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I am in the process of finishing the upstairs of my new cape cod home and have some questions about insulation. The home is located in western NY. The heated envelop will be inside of the three attic spaces. That is the area behide the knee walls and the area above the collar ties will be outside the thermal envelope. I have been researching this for about 6 months and from what I have read cellulose will give me the highest overall R value and will not lose R value due to convection currents as in fiberglass. I can easilly get the blown in cellulose behide the knee walls and into the space above the collar ties. My problem lies with the sloped part of the roof and the gable end walls. I saw the post aout costructing a jig to pack the open stud walls with the blower and am wondering how well this works? I am also wondering if this will work for the sloped part of the roof? I had an estimate done for wet spray cellulose and it worked out to about $.77/sqft at 6 in thick. If I can apply the dry blown in myself I can save considerabe dollars upfront. Is the wet spray going to give me a better overall R value? I plan on using Tu Tuf for my vapor barrier after I insulate. If I have wet cellulose blown in how long will I have to wait before I can apply the Tu Tuf. I appreciate any recomendations.
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Gee Boydman, nobody answered...
What the heck, I've been gone for a while so it's a new question to me -- I give you what I've got:
You should be able to cut little holes in the gypsum wall board and blow in the cells (dry) to the sloped rafter bays.
Shove your nozzle in to the end of the bay and blow till it's tightly packed, then back off a bit till it too is packed until the bay is full.
I don't know about R-Value for wet vs dry cells.
You shouldn't need a vapor barrier with dense packed cells and a tightly sealed drywall job.
Good luck,
Dan
*Tu tuff vapor barrier is a no no to me...rely on the dense pack to do the job along with the drywall. Seal the drywall edges and try not to penetrate the drywall with recessed electric lighting and the like...If you do penetrate, then seal as well as you can.near the stream,j
*Hi Boydman,If your project still isn't insulated here is my two cents. If you go with the wet pack take advice from a couple installers or from the manufacturer for how long to wait for it to dry.I agree with the Tu-Tuf product I am going to use it on my building project for vapor barrier.The sloped roof needs at least 1.5 inches of un-obstructed air space for ventilation from the eve to the peak ridge vent. This doesn't leave much left for "R" factor. In my installation, for the sloped part. I am using a built up thickness using 2" foam board rated at R-5 per inch. The other choice would be liquid foam applied by commercial installer, but it is hard to find a local applicator for this method.Good luck!
*bThis month's FHB addresses this topic:(and many postings elsewhere on this site do too)If you prevent the air from entering you don't need a vapor barrier: The cellulose pack is resistant to air flow, so you should not need to add the Tu-Tuf (even more so, the better you seal your drywall).bThen the only moisture you have to worry about comes from outside!It seems that we have all been drilled that vapor barriers and ventilation are always needed and always better. But FHB raises very sound points about both: bour goal is to avoid moisture buildup. If there is not a major source of internal humidity (leaking basement, poorly exhausted bathroom, roof leak, etc) then the biggest humidity source will be the outside air during the summer time. It will cause you the biggest trouble when it contacts cool surfaces (basement walls, AC ducts and in extreme case the outside surface of your drywall if it is cooled below the dew point, by your AC!). I have been studying the humidity in my house through the seasons and found that I simply can not create enough moisture (Relative Humidity), in my closed bathroom with the shower going full hot, in January to match that found in the outside air in Michigan in July. My (unscientific) study filled me with doubt about venting. FHB makes sense. The current building code may require venting when it is not appropriate. The ruling bodies are addressing this, according to this month's article.
*Clarification required, NormFHB said no such thing. A self serving contributor made those statements. DO NOT attempt to give credibility to something you don't understand by linking it with a fine magazine like FHB. Get your nose out into the sunlight, that's not coffee you're smelling.Gabe
*ouchIf FHB printed the article (it was featured on the cover) I thought they agreed with its content.The article stated quite clearly that the ruling bodies where struggling with this difficult issue (venting) BECAUSE it was so controversial.(I'll re-read it tonight to make sure I did not mis-understand anything).I did, however, touch on several topics in my previous posting, so I may have mis-understood your comment, Gabe. Venting and vapor control. Maybe opinions and experiences are so different because each house, climate and even wind direction make such a difference (what worked well here didn't work well there) and the variables would be a bitch to try and set up universal Codes for.The anonymity of, and ease of access to, the web makes it very hard to know who truly had a matching experience that we should take their advice or even if it was in the same part of the country, not to mention whether they really know what they are talking about. :-)The huge amount of postings on this web site attest to its value to all of us, and it is fascinating for me to see how often advice conflicts, from one reply to another!
*All publications carry a disclaimer to ensure that everyone understands that the information contained in their respective magazines is not always their views or carry any kind of endorsement from the publishers.Your absolutely right when you say that it is impossible to have a universal code to cover every aspect of construction.Just as this discussion board is international so are the comments.Having sayed that, you will not be able to find a baord anywhere else on the internet that comes close to the quality of this one. But, the advise is regional in many cases. The only exception is the advise from FreddyL who thinks he is universally qualified in dishing out advise, without facts.One fact stands out amongst all others, and that is, there is no simple solution to everyones heating and cooling problems.Every component must be considered. The regional climates, the type of construction, the experience of the builders, the materials used, the desired effects of the heating and cooling, the lifestyle of the occupants, the cost of various fuels in that location, the time of year for construction and the relative humidity, the roofing materials, the finish room materials, even the paint will have a bearing on the formula.So how some genius can simply state, dense pack cel, the walls and ceiling, making sure that you don't vent the attic and don't forget not to install the poly vapor barrier and you will be able to heat your house in Alaska or cool your house in Alabama for $40.00 bucks a year, defies logic and is totally irresponsible.This is the same genius that does have a huge disclaimer at the beginning of his home page.Gabe
*But the article FHB did ob fiberglass and poly was 100% accurate and correct, right?-Rob
*Gabe,Why don't you see if you can get FHB to publish some of your personally scribed wisdom?Steve
*Steve,They already do on Breaktime. Maybe next year I'll prepare a story for FHB. Right now, fightin bad guys and building monuments.Gabe
*Rob,No article longer than 50 words is always 100% accurate and correct. The longer the article the lower the accuracy score.Gabe
*As a somewhat lapsed environmentalist, I have always been partial to cels. However, I remember reading a couple of years ago about some tests done on cels that had been in walls for up to fifteen years with the result that very little fire resistance remained. The speculation of the article was that fire resistance could be compromised severely within the first five years. Of course, the author did admit that he couldn't be sure just how well the cels were treated before installation. What is the current thinking on long term fire resistance with cels - both blown in and wet?
*A comment and a question...The whole question of vapor barriers seems to depend on where you live...here in Fairbanks Alaska the interior/exterior temperature difference is so large that relative humidity is greatly increased, and you are asking for trouble if you don't use a vapor barrier. That said, I too have questions about cellulose...I haven't installed it before and am wondering how one goes about doing so if no drywall etc are in place- on several jobs I worked on in MN years ago I seem to remember that the insulators installed a sort of mesh over the studs and blew the stuff in, can't remember if that was fiberglass or cellulose. Another problem is that I will be working in a relatively cold place, woodstove will be going but no insulation and zero degrees outside already...Any advice?Olav Ormseth
*Two comments: First, I would check with the local Fire Marshall about cellulose before using it. There has been some question in the past about the fire retardant retaining its' effectiveness after some years. With respect to insulating in the winter: Why not? Of course personally I would probably either use foam or fibreglass for walls in a sub-arctic climate like Fairbanks. But houses get finished well into the winter all across the north country; just how much frost bite do you want to risk to do the job?By the way Olaf how are things coming on the house? Just how level and flat did you get it?:<)
*Fred-You remembered! I got the house very nice and level, thanks...of course, it being post-and-pad it has probably changed a little now...My main question with the cold is how it affects wet installation, I really don't know much about cellulose. Why would fiberglass be better? I have ruled out foam due to expense, toxicity of the iso, and the fact that temp changes/settling seem to open up a lot of gaps where the foam meets the framing (at least, this seems to have occurred in the old part of the cabin). My original intention was to use fiberglass, then I saw alot of stuff on cellulose and thought it might be worth a try.-Olav
*Hi Olav,I think FG would not be the thing for a really cold climate. The colder it is the more convective currents come into play in heat loss with Fiberglass, as it allows air movement through itself. I forget the exact point where it comes into play in attics, but I think it's around 10 degrees ambient temp adjacent to the FG. Whether it's a factor in walls is less certain, but I am a convert to cells after a years worth of heated debate on this board.I would dry blow it to high density (about 3-4 lbs.cu/ft).The air-sealing benefit is the best thing about cells in my book.The fire-retardant issue is a "smokescreen" in my book. Cells cavities burn slower than FG filled cavities. If your house catches fire you've screwed the pooch no matter what, but you buy a little more time to get out if the wall is burning slowly rather than going up like chimney.Steve
*On the topic of cells losing fire-retardant over time:I took out some old cellouse from my house (insulated some years ago) and tried to burn it. Flat out, it would not support any flame. The most I could get it to do was slowly turn to ash under constantly added flame (torch), but it would not support its own flame without the torch.In the auto industry, that is considered a 'safe' type of material (almost anything will burn if heated enough).There are tables showing just how fast an unsupported flame may propogate thru a material to meet FMVSS auto flamability standards. My cellulouse rates pretty highly, per that measure (zero propogation by itself). Maybe some cellulouse was made poorly, or maybe some houses burned down anyway. But after reading the industry information (and my own test), I feel good about it for my house.
*I Really don't want to get into the controversy about what type insulation to use under what circumstance. In fact my preference is to use different insulating materials in different parts of the structure.Much of the insulating materials controversy on this board comes from the thought that what works in one area works throughout the continent. So folks argue passionately for their solution without taking into consideration climate and life style differences. What I would do in urban CO is related to but different from what I would do in bush AK. For Alaska I recommend contacting the UAF Cooperative Extension Service for their "Insulation Fact Sheet". This is a product of a lot of research about Arctic and Sub-Arctic construction. They also have lots of other material that you might find useful.Re: Cellulose and fire. The early cellulose had a real problem in this area. I understand now if it is rated "Class A" it should be ok. So, it just makes good sense to check with the Fire Marshall for the latest word on flamability and whether it is allowed. Since you are doing it yourself, knowing whether cellulose is allowed and any required installation considerations makes good sense both from a safety and an insurability point of view.The foam I was referring to is sheet foam, not the spray in you probably have in your place.
*Olav,My guess is that you probably had a rigid polyurethane foam installed in your cabin in the past. The newer foams (lightweight and flexible) do not offgass, nor do they settle, crack or shrink. Maybe you should contact an Icynene contractor in your area and ask for a sample. Just a thought - Good luck with your project.Sincerely,Sue V.
*Wow! It's been months since I've visited this site, and now I return to read this hopefully interesting post and find that Gabe is still personally attacking people. Does he even know that he is doing it? Gabe, if you disagree with someone, say so, and then support/argue your position. You don't need to resort to demeaning remarks about the individual. There is a proper way of doing it.For example: Gabe, I disagree with what you said regarding the article mentioned above that was published in FHB. When people talk about an article they read in a magazine, that's how they refer to it: "an article I read in FHB", or as the above poster wrote: "This month's FHB addresses this topic". That is exactly correct, as they like most people are referring to the magazine. And the magazine does address it. He didn't claim that the editors or staff of FHB addressed it or supported it. You said "FHB said no such thing. A self serving contributor made those statements." Well, FHB the magazine did say such thing. It was an article, not a letter to the editor. You claim it was made by a "self serving contributor". Well, what is FHB if not a compilation of articles from contributors.Gabe, note from my example above how I disagreed with you, presented my position, and let my argument speak for itself. I never resorted to attacking you personally. I didn't use your technique as you did above, and say that a "self serving" "genius" like you, who "doesn't know what he is talking about","dishes out advise, without facts", "is totally irresponsible" and "should get your nose out into the sunlight". I would never say that, and you shouldn't either!
*Just in case your looking for a reply from Gabe, he hasn't posted since September 22. Doesn't mean he won't reply, but I wouldn't hold my breath.Rich Beckman
*olav,I agree with Steve....near the stream,j
*Norm, Fred B et al. As the only insulation regulated by the federal government, cellulose has acquired an undeserved reputation. In 1990 Dr. David Yarbrough, Chairman Department of chemical engineering at Tennessee Technological University, performed what is considered to be the best work to date on borate fire retardant permancy.Interest in the sublimation (change from solid to vapor) of boric acid started as far back as 1937. Dr. Yarbrough's laboratory study of boric acid transport was supplemented by computer modeling to show that it would take hundreds of years of 70 degree centigrade(DC) (158 degrees F) and 100% RH to lose a detectable amount of boric acid. /the loss rate goes up with temperature. Yarbrough concluded that tempoeratures above 158 DF in an attic space woould be rare. He also founbd that at 90 DC (194 DF) the boric acid loss rate is signirficant if the humidity is high (above 50%).What about loss of bvoric acid due to vibration? "...significant boric acid redistribution due to vibration did not occur...Vibration at 60 hertz [cycles] for 672 hours would be equivalent to more than 672 years of in-situ exposure."Suncoast Insulation,Tampa, Florida, a manufacturer of cellulose insulation,has funded several studies of aged cellulose insulation. It's 1993 study conducted by and independent testing lab using gas -fired radiant panels specified by ASTM C-739 and the Consumer Products Safety Commission Interum Safety Standard 16 CFR part 1209.All tested samples easily passed Once again cellulose known to conform to required federal and industry stasndards was found to comply with these standards as longas 14 years after installation.Some of my post on this subject are in the archives. Hope this helps. By the bye. Not all research papers on the safety of fiberglass insulation have not been peer reviewed.GeneL.
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I am in the process of finishing the upstairs of my new cape cod home and have some questions about insulation. The home is located in western NY. The heated envelop will be inside of the three attic spaces. That is the area behide the knee walls and the area above the collar ties will be outside the thermal envelope. I have been researching this for about 6 months and from what I have read cellulose will give me the highest overall R value and will not lose R value due to convection currents as in fiberglass. I can easilly get the blown in cellulose behide the knee walls and into the space above the collar ties. My problem lies with the sloped part of the roof and the gable end walls. I saw the post aout costructing a jig to pack the open stud walls with the blower and am wondering how well this works? I am also wondering if this will work for the sloped part of the roof? I had an estimate done for wet spray cellulose and it worked out to about $.77/sqft at 6 in thick. If I can apply the dry blown in myself I can save considerabe dollars upfront. Is the wet spray going to give me a better overall R value? I plan on using Tu Tuf for my vapor barrier after I insulate. If I have wet cellulose blown in how long will I have to wait before I can apply the Tu Tuf. I appreciate any recomendations.