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I am remodeling a 1920 Colonial Craftsman house in Cleveland Ohio.
I got the shinglevent II at the ridge and continuous vents at soffits.
The front of the gable has the old 2×6 rafters. The back of the gable is new and has 2×8 rafters.
The insulation has just now been installed. After it was installed, the roof snow began melting, from the ridge down.
The ceiling insulation just below the rafters is R-19, the largest my supplier said was available.
I saw Norm add rigid insulation at this point, over the insulation, inside the bottom of the rafters.
Thoughts on this, please…
Replies
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Sorry about that...I do have air chambers.
Also, at the points where the inside of ridge, and each end of the spreaders form a triangle; and adding that the spreaders are about 5' long; is R-15 just above the R-19.
I have noted that heat is not coming out the ridge, and melting that way. I think the heat is stopping at the 5' spreaders ceiling, and maybe going to the sides and leaking through where the rafter, spreader intersect.
Thanks for your help.
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ADDITIONAL INFORMATION:
If I have R-34 (R-15 plus R-19) at the point of spreaders/ceiling...
And then only R-19 at sloped points...
And I am guessing here...
Then at that intersection of R-34 and R-19, which is where the spreaders meet the sloped roof is where the heat from the steam radiator is leaking...
And cold air is coming in at the ridge, and down onto that warm air going up at that intersection...
And rising...and I cant figger what the soffit vents are doing...
But just let me say...I went to great expense and hard labor to get this fancy new cold roof that no one else in the neighborhood has and I am the only one with the sound of springtime rain while it is minus-something wind chill and very , very quiet...
And I sifted through a lot of arguements with the commentators in this arena, notwithstanding the censor period, and the thereafter so-called problems with programming...
Well, let me say it this way, I am counting on help here!
Please?
*Thank you for your response , Joseph.The steam radiator does not leak. This system employs a small vent to allow air out when steam comes and air in when steam goes to water.The location is the third floor, which might be called a finished attic. The radiator is located just inside of the top of the stairwell, which is about 6' x 6'. The height of the spreaders/ceiling is 9'.I want to avoid more insulation, if I can. I am wondering if I can install some 30lb felt paper on the slopes and direct the heat to the spreader/ceiling area.There is no condensation. The rain I was talking about was the snow melting off the roof.Thanks again for your help.
*From "This Old House Heating, Ventilation, and Air Conditioning- A Guide to the Invisible Comforts of Your Home" by Richard Trethewey with Don Best ISBN 0-316-85272:Page 109: ..."How They Work Hydronic systems are characterized by a central boiler or water heater, which uses gas, oil, electricity, propane, wood, or coal to heat water. The resulting hot water or steam is then distributed through a pipe to some sort of radiator, which releases heat into the room. The heating cycle is completed when the water or steam has given up its heat in the radiator and returns to the boiler. Up until the mid-1930's, steam boilers were the popular choice for residential heating, employing the same technology--on a pint-size basis--that powered America's locomotives and factories. The best of those early-day steam systems demonstrated a remarkable understanding of physics and very clever engineering. The worked well without pumps and sophisticated controls, just as long as there was someone around to periodically shovel in the coal and keep water in the boiler. As shown in the drawing on page 000, steam generated in the boiler would rise through the pipes under its own pressure and surge into the home's radiators. An air vent on each radiator remained open, which allowed the steam to enter, until the temperature rose high enough to close the vent automatically. As the steam inside the radiator cooled and condensed, the water collecting inside would either trickle back down the same pipe through which the steam had come (a one-pipe system) or drain down through a second pipe (a two-pipe system). In either case, the pipes had to be gently pitched so that gravity could return the water to the boiler."...Hope this helps.
*Do you have side attics - as typified by sloped ceilings over part of the second floor rooms?Is the house balloned framed?Also, is the insulation all fibreglass? Unless it fits perfectly and is in an enclosed cavity - not open to the attic - you're not achieving anything near R19. How long has it been in? Go see if there are any dirty spots yet where air is blowing out of the house.
*It seems, at present, that my questions in this matter can best be answered at http://www.weatherization.com.Thanks for the help.
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Where is the house at? I can drive by and have a look at it. I too am in Cleveland. Although it would seem to me that it is warm air escaping from the attic space causing the snow to melt at the ridge (warm air rises and escapes here first). Is it melting consistently along the rige and is it a large scale melting or just near the ridge? could this also be caused by the roof itself warming and that heat rising throug the ventilated area to the ridge. I know we have not had much snow here yet so I wouldn't think the roof was completely blanketed therefore exposing areas to the rather strong sunshine we've had.
Let me know,
Pete Draganic
Central Diversified Contracting
216-271-6458
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Thanks Pete !
It was very nice of you to offer your assistance.
I enjoyed our talk this morning.
*Thanks for your comments , Joe.I like it that you feel comfortable speaking out what might be on your mind.I have a steam heating system. And yes, there are a lot of "new" things to consider with this type system.That site, http://www.weatherization.com shows that even if I did an excellent job with the insulation, there are forces beyond the eye at work.Go there and look for yourself, please.I would really value your informed opinion.Hope this helps.
*Thanks Bill.This old house was balloon-framed. I have been adding blocking, removing walls, new roof, this and that, in effort to change the dynamics of this structure to platform framing.The fiberglass is new.There better not be any "dirty spots", and most likely are not.From what I understand , from looking at the http://www.weatherization.com site, is that the hot air is being forced out the spaces between the rafters and the insulation because of the basement leaks (cat accesses through the windows).There is an awful lot to learn and do to make a house tight as a frog's butt.Thanks for your help.
*You state "From what I understand , from looking at the http://www.weatherization.com site, is that the hot air is being forced out the spaces between the rafters and the insulation because of the basement leaks (cat accesses through the windows)." I don't believe that is what Fred's site intends to convey. The hot air is blowing out between the rafters and insulation because there are holes and hot air rises (usually). That creates a negative pressure which sucks exterior air into the building. For a variety of reasons, it isn't practical to stop every hole below the neutral pressure plane - plug one and the air will find another to come in - because there are so many more opportunities low in the building.Could you blow a layer of cellulose over the fibreglass to get it to "fit" and not blow so much air?
*Bill, The insulation was installed so that the insulation fit between the rafters. I am guessing that the fancy Shingle-Vent II that I installed is sucking some heat out, but the insulation really doesnt have spaces to speak of.Where I am at with this remodel, is that point where I am just keeping the weather out on the second floor back half of the house, and just recently did the new roof, the cold roof.My apprehension, in this brand-new modes of thought...to wit: cold roof, insulation, vapor barriors, vents, and so on......is at the third floor ceiling. My insulation "envelope" will be at all outide walls , to the roof and up from there at the roof, and across the spreaders. Across the spreaders is the R-19 that is used in the rafters, but also with R-15 as well to help get a little more "distance" between the open ridge and the ceiling/room underneath.I dont want to put the drywall up if I need to put a different vapor barrior or something.Can you help?
*Still trying to figure out the geometry of you house. Reading your last post it dawned on me that your "spreaders" are what some folk call collar ties - I had thought you were referring to solid bridging between joists. So a portion of the top floor ceiling is sloped? And are there side attics or does the top floor extend all the way to the exterior walls below?Was also wondering if in "converting" from balloon frame to platform frame you plugged the ends of the second and third floor joist bays which are open into the walls? I removed siding and sheathing boards on my house at that elevation to plug the ends. It sure is an effective route for air warmed against the ceiling to be cooled off against the exterior wall sheathing.
*Sorry about that Bill.I do call them collar ties. I dont know why I was calling them spreaders.The solid bridging between the joists I call blocking. I hope that is correct...Regarding the third floor ceiling, the roof used to be gable, with each angle to about 45 degrees. The back of the house was extended about ten feet out, so the angle is different, I forget what it is.Because the air chambers go from the soffit to the ridge, and in an effort to do other things about which I now forget, I put the insulation in the joists and rafters, all the way to the soffit.I think I was trying to create a large dead-air space to help keep the room underneath a little warmer.Everywhere that needs a block, gets a block glued and nailed so as to prevent lateral movement, first, and then to gain whatever other advantages it might achieve.On the old walls, I first caulk the space between the old 1x8 sheathing. Later on, if possible, the old tar paper can be replaced. But for now it wont matter.Then, I fill it with the right size insulation. Wire. And put 3/4" sanded one side plywood and 1/2" drywall.In what I have done, there are no leaks.Thanks for asking.Hope this helps.
*Hi Alan,I'll jump in on this one, just for fun.If I understand you correctly, you haven't yet put the drywall on the ceilings (the collar tie area) or on the sloping bit, or on the kneewalls. Is that correct? Do you have knee walls, or as bill asks, or are the walls below the collar ties (the rafters) at a slope all the way down to the floor of the attic?Anyway, if you haven't yet drywalled, then I suspect that is a large part of the problem. The FG, even tightly fit, will allow large amounts of heated air through and around it. It'll congregate at the top of your "cold" roof, exiting through ridgevent, but not before heating the roof enough to melt your snow.That's my best guess. Without a continuous air barrier, the FG is nothing more than a giant air filter with little-to-no insulation value. Even with the air barrier, if the back side of it is exposed to a source of outside air, the R-value also drops dramatically. It is my understanding that the only way FG performs well is in a tightly closed 6-sided box.Mr. Lugano has pointed out that the only time he has seen a vented roof with FG insulation work well is when the vent channel is completely sealed off from the FG. One way to accomplish that is to run 2x2 nailers on both sides of the rafters up tight to the roof deck, then span the 2x2's with ridgid foam or plywood and seal the joints. Then fill the remaining space with FG. This is an expensive way to accomplish what could readily be solved by simply foregoing the vents and denspacking the rafter bays with cellulose instead.Also, am I reading correctly that you are putting 3/4 inch plywood on the interior wall surface, and then covering that with drywall?In sincere help mode,Steve ZerbyMeetinghouse Restoration
*Thanks Steve, thats pretty much whats going on here.I didnt know that fiberglass insulation has so many problems.The roof does melt the snow surprisingly evenly.
*What is the 3/4 sanded one side plywood for? And why sanded when it will be covered with DW? I have been placing 1/2" CDX or OSB on the underside of my rafters, but this is due to the fact that uniform size DW sheets and uneven joist spacing don't get along. Actually, the sheets will make good shear panels and stressed skins to reduce deflection.-Rob
*Same purpose here, so as to make "torsion box"; preventing racking and twisting. Deflection of any kind.Nail it where it lies is the codeword for today.Make it stay !When I first came back home, to Cleveland, from San Diego, a couple of years ago now, I had to re-learn building. The uniform building code is west of The Mississippi, and countless others to the east.Even here, while it may seem that CABO or BOCA apply, there is a regional code that the inspectors use.Anyhow, to make a long story short, this house wiggled. I know it sounds ridiculous. I could not believe it myself. I tested by staying away from the five pots of esspresso I was drinking in those days and sure enough, it wiggled.And my project here began with staying the members in place and redistributing the loads.Now, added to the problems of learning the codes, suppliers in this area are not the same as they are in San Diego. Here, it is customary to first abuse newcomers by things like qualifying as a contractor, then a contractor who is worthy of their supply, then the clerk who has his own agenda when getting me a copper fitting or something.So, when it came time for plywood, the common denominator was the 3/4" ply. This was about $20 a sheet and 1/2" was $18, after all the quotes were in. (I got quotes of $40 a sheet for the 3/4").I have used over 120 sheets of that 3/4", for the floors, roof and walls. I have to say that I like having only one size ply (sanded is used for convenience of handling, primarily) , as it can be relied upon to act one way in each of the applications. What I mean by that is the feel of 3/4" on the roof, and the feel of making the roof, is better because of the quality of the material.Since I am a one-man show over here, with this demanding job, I did not want to have separate storage areas for the different plys. Space is very limited here. For me, the 3/4" sanded-one-side is just easier to use in this application.Notwithstanding all of that, WOW !, it does a good job.Hope this helps.
*Hi again alan,The picture is coming into focus now.Sounds like the place ought to be bomb-proof by the time you are done! As to your insulation problems, since you are already invested in the FG and the ceiling is still open, I would suggest trying the air-tight vent channels. Either that or bail on the vents altogether, sell the FG to a "friend" or use it elswhere for sound insulation or something, and blow densepack Cells. Good luck to you on your new location. I know how tough it is to re-establich all the ties that building relies upon.Steve Zerby
*Steve, Thanks for responding. As is indicated in one of the above posts, I have the air chambers above the insulation.I am hoping most of my problems will end with the drywall going up.I am just wondering if I should put 30lb felt over the entire ceiling so to "trap" the heat a little more.What do you think?
*Hi Alan,I don't think the felt would make any difference. What you really need to do is make sure any penetrations through the ceiling (ie: plumbing vents, wiring holes, intersecting partition walls, etc) are sealed with foam. You want as leak-proof of a cap on the house as possible. A continuous cover of taped and painted drywall will stop the rest.The fact that the vent channels are above the FG will not stop the loss of R-Value. The back side of the FG is still exposed to the wash of exterior air that will draw the heat right out of it. What will make the FG effective is if you completely enclose it in an airtight box. In order to do that you would have to detail the vent channels something along the lines of the suggestion in my earlier post.Steve
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Dear Allan
Apologies for my jumping in so late on this thread, but it did allow me to carefully read all the other posts. Notwithstanding the various terminology confusions, I think the one thing that the others have missed is that you simply don't have enough R value on the slope part of your roof. R19 is NOT ENOUGH!!! In Canada the minimum code requirement for a slope/cathedral roof is R30, for the flat part of your roof, above the collar ties it would be minimum R40! In Ontario you would be allowed to dense pack the slope part of your roof (no ventilation required), but would have to ventilate the flat part assuming that there was an air chamber above it.The very least you should do is to beef up the insulation on the slope. If I were you I would install Expanded Polystyrene (R5/") onto the rafters.Use the shiplap configuration,install it tightly,and run a bead of acoustical sealant in all joints; 2" will add R10 and the assembly will now =R29 which, with the break in thermal bridging and the addition of drywall will be at least R30, not withstanding Steves observations of reduced R value due to cold air washing one face of the F/G. (A cheap way to alleviate that would be to remove the F/g and install plastic/styro vent shutes all the way from the soffitt to above the flat ceiling insul. this might reduce the effect of the venting air washing over the F/g.) Be aware however, that applying drywall over 2" of foam presents dificulties, longer than common drywall screws must be used- 3 1/2" are manufactured but not easy to find, or you can strap/fur and then rock. Fire code mandates that foam board must be covered with a firerated product.
It sounds like you have a big house, I can't help wondering why you chose to insulate this way. Unless you need to use the attic as living or storage space you might have been better off piling insulation onto the joists and leaving the rafter bays open. Otherwise, you should probably heat the attic, but not before you double the R value of those slopes.
Thermally yours
Patrick
*Continuing this same discussion. I think the reason you melted the snow was air infiltration since you do not have the ceilings done yet. This is the primary loss of heat in older homes. I agree with Pat that our insulation standards are not stringent enough. Now is the time to add more insulation. I recommend R-30 at least. Please what ever you do keep the ventalation in the attic present to prevent moisture build up. Also put a vapor barrier on the interior of the insulation. Not tarpaper but poly which will be held in place with the sheet rock. This will add immeasurably to your quality of work. Good luck. Savoy29
*I have had very bad experiances with ridge vent. I DO not recomend them. I used them when they first came out and have had to scoop snow drifts out of attics by the garbage sack full multiple times. I finaly went back and tore them off and replaced them with can vents, The manufacturer would not stand behind them. DR
*Alan,I am in the process of finishing up a similar project here in Vermont. The house is a 1 1/2 story home, with 2x6 rafters. The upstairs has limited headroom, so I was not interested in encroaching into the space with additional framing or insulation. What I did was use 2 layers of 2" Celotex rigid insulation. This has an R value of 14.4 per 2". Each board is slightly less than 2" so I am left with an airspace that is nearly 2", which adds a total of R-2. This gives me an R-30 (not counting the reduction for the studs). Above the flat ceiling I used R-38 batts, as there was just enough room between the ceiling and ridge. We have just finished sheetrocking and taping. The first snowfall was this past weekend, and the roof seems to be holding all the snow, with no signs of melting.You may try to add a layer of 1" or 2" of rigid insulation on the inside of the rafters, this will add a lot of R-value because the insulation will be inside of the rafters, which are conductors through the roof. The rigid insulation MUST be covered with sheetrock to protect it from fire. This is a more expensive solution, but I know it works. The only problem will be you have to use longer sheetrock screws to go through the insulation and into the rafters.Good luck
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Thanks Christopher, thats my story here too.
I didnt want to put up drywall until I knew that the roof was going to work properly. I think that the rigid insulation is the way to go. I was hoping that I could just slap something up there, thus, the tar paper thought.
Since I first wrote this, I have been watching this roof. And since the first writing, we have not had the heat up as high as it was when cold first fell upon us.
I am going to pull down some of the insulation over the collar ties to see if there is snow or if it is wet. I hope not, of course. But I dont think there will be, mostly because of that free tape that AirVent sends called "Blowing away the myths".
Since my first writing, I have not noticed too much melting. I think that if I were to put 5/8" drywall instead of 1/2" that I would be okay.
Just to be sure, however, I think I will put that rigid 2".
Thanks to everyone for your help. This cold roof thing was a difficult endeavor. I would not have known about it without this message board and those who share here.
*My current research brought me back to the certainteed.com/ attic-section two place which says that my attic is the same as a cathedral ceiling.I know that I need more insulation. Of course, I would like to avoid that. I would also like to avoid changing over to cellulose (money is tight).But, it has been suggested that I need a vapor barrier, such as visqueen over the craft paper, and then another source says that no visqueen and just painted drywall is enough.MORE HELP PLEASE !I have icicles that rain, like a chinese water torture, even though it is snowing and cold. Should I put the visqueen. And do you think the rigid insulation over the craft paper is absolutely needed?Thanks.
*CURRENT STATUS:My problems seem to stem from as follows...The work is in progress, floors open, no attic ceiling. This seems to be a "stack effect".The attic ceiling is a cathedral and or vaulted ceiling. This ceiling requires R38 or R40.I am still investigating this "radiant barrier" thing, with its rigid insulation over the ply on the roof I thought I just finished.So, if I understand so far, not only do you have to be able to shake a house, you also have to be able to stick a special fan in the front door and be able to try and blow up the house like a balloon.Well, notwithstanding my workload, because I am determined to do this precise, this old house only had 2x6 rafters. I put 2x8 in the back, but to put 2x12 just to accomodate the insulation means that the walls have to be beefed up.Any thoughts ?
*One more thing...My concern is that if I close up the house, insulate the ceiling to R40, etc...1) I will still have stack effect because of stairs from basement to third floor, no, the second floor if we keep the third floor door closed. So maybe a basement door is needed?2) How do I get fresh air, or proper ventilation. This old house has steam heating. I cant even figure what I might be doing with the pressure thing. (The ventilation.com site is having trouble with the site. It wont open that section). I will have two bath fans, one hood fan, and I was thinking of a basement fan with a humidstat. But where is all the intake air going to come from?Thanks again. Especially for not indicating that maybe my pain might end if I just got out of the business.
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Allan
You sound like a guy who is tearing his hair. Please don't take what I am about to say as snide, condescending, arrogant, or mean spirited. I have followed this thread from the beginning and I can't help observing that I don't think you have a real grasp of what you need to do and what is conflicting info. I presume that you read this board often enough to have accumulated a lot of new information, but I sense that you are misunderstanding how some/all of it works in your particular case. The concept of a cold roof, for example, is not new, it is undoubtedly what all those neighbours you refer to have. . . top floor ceiling covered with some sort of insul, with or without vents and a vapourbarrier. What you are doing by insulating the cavities of your rafters and venting from soffitt to ridge is also a type of cold roof but because of the depth of your rafters and the desire to provide a vent space, your insulating area using F/g is limited, therefore you have heat loss and raining icicles. You don't need to redo the outside of your roof, you need to add insul. There's no need to beef up your roof rafters, as stated several times before on this thread by myself & others 2" of Extruded Styro, or foil faced Polyiso, will give you the R value you need and caulked or taped will actually preclude the vapour barrier you talk of. Painted 1/2" d/wall will provide an air vapour diffuser which you really won't need with the RFIB but this material must be covered to meet with firecode.
Too much information can cause anyone confusion at times and, pardon me again for being blunt but I think you need to stop asking questions and start beefing up that insul.
A basement door is always a good idea, and if you have a knee wall configuration, make sure that the area on the cold side is well insulated and sealed on the warm side of the floor. Unless you've managed to seal the rest of the house tight as a drum there will likely be plenty of air leaking in, if your windows start steaming up & dripping condensation, open one. . . it's that easy!
Turn off the wheels man. . .buy some RFIB and stick it on.
With only good intentions
Patrick
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Okay Patrick.
Good advice.
It does sound like insulation is key.
By the way, every house in this neighborhood has icicles. I believe the cold roof design is the way to prevent that.
If every hair of my head needs pulling to get this cold roof to where it will function correctly, so be it.
Hopefully, this crazy thread will save someone else from this very difficult operation.
Frankly, I thought I was doing good by just becoming aware of this cold roof design. But it is not just one design. There are many opinions about every detail, begining with some dont think the cold roof works at all.
Your advice now, Patrick, is welcomed. But please understand the road I took to be here.
Thanks.
*Hi Alan,It's a brave new world, isn't it? All these people flying at you from all directions with contradictory advice and opinions. I used to think if you just got a book and read it you would know the the proper way to do something. One thing the Internet has forced me to do is to consider the source much more critically and to look for independent confirmation of everything. It has also exposed me to many more ideas and to critical evaluations of what have long been considered the "correct" ways of doing things.I've built plenty of the classic drywall/poly/FG/vent channel/roof deck structures, and not thought twice about it. Then I started reading in the mainstream press and the trade journals about such structures failing to prevent moisture damage. I haven't been in the business long enough to personally see my own structures fail. I have seen symptoms of their failures, though--I've built R-38 FG roofs that fail to prevent ice dams on one part of a house, but not on other parts of the same house. I suspect it's only a matter of time till some of the roofs systems I've built begin to rot from condensation. Now I'm on a quest to really understand how the whole system works. It's confusing to say the least, but interesting.One thing about your last series of posts. The stack effect. If you put a damper at the top of the chimney you stop the warm air from escaping, and no more air needs to enter the system to replace its volume. My understanding of it is that if you close the top of your house, even if the volume within is open from the top floor to the cellar, you will have defeated the stack effect. I'm no psysicist, but that is my understanding of it right now.As to the amount of insulation required, it really depends on what the real-world R-values of the system you chose wind up being. Gene has posted in the past about testing that shows that whole-wall r-values are often much less then the R-values of the insulating materials themselves.Many here argue that FG when exposed to exterior air is a very poor insulator. I tend to believe this, but would like to see empirical data on it myself. I don't think the staple-up Styromfoam vent channels would isolate the FG from the exterior air very effectively, as they are not really designed to create an airtight channel.Fred has said that he has great success at stopping roofmelt and ice damming with as little as R-20 of densepacked cellulose.I would think that if you can create a relatively airtight chamber for the FG, it would not really be necassary to install 12 inches of it.And air sealing the top of the thermal envelope will make a big differnce, I believe. The trick is doing all this cheaply. From scratch you can do it pretty cheaply and within the space of a 2x8 with denspacked cellulose. Now that you have the monetary and psychological investment in the FG--and I understand completely as I'm in the same boat with the areas of my house that I've already completed--I would still try and isolate the FG from the exterior air passing through your vent channel, if nothing else. That and effective air-sealing of top of the Thermal envelope would go a long way, I think.Good luck in your search for answers.Steve
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Alan
Further to Steve's advice on the vent shutes, which I prescribed in an earlier post as a possible 'cheap fix', I have insulated several Cathedral ceilings with a combo of f/g batts and strips of Glasclad (compressed f/g with one 'tyvek' type facer, R4.5/", in a 4x8 sheet manufactured by the Pink Panther folks as an exterior board insul.)cut to fit snugly in the rafter cavity laid up against 1x2 strapping which is nailed to the upper inner face of each rafter to create a vent shute that has some insulating qualities, and the ability to shed condensation back to the soffitt if the paper side is placed up. It's a bit labour intensive but it does a great job.
Patrick
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I am remodeling a 1920 Colonial Craftsman house in Cleveland Ohio.
I got the shinglevent II at the ridge and continuous vents at soffits.
The front of the gable has the old 2x6 rafters. The back of the gable is new and has 2x8 rafters.
The insulation has just now been installed. After it was installed, the roof snow began melting, from the ridge down.
The ceiling insulation just below the rafters is R-19, the largest my supplier said was available.
I saw Norm add rigid insulation at this point, over the insulation, inside the bottom of the rafters.
Thoughts on this, please...