is very thin, can't find any writing on it but it looks like R13.
3: Looks like a critter did some of this damage! Some of it looks like deterioration, but some of it has definitely been ripped.

Going to be a fun weekend!


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## Scuba_Dave (Jan 16, 2009)

Make sure there aren't any holes that a squirrel/chipmunk could get in
You can also get R22 instead of R19
But HD/Lowes do not carry it, I have an insulation store down the street that carries it


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## CoconutPete (Jan 22, 2010)

Scuba_Dave said:


> Make sure there aren't any holes that a squirrel/chipmunk could get in
> You can also get R22 instead of R19
> But HD/Lowes do not carry it, I have an insulation store down the street that carries it


I've already told my wife to not freak out if I start yelling and she hears a lot of noise all of a sudden :laughing:

The only thing that really worries me is that my house is a Cape Cod and I'm now faced with the gool ol' challenge of non-existant soffit vents. I checked the attic and the insulation goes all the way to the edges there, so there is no movement between the side attic and the upper attic. I can install the baffles, but there is still not going to be anywhere to pull the air from down at the bottom of the side attic.


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## Scuba_Dave (Jan 16, 2009)

I put the baffles in when I had to redo the 2nd floor
At that time I did not have any soffit vents in the front 
I installed a ridge vent w/new dormer/roof on the back
Now 6 years later I am installing the front soffit vents


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## CoconutPete (Jan 22, 2010)

Scuba_Dave said:


> I put the baffles in when I had to redo the 2nd floor
> At that time I did not have any soffit vents in the front
> I installed a ridge vent w/new dormer/roof on the back
> Now 6 years later I am installing the front soffit vents


:laughing:I thought about putting in the baffles from the bottom up to the upper attic and adding the insulation over it. I was trying to find information about whether or not that would make sense - but if you waited 6 years to put in the soffit vents then I think I can do it too haha!

I completely forgot to check if I had a ridge vent last night, I'll have to do that later tonight. I do have a gigantic exhaust fan on the side of the upper attic though, it never seals completely when the baffles close, that's gotta do something.


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## ianc435 (Jun 12, 2010)

CoconutPete said:


> Well did a little digging and found this out:
> 
> 1: No soffit vents, no baffles etc - this is going to be fun.
> 2: Old insulation is very thin, can't find any writing on it but it looks like R13.
> ...


Pete i own a cape and ran ibto the same promblem you have. I had no choice but gut ceilings an ra n closed cell spray foam. No need for soffit vents or baffles infact they block off vents and ridge vents. Got it sprayed at 5 inches which gets u a r 35 for an insulation value. While i had the ceiling open i raisef them up another 10 inches by replacing collar ties with 3/4 in plywood gussets glue and screwed. The foam has made an unbeleivable difference. I don't plan on buying more than one tank of oil this year in new england. Foam cost 3900. Plaster over sheetrock i hung cost 1300.


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## CoconutPete (Jan 22, 2010)

ianc435 said:


> Pete i own a cape and ran ibto the same promblem you have. I had no choice but gut ceilings an ra n closed cell spray foam. No need for soffit vents or baffles infact they block off vents and ridge vents. Got it sprayed at 5 inches which gets u a r 35 for an insulation value. While i had the ceiling open i raisef them up another 10 inches by replacing collar ties with 3/4 in plywood gussets glue and screwed. The foam has made an unbeleivable difference. I don't plan on buying more than one tank of oil this year in new england. Foam cost 3900. Plaster over sheetrock i hung cost 1300.


Hm - interesting. I thought about the sprayfoam but didn't pursue it due to the cost. I was actually leaning towards installing baffles and insulation and then doing something like this next summer:
http://www.dciproducts.com/html/smartvent.htm

If you dont' mind me asking - how much of an area do you estimate you had sprayfoamed? If I went that route we would be talking about probably 6 feet in height and the width of the house (idunno, maybe 35 - 40 feet) - not sure if it would make sense to go above that since the attic is insulated.

At the same time, the side attic and the top attic are the only 2 areas that are "open" i'm not sure it would be worth it to spend the money while the rest of the house is still insulated "1930 style".


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## ianc435 (Jun 12, 2010)

CoconutPete said:


> Hm - interesting. I thought about the sprayfoam but didn't pursue it due to the cost. I was actually leaning towards installing baffles and insulation and then doing something like this next summer:
> http://www.dciproducts.com/html/smartvent.htm
> 
> If you dont' mind me asking - how much of an area do you estimate you had sprayfoamed? If I went that route we would be talking about probably 6 feet in height and the width of the house (idunno, maybe 35 - 40 feet) - not sure if it would make sense to go above that since the attic is insulated.
> ...


I am not sure but let me get the contract and get back to you. It cost about 3.75 a sqft at 5 inches. It also qualifie for tax rebates 30% or 1500 whatever comes first i can try to send you pictures but it might ben. Few days. The foam is so worth it. Nosie is lowered. I will private message in a few days and try to give you some pics. Lets say mon or tues, ok. 

Your probaly have to cut thirty or so vent, the provent losing 1.5 inches on insulation. Your going to spend about 500 in venting mateeai plus labor. 

Closed cell is the way to go adds structur to your house also.

I am going to guess on area 12 ft high and thirtty five forty feet long times two.


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## CoconutPete (Jan 22, 2010)

Things determined today:

1: Someone REALLY liked wallpaper. I think I found 30 - 40 rolls in there. I also found aroudn 8 cushions and maybe 4 blankets - very weird.

2: This space is BIG - I'm looking forward to storing crap in there.

3: I'm puzzled. I pulled away the small remains of insulation and that reveals what seems to be sort of a secondary knewall - only about 1' high. What do the forum members think? Tear a hole in it? It's made of plaster. Below the floorboards or whatever you want to call them there is the same "wall".


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## ianc435 (Jun 12, 2010)

CoconutPete said:


> Things determined today:
> 
> 1: Someone REALLY liked wallpaper. I think I found 30 - 40 rolls in there. I also found aroudn 8 cushions and maybe 4 blankets - very weird.
> 
> ...


Pete one more thing i did to my house was windows. I used to get really bad ice dams on the roof above the knee wall. I couldn't even chip them off because the ice was 3 -4 inches thick. When i did the windows the damming stopped.

And the small knee wall.......maybe there is buired treasure in there


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## CoconutPete (Jan 22, 2010)

ianc435: Thanks for all the info


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## Michael Thomas (Jan 27, 2008)

Looks like a balloon framed house, the ceiling joists of the top habitable floor were sometimes installed a foot or so down from the rafter/wall junction. Also, looks like the old insulation might be Kimsul.


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## Gary in WA (Mar 11, 2009)

If you go with a closed roof system, don't worry about the soffit vents, as mentioned. 

With exhaust vents only in the attic space (creating a depressurized attic), the make-up air is being replaced by any of the following, whichever is easier: 
outside air through the roof and soffit framing (usually minimal unless very bad framing);
conditioned (inside $)air from interior wall cavities through plumbing/electrical holes;
outside/inside $ air from the insulated exterior cavities through holes (degrading the insulation and causing convective loops);
heated/cooling $ air through joints in attic duct work;
exhaust air through joints in bath, HVAC gas flues or kitchen fans;
crawl space/basement air drawn in from below traveling through exterior wall cavities (stack effect); 
or air from conditioned rooms through the ceiling joint materials below. 

The make-up air from the inside and crawl will be moisture laden to deposit on the roof framing and floor insulation. If no previous intake vents you may be fine, depends on climate and location. Ice dams need the attic air sealed and/or ventilated to remove the rising heated air. With new construction, you are required to vent the attic, as per Code, before occupancy after final inspection. The newer codes accept unvented attics.
http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation?full_view=1
http://www.familyhandyman.com/DIY-P...ency/how-to-seal-attic-air-leaks/Step-By-Step

Gary


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## CoconutPete (Jan 22, 2010)

Michael Thomas said:


> Looks like a balloon framed house, the ceiling joists of the top habitable floor were sometimes installed a foot or so down from the rafter/wall junction. Also, looks like the old insulation might be Kimsul.


Well a quick google image search of "ballon framing" certainly produces a lot of evidence to back up your idea. I still feel like I need to drill a hole in that plaster in order to satisfy my curiosity though :laughing:

Another quick google search of "Kimsul insulation" seems to reveal that it's not made w/ asbestos. I guess that's a good thing -I did wear a mask and seal the room while I removed it but I'm still happy to find that.



GBR in WA said:


> If you go with a closed roof system, don't worry about the soffit vents, as mentioned.
> Gary


Gary: Every time you post you seem to have useful links, I'm gonna try to adopt that rule of thumb some time in the future:thumbsup:

The old insulation is definitely installed with a space above it of approximately 1" between the top of it and the roof - I guess a gap is still a good thing even though there's no soffit vents?


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## ianc435 (Jun 12, 2010)

CoconutPete said:


> Well a quick google image search of "ballon framing" certainly produces a lot of evidence to back up your idea. I still feel like I need to drill a hole in that plaster in order to satisfy my curiosity though :laughing:
> 
> Another quick google search of "Kimsul insulation" seems to reveal that it's not made w/ asbestos. I guess that's a good thing -I did wear a mask and seal the room while I removed it but I'm still happy to find that.
> 
> ...


Pete here are some pics of the insulation. Did not get knee walssin the shot. Knee walls are 44 inches. Take not of ridge vent they blocked it an no venting got ten more inches out of ceiling.


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## CoconutPete (Jan 22, 2010)

Ian: I love those pictures! If the whole thing was open I would definitely consider it. Given the fact that there is only about 4' worth of exposed rafter in the side attic I'm not sure it would be a good decision to have it sprayfoamed - will need to do a little research there, it could be.

One other deciding factor is definitely going to be whether or not it's possible to put soffit vents in. I'm going to try to find out this weekend if it's even going to be possible.

I had zero problems with ice damming last year so given that fact one thing I'm considering is to just try to replace and replicate the insulation in the empty rafters and insulate the side attic floor and the kneewall/door.


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## ianc435 (Jun 12, 2010)

CoconutPete said:


> Ian: I love those pictures! If the whole thing was open I would definitely consider it. Given the fact that there is only about 4' worth of exposed rafter in the side attic I'm not sure it would be a good decision to have it sprayfoamed - will need to do a little research there, it could be.
> 
> One other deciding factor is definitely going to be whether or not it's possible to put soffit vents in. I'm going to try to find out this weekend if it's even going to be possible.
> 
> I had zero problems with ice damming last year so given that fact one thing I'm considering is to just try to replace and replicate the insulation in the empty rafters and insulate the side attic floor and the kneewall/door.


If you look at the forth pic you can see the old ceiling height. I went over kill on the gussest. 10 inch ply glued and screwed and block for strapping. I finished the room last week. The soffit vent can be installed. Buy the button vents. 3$ a piece. And pro vents 2.50 a pop. Four per bay. All in all probaly about 5 to 600 in materials. Pete i have already notice the difference. The total project cost around 6-7000 with foam. But i replugged upstair and pulled 6 cicuits and got plaster. 

I had 2x6 rafters. Seven r per inch with foam. Just ripped ceiling left wall. Filled 15 yard dumpster. You can leave strapping but make sure you screw it if its is nailed.

If you want to talk let me know.


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## Gary in WA (Mar 11, 2009)

Ian, how did you stop the air movement in the spaces at the strapping/foam so it doesn't form convective loops between the drywall/foam (2"space)? 

Did you use a sill sealer or ? for a thermal break at the strapping/drywall to transmit cold from roof sheathing? 

Gary


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## ianc435 (Jun 12, 2010)

GBR in WA said:


> Ian, how did you stop the air movement in the spaces at the strapping/foam so it doesn't form convective loops between the drywall/foam (2"space)?
> 
> Did you use a sill sealer or ? for a thermal break at the strapping/drywall to transmit cold from roof sheathing?
> 
> Gary


The foam is interior space. Closed cell foam no vents needed. No soffit vent or ridgevents needed. No more end gables either. Hot roof. The foam is an r 35. Knee walls are open to living space i am not worried about a little heat loss., i dont want a tight house. Tight houses are moldy houses. I have a pellet that heats the whole house 75+ f. So a little heat los is ok in . It has perm ratng of .87. Not barrier needed. Do people recomend double vapor barriers?


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## Gary in WA (Mar 11, 2009)

I understand a “closed or hot” roof system. When figuring your roof’s R-value don’t forget to factor in “thermal drift”, when using SPF, can lose up to 30% of the rated R-value after out-gassing, leaving just air bubbles: http://www.kwikbuildpanels.com/pages/article_facts.html
That’s why foam manufacturers list the “initial” and “aged” rating. This one drops from 6.7 to 6.4 (only a 5% drop), it depends on the type of blowing gas used: http://www.certainteed.com/resources/BIBS-HP System-CertaSpray.pdf

Also figure in the rafters are thermal bridges, R-value of a 2x6= R- 7: http://www.coloradoenergy.org/procorner/stuff/r-values.htm 
So add up the rafter thickness (1-1/2”) X quantity X length (minus) that number from the overall R-value of square footage. e.g.:16 rafters x 1-1/2” = 2’ wide rafters X length at R-7 difference from total R. 
I was only interested in how you stopped the supply air from reaching the gaps just behind the drywall on the sloped ceiling as the warmed air rises to the ridge and would be replaced with cooler air from the attic space behind the knee wall as its open all the way down. Fig. 2(a) here: http://www.aecb.net/PDFs/Impact_of_thermal_bypass.pdf 
Usually the drywall is applied directly on the rafters sometimes with a sill sealer or foam board as a thermal break. This creates chutes in only the rafter bays with fire-stops over the knee walls. In your pics the roof system appears open from the knee wall to the opposite knee wall from gable to gable. Your cavity chase with strapping (3/4”) on rafter bottoms (1-1/2”), runs up and down and side to side creating a 2” space between the foam/drywall for air movement. 
I didn’t see anything in the pic over the knee wall (air/draft stop), but maybe you added it afterward. Or maybe you spray foamed the attic rafters and the top plate of the wall below to stop air coming in? Or did you air seal the drywall with the ADA? http://www.buildingscience.com/docu...rs/air-barriers2014airtight-drywall-approach/ Just trying to see how others handle the finer details that can bug us….. 
Your cathedral ceiling R-value would work for Climates 1, 2 and 3: http://www.ornl.gov/sci/roofs+walls/insulation/fig2.html

Gary


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## ianc435 (Jun 12, 2010)

GBR in WA said:


> I understand a “closed or hot” roof system. When figuring your roof’s R-value don’t forget to factor in “thermal drift”, when using SPF, can lose up to 30% of the rated R-value after out-gassing, leaving just air bubbles: http://www.kwikbuildpanels.com/pages/article_facts.html
> That’s why foam manufacturers list the “initial” and “aged” rating. This one drops from 6.7 to 6.4 (only a 5% drop), it depends on the type of blowing gas used: http://www.certainteed.com/resources/BIBS-HP%20System-CertaSpray.pdf
> 
> Also figure in the rafters are thermal bridges, R-value of a 2x6= R- 7: http://www.coloradoenergy.org/procorner/stuff/r-values.htm
> ...


When they spray the knee walls gaps were cover up. I stuuffed pink stuff in the gaps before i hung the top ceiling. I know its not locked into the sloped drywall portion but oh well. The way the house was before i could not house any body up stairs without opening my own oil farm. The space is acctualy about 1 inch. i am not wooried about convective loops in such a small space. As far ad the r value thats all i could get out of the space allocated. I bought one tank of oil last year with a pellet stove running. Put in new windows last year ice dams disapeared and bought three ton of pellets. I am going to buy half that this year. So asfar as convective loops i realy not concerned in that minimal heat loss. Next year i plam on re roofing. I will put ice and water sheild over the whole roof on a very hot and dry summer week. In fact i am going to resheet over exsisting planking with ply. It will work. I understand about wood rafters and heat loss and its duly noted thanks for pointing that out. Wish you saw this house before.

Good job, you spent a lot of time researching this for me, thanks

How does the article apply to hot roofs besides the stud heat loss. One picture shows air flow up through soffit and out the top, ridge vent. I dont have any soffit or ridge vents.


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## CoconutPete (Jan 22, 2010)

Well, I think sprayfoam is out, first of all there's the cost aspect, but then there's also the fact that about 2' of the rafters are covered by the sloped piece of the ceiling in the 2nd floor bedrooms.

So that leaves me with a 3-part task.

1: The 4 empty rafter bays where the insulation fell apart
2: Insulate the kneewall
3: Insulate the floor in the side attic

1: Has me the most confused. There are no rafter vents connecting the ventilation space in the side attic w/ the top attic at this time - I can easily install them in the 4 bays that are empty, but would that make sense as the rest of them won't have them? In addition there's the question about what to use when replacing the insulation that fell apart in the 4 bays. The only other option is to rip it all out and start from scratch w/ rafter vents all over - that would still leave the question of what to put in the 2x6 rafter bays, but I'd rather get the kneewall and floor done first.

2: seems pretty straight forward, my only confusion is some search results say use fiberglass and some say use rigid foam
3: also seems straightforward, the biggest PITA there will probably be pulling up the floor boards, but hey are not held down w/ very many nails.


EDIT: A whole different idea just popped into my head ...... Once I'm done insulating the knee wall and the floor I could just leave the 4 bays empty or even yank out the insulation that's there since it's probably barely doing anything. Is that crazy?


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## CoconutPete (Jan 22, 2010)

Here's an update:

I think I got extremely lucky. Even though this is a Cape Cod and technically there isn't much of an overhang, there's around 4" of flat surface behind the gutters. I believe I've found the corresponding plate from the inside - some 3" or 3.5" round vents should fit right in there.

Got all the old insulation out, what a PITA - stuff crumbles if I just look at it the wrong way. Thank god for masks gloves, goggles & shop vacs. I also tore out what I believe they thought of as a radiant barrier back in 1930. Some sections had insulation and some just had air space w/ the "radiant barrier" I wonder if they just used whatever they had lying around.

Got baffles in - kind of a PITA also since the sloped section of the ceiling is north of 4 feet.

Should be in good shape by the time it gets really cold. Doing the kneewall and the floor shouldn't be too bad.


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## Michael Thomas (Jan 27, 2008)

GBR in WA said:


> ... Also figure in the rafters are thermal bridges, R-value of a 2x6= R- 7: http://www.coloradoenergy.org/procorner/stuff/r-values.htm


For those who want to get a feel for how different the results of "whole wall" efficiency calculations can be from normally published values, a good place to start is the ORNL Whole Wall R-value Calculator.


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## Gary in WA (Mar 11, 2009)

Lol, the first and last time I used that site here was almost a year ago... forgot about it.

Gary


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