Ok now I understand, I almost did that on my house, I did not know any better at the time, the house was not done and I had a rainstorm up stairs one day, did not take me long to learn about ventilation.
can an ice storm insulate a house?
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ArsenalDon
Minister of Fire
The Igloo concept. Plug up all of the air holes and instant insulation. Love your Queen Avatar! News of the World. The greatest Rock band of all time.
ArsenalDon
Minister of Fire
futurama looks just like the robot from the news of the world album cover?
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jdp1152
Minister of Fire
The baffles are not so much a vapor barrier, as they are a separator between the bottom of the roof deck and the insulation.
When insulation rests right up to the bottom of the roof decking, the bottom of the decking rots out and in many instances has mold form on the unventilated underside, due to condensation of any conditioned air leakage from the living area to the cavity under the decking. Even if there is no condensation and mold, the bottom of the roof deck can dry rot, again due to no or inadequate ventilation, which keeps the bottom side of the decking from breathing. As far as closed cell sprayed foam, I do not know the long term effects or not, of the decking not being able to breath or if dry rot occurs or not.
I still believe you might need a vapor barrier between the conditioned area and the foam depending on which type of foam is used. We used to install polyiso board decking which consisted of osb or plywood, with the iso attached to that, then a vented paper backing on the bottom(all factory made as a modular unit). It seemed the decking wood, iso and paper backing were all set up to breath. This set up was also on top of a corrugated metal decking, so not the standard house set up.
In my experience, when things that are normally able to breathe, are made not able to breathe, there are repercussions that follow. Wood in any form needs to breathe, contract, expand etc.
Another first hand example: There is a local bar/restaurant we do family night out at once in a while. They spray foamed the inside over & between the roof rafters, spraying the foam directly to the bottom side of the deck and rafters etc. It did not take long for the wood rafters and decking to move enough to pop the insulation loose along the sides of the rafters. Can't tell on the bottom side of the decking if it has loosened or not, but it is still in place so far. It is very noticeable as the bottom side of the foam was painted black, and you can see where the foam has separated from the rafters as there is a very visible white area of the foam along the areas that the separation occurred. Of course the bar is not worried and has left it as is.
When insulation rests right up to the bottom of the roof decking, the bottom of the decking rots out and in many instances has mold form on the unventilated underside, due to condensation of any conditioned air leakage from the living area to the cavity under the decking. Even if there is no condensation and mold, the bottom of the roof deck can dry rot, again due to no or inadequate ventilation, which keeps the bottom side of the decking from breathing. As far as closed cell sprayed foam, I do not know the long term effects or not, of the decking not being able to breath or if dry rot occurs or not.
I still believe you might need a vapor barrier between the conditioned area and the foam depending on which type of foam is used. We used to install polyiso board decking which consisted of osb or plywood, with the iso attached to that, then a vented paper backing on the bottom(all factory made as a modular unit). It seemed the decking wood, iso and paper backing were all set up to breath. This set up was also on top of a corrugated metal decking, so not the standard house set up.
In my experience, when things that are normally able to breathe, are made not able to breathe, there are repercussions that follow. Wood in any form needs to breathe, contract, expand etc.
Another first hand example: There is a local bar/restaurant we do family night out at once in a while. They spray foamed the inside over & between the roof rafters, spraying the foam directly to the bottom side of the deck and rafters etc. It did not take long for the wood rafters and decking to move enough to pop the insulation loose along the sides of the rafters. Can't tell on the bottom side of the decking if it has loosened or not, but it is still in place so far. It is very noticeable as the bottom side of the foam was painted black, and you can see where the foam has separated from the rafters as there is a very visible white area of the foam along the areas that the separation occurred. Of course the bar is not worried and has left it as is.
Yea I made my own baffles, after 25 years they stripped the shingles and the plywood looked perfect.
I agree with you Hog, not sure I want to seal everything up like a tuna can.
I agree with you Hog, not sure I want to seal everything up like a tuna can.
Ashful
Minister of Fire
I'm with you on everything but this last statement, Hog. There have been several recent studies done on asphalt shingles, most showing that the ventilation of the attic (via soffit/ridge or gable venting) makes very little difference in shingle or underlayment temperatures. Something like 5*F, in most cases, on a roof sitting at 125F - 150F in the summer sun. There's some discussion in the industry about removing the ventillation requirement, with respect to shingle and underlayment warranties.
Ventillation provides services beyond just keeping the shingles or underlayment cool, though.
Everyone can do what they think is right or has proof it is right. I have an 1870's house with a granite boulder foundation on an area covered in ledge. The basement gas leaks I am aware of and I let them be they are not that big but obvious. The catch is houses with that type of foundation you get told to seal them up so you save X amount of fuel during the year. Then they tell you to vent the cellar because with a foundation like mine there is a very good chance of radon gas filling the house and it can kill you. I have an attic that does not have soffit vents but do have old style attic vets near the peaks and the half wall ceilings are wide open to the attic another heat loser. I do have insulation on the attic floor and no vapor barrier as there is no way to really seal it without tearing out perfect plaster ceilings. Not going to happen in my life..About 15 years ago I have the entire roof stripped right down the the stringers for the original cedar shingles and they were perfect along with all the rood rafters. So yes modern construction might be nice but will stick with my close to 140 year old place with no radon to kill me an little to no rot. Had to change about 15 feet of sills due to water getting in but the rest perfect after all that time. Once you seal everything you have to make sure it is perfectly sealed and then add make up air for everything that might use it. Exhaust fans wood stove furnace water heaters etc. plus the air gets stagnant with the same things never getting purged. It is not healthy to keep re breathing the same air. My thoughts maybe all wrong maybe partially right but I would rather trade a cord of wood or a bit of fuel oil for a sound house and good health.
I'll just add two cents to say very simply that everything that Hogwildz has said here is spot on and I'm sorry to say but the buildingscience article is actually only part of the overall picture; what is built in sterile laboratory settings and tested without the "benefit" of being attacked by earth, elements, gravity and time is not necessarily going to give a good long term look at any particular system within real world situations. And I'd argue that any new construction actually constructed this way truly has yet to prove itself for those same reasons.
It is pretty well known fact that over time many maybe most options of foam degrade in their insulating ability and on top of that with the shifting and settling of all structures, sooner or later there is going to be the ability for moisture to make its way into something and start problems. The tighter the area the moisture makes its way into the worse the result especially over extended time.
I am not saying this from theories within my mind; even though I am not actually a builder I have an admirable amount of experience building houses from the foundation to the roof as well as spending time trying to fix things which went wrong from a moisture management perspective and then afterwards spending time trying to figure out what really works best. The answer is always to understand that ultimately you can only slow water not stop water (heck even Confucius told us that) and when it comes to attics that means you must ventilate, ventilate, ventilate.
It is pretty well known fact that over time many maybe most options of foam degrade in their insulating ability and on top of that with the shifting and settling of all structures, sooner or later there is going to be the ability for moisture to make its way into something and start problems. The tighter the area the moisture makes its way into the worse the result especially over extended time.
I am not saying this from theories within my mind; even though I am not actually a builder I have an admirable amount of experience building houses from the foundation to the roof as well as spending time trying to fix things which went wrong from a moisture management perspective and then afterwards spending time trying to figure out what really works best. The answer is always to understand that ultimately you can only slow water not stop water (heck even Confucius told us that) and when it comes to attics that means you must ventilate, ventilate, ventilate.
I think you guys are being too tough on Building Science. I think they've brought a lot of common sense to construction science and developed a large body of knowledge based not only on research but extensive field observations. I also know they are willing to admit their errors bases on field observations.
I know of one article where they detail how their own attempts at an energy makeover of their office was years later dissected to discover what problems had occurred (in real life) and how to prevent them. http://www.buildingscience.com/documents/published-articles/pa-foam-shrinks/view?searchterm=foam shrinks
Interestingly this article discusses some of the issues that Howwildz brought up, namely shrinking foam.
KodiakII
Minister of Fire
I wish freezing rain did insulate, we are on our second day of the danged stuff...give me good old fashioned snow any day!
Just for what its worth I'm not trying to be too tough on them but anyone who actually tries to construct their project that way will ultimately regret it if they stay there long enough to observe the resulting problems.
and,
Just give it time (along with earth, elements and gravity) and I'm sure that they will willingly admit their error but not their liability. In other words they will tell you it is your fault for listening to them. DOH!
Edit: I should add that there are plenty of things on their site that I actually agree about but attempting to seal the attic isn't one of those things.
Seems to be too much emotion in this topic for my taste...I prefer science and facts. Remember the original topic of this post: why insulation due to ice storm. I posted my postulation.
A few points of clarification for those interested. If anyone wants more specific info, please PM as it does not really belong in this heading.
1: I used Building science as only about 20% of my reference basis; one of many references to make my construction choices. Just because I provided a reference, as requested by eatenbylimestone, no one should interpret it as the final word, but rather a starting point of the investigation.
2: I used 5 different insulation types in the construction process. Each tested and chosen to meet the required criteria for the installed location.
3: I have spoken with Corning engineering staff (as I was dealing with them an a separate matter) about fiberglass and foam. This conversation influenced my decision. No, I didn't use any of their products.
4: My house has a large amount of HVAC duct work in the attic.
5: We use all of the attic for storage. The Foam keeps the attic within 10deg of the conditioned area temp year round. Our stuff no longer seen temp and humidity swings.
6: I did the house as a test for the standard "vented attic" and conducted testing for 1/2 of a winter, spring, and 3/4 of the summer using the standard vented design. Yes, it required more work and some undoing of construction, but I like testing, and verification as I plan on being in the house for the next 40 years.
7: After phase2, converting to unvented, the house became much more comfortable. Even visitors comment of how even the entire house is compared to phase1.
8: I have a significant air filter/exchange system in the HVAC. I can run this even in the winter because I have the attic sealed and therefore the ducts don't cool the house when circulating. This is something many have tried to do while heating with a wood stove.
9: I will post my results on the building construction forums when enough time has passed. I do monitor the full envelope and all is well presently including cavity humidity, mold, and insulation shrinkage.
10: This is applicable to some existing houses if the existing vapor barrier can be removed, among other requirements. As with any choice in life where one deviates from the accepted standard, you should do lots amounts of research and take full responsibility. Done improperly, foam can lead to significant problems and has in the past.
I realize this is not for every house or every person. That is the beauty of this country (as originally founded); freedom. Be thankful we all are different.
A few points of clarification for those interested. If anyone wants more specific info, please PM as it does not really belong in this heading.
1: I used Building science as only about 20% of my reference basis; one of many references to make my construction choices. Just because I provided a reference, as requested by eatenbylimestone, no one should interpret it as the final word, but rather a starting point of the investigation.
2: I used 5 different insulation types in the construction process. Each tested and chosen to meet the required criteria for the installed location.
3: I have spoken with Corning engineering staff (as I was dealing with them an a separate matter) about fiberglass and foam. This conversation influenced my decision. No, I didn't use any of their products.
4: My house has a large amount of HVAC duct work in the attic.
5: We use all of the attic for storage. The Foam keeps the attic within 10deg of the conditioned area temp year round. Our stuff no longer seen temp and humidity swings.
6: I did the house as a test for the standard "vented attic" and conducted testing for 1/2 of a winter, spring, and 3/4 of the summer using the standard vented design. Yes, it required more work and some undoing of construction, but I like testing, and verification as I plan on being in the house for the next 40 years.
7: After phase2, converting to unvented, the house became much more comfortable. Even visitors comment of how even the entire house is compared to phase1.
8: I have a significant air filter/exchange system in the HVAC. I can run this even in the winter because I have the attic sealed and therefore the ducts don't cool the house when circulating. This is something many have tried to do while heating with a wood stove.
9: I will post my results on the building construction forums when enough time has passed. I do monitor the full envelope and all is well presently including cavity humidity, mold, and insulation shrinkage.
10: This is applicable to some existing houses if the existing vapor barrier can be removed, among other requirements. As with any choice in life where one deviates from the accepted standard, you should do lots amounts of research and take full responsibility. Done improperly, foam can lead to significant problems and has in the past.
I realize this is not for every house or every person. That is the beauty of this country (as originally founded); freedom. Be thankful we all are different.
Gee I guess I missed that; I didn't see much emotion expressed from anyone and the "science" I saw was flawed as far as what BS published. Facts come from experience and expertise not just experiments. In fact "science" itself will indicate the validity of any experiment or any data is directly correlated and connected to how many times that experiment or that data can be replicated. So the "experiment" of ventilating attic areas has been proven beyond any doubt as effective while the "experiment" of sealing attic areas has not unless one would consider such short term data as definitive. Several helpful folks here have tried to help others by offering experience and expertise from years and years of, well, experience and expertise. If that is emotional for anyone we apologize.
Some related tech bulletins from shingle makers:
(broken link removed to http://forums.finehomebuilding.com/sites/forums.finehomebuilding.com/files/comment_upload/74187/Bulletin_-_Elk_Shingles_-_TBSD_001.pdf)
(broken link removed to http://forums.finehomebuilding.com/sites/forums.finehomebuilding.com/files/comment_upload/74187/CertainTeed_-_Tech_Bulletin_-_Unvented_Roof_Decks.pdf)
(broken link removed to http://forums.finehomebuilding.com/sites/forums.finehomebuilding.com/files/comment_upload/74187/Elk_-_Fact_Sheet_-_Spray_In_Place.pdf)
All the pages state you can go over spray foamed applications on underside of deck, and all also state "2) provision of adequate structural ventilation and/or vapor retarders as determined to be necessary"
Bottom line is, 95% or more of homes do not have spray foam, as it is too expensive for builders to sink money into, as well as home owners.
Let it go already.
I just came across those links, and the information in them, yesterday and thought they related to this thread.
Your post seemed the right one to quote since the tech briefs at those links were an addendum to the warranties you posted.
No reason to get defensive.
Defensive? Your perception is off. Not defensive, just a plain old statement.
Now some facts.
The bulletins your posting are from 2003, 2004 & 2005, and also from yet another site that sells subscriptions & products that are not their own.
I myself go direct to the manufacturers site(s) and rear their installation instructions and warranty, after all they make the product, who would know their product and requirements better then them?
Elk, is no longer, has been no longer for quite a few years now. GAF bought out Elk. So your documentation referring to them is no longer relevent.
GAF's warranty is one I posted and it clearly states, any damage caused due to inadequate ventilation is NOT covered by the warranty.
The direct quote from the manufacturer's installation instructions most recently dated 4/2012 is as follows:
THROUGH VENTILATION: For optimal shingle life and to help prevent mold growth, all roof structures must have through ventilation to prevent
entrapment of moisture-laden air behind roof sheathing. Ventilation must be designed to meet or exceed current F.H.A., H.U.D., or local code
minimum requirements. Note: Minimum net free ventilation area of 1 sq. foot per 150 sq. feet (1 sq. meter per 150 sq. meters) of ceiling area
is required. When vents are located at the eaves and near the roof’s peak (balanced) for maximum air flow, ventilation may be reduced to 1 sq.
foot per 300 sq. feet (1 sq. meter per 300 sq. meters).
Per the manufacturer's warranty:
What Is Not Covered
Even if your shingles or accessories were not properly installed according to GAF’s application
instructions or to standard good roofing practices, this Limited Warranty remains
in effect. However, GAF will NOT compensate you for:
(1) Damages resulting from anything other than an inherent manufacturing defect in your
shingles or accessories, such as:
(a) Improper fastening of your shingles or accessories or application not in strict
accordance with GAF’s printed application instructions, if the improper installation
was the cause of the damage.
(b) Settlement, movement, or defects in the building, walls, foundation, or the roof
base over which the shingles or accessories were applied.
(c) Inadequate attic ventilation.
(2) Damages resulting from causes beyond normal wear and tear, such as:
(a) acts of nature, such as hail, fire, winds (including gusts) over the applicable wind
speed listed above, or ice damming above the areas of your roof deck covered by
a GAF Waterproof Leak Barrier.
(b) impact of foreign objects or traffic on the roof.
(c) improper storage or handling of shingles or accessories.
(3) Shading or variations in the color of your shingles or ridge cap shingles or discoloration
or contamination caused by fungus, mold, lichen, algae (except for blue-green
algae if your shingles or ridge cap shingles were labeled with the StainGuard® logo),
or other contaminants, including that caused by organic materials on the roof.
(4) Labor costs, except as specifically provided for above, disposal costs, tear-off costs,
and costs related to underlayments (unless your claim involves a manufacturing
defect in a GAF Underlayment), metal work, and flashings.
(5) Damage to the interior or exterior of the building, including, but not limited to,
mold growth.
I am obtaining my info from hands on experience, and manufacturers documents.
Docs from any other sites, especially ones that have a purpose to sell products on those sites, are BS as far as I am concerned, as they have a specific motive.
Not faulting them, business is business. But just because they post pdfs and articles, means nothing. Reference materials at best, and sometimes good info, sometimes poor info.
Further: Add HVAC equipment , ductwork etc to the attic space. Any leaks in the duct is going to equal not good. Any equipment will needs ventilation/air circulation, as well as the space around it.
As far as an attic staying within 10 degrees of the conditioned space below it, either it is open to below allowing that same conditioned air into the attic space, intentionally conditioned, or not very well insulated in the ceiling below. Even the best insulated cooler on a hot or cold day will eventually end up near the same temp as outside without any cool or heat packs inside to hold temps. Sorry there is no magic foam or any other insulation that will condition space on its own, or retain a certain temp of that space contained on it's own. Not without an exchange of some conditioned air or equipment.
I said all I have to say on this topic. Have at it.
Now some facts.
The bulletins your posting are from 2003, 2004 & 2005, and also from yet another site that sells subscriptions & products that are not their own.
I myself go direct to the manufacturers site(s) and rear their installation instructions and warranty, after all they make the product, who would know their product and requirements better then them?
Elk, is no longer, has been no longer for quite a few years now. GAF bought out Elk. So your documentation referring to them is no longer relevent.
GAF's warranty is one I posted and it clearly states, any damage caused due to inadequate ventilation is NOT covered by the warranty.
The direct quote from the manufacturer's installation instructions most recently dated 4/2012 is as follows:
THROUGH VENTILATION: For optimal shingle life and to help prevent mold growth, all roof structures must have through ventilation to prevent
entrapment of moisture-laden air behind roof sheathing. Ventilation must be designed to meet or exceed current F.H.A., H.U.D., or local code
minimum requirements. Note: Minimum net free ventilation area of 1 sq. foot per 150 sq. feet (1 sq. meter per 150 sq. meters) of ceiling area
is required. When vents are located at the eaves and near the roof’s peak (balanced) for maximum air flow, ventilation may be reduced to 1 sq.
foot per 300 sq. feet (1 sq. meter per 300 sq. meters).
Per the manufacturer's warranty:
What Is Not Covered
Even if your shingles or accessories were not properly installed according to GAF’s application
instructions or to standard good roofing practices, this Limited Warranty remains
in effect. However, GAF will NOT compensate you for:
(1) Damages resulting from anything other than an inherent manufacturing defect in your
shingles or accessories, such as:
(a) Improper fastening of your shingles or accessories or application not in strict
accordance with GAF’s printed application instructions, if the improper installation
was the cause of the damage.
(b) Settlement, movement, or defects in the building, walls, foundation, or the roof
base over which the shingles or accessories were applied.
(c) Inadequate attic ventilation.
(2) Damages resulting from causes beyond normal wear and tear, such as:
(a) acts of nature, such as hail, fire, winds (including gusts) over the applicable wind
speed listed above, or ice damming above the areas of your roof deck covered by
a GAF Waterproof Leak Barrier.
(b) impact of foreign objects or traffic on the roof.
(c) improper storage or handling of shingles or accessories.
(3) Shading or variations in the color of your shingles or ridge cap shingles or discoloration
or contamination caused by fungus, mold, lichen, algae (except for blue-green
algae if your shingles or ridge cap shingles were labeled with the StainGuard® logo),
or other contaminants, including that caused by organic materials on the roof.
(4) Labor costs, except as specifically provided for above, disposal costs, tear-off costs,
and costs related to underlayments (unless your claim involves a manufacturing
defect in a GAF Underlayment), metal work, and flashings.
(5) Damage to the interior or exterior of the building, including, but not limited to,
mold growth.
I am obtaining my info from hands on experience, and manufacturers documents.
Docs from any other sites, especially ones that have a purpose to sell products on those sites, are BS as far as I am concerned, as they have a specific motive.
Not faulting them, business is business. But just because they post pdfs and articles, means nothing. Reference materials at best, and sometimes good info, sometimes poor info.
Further: Add HVAC equipment , ductwork etc to the attic space. Any leaks in the duct is going to equal not good. Any equipment will needs ventilation/air circulation, as well as the space around it.
As far as an attic staying within 10 degrees of the conditioned space below it, either it is open to below allowing that same conditioned air into the attic space, intentionally conditioned, or not very well insulated in the ceiling below. Even the best insulated cooler on a hot or cold day will eventually end up near the same temp as outside without any cool or heat packs inside to hold temps. Sorry there is no magic foam or any other insulation that will condition space on its own, or retain a certain temp of that space contained on it's own. Not without an exchange of some conditioned air or equipment.
I said all I have to say on this topic. Have at it.
Wow. Yep. Building science says you can have vented attics outside the envelope (insulated attic floor), or unvented attics inside the envelope (insulated roof deck). The first one is usually cheaper...the second is more expensive but makes sense in certain circumstances.
And while we are arguing about it....the majority of attics are disasters that are not in either category approved by building science....leaking huge amounts of conditioned air into a vented attic space...wasting 20+% of total energy usage, causing attic mold, ice dams, etc.
And while we are arguing about it....the majority of attics are disasters that are not in either category approved by building science....leaking huge amounts of conditioned air into a vented attic space...wasting 20+% of total energy usage, causing attic mold, ice dams, etc.
That I completely agree with.
Of course someone will post some site's info to dispute that also. LMAO
Note: Other posts between these two omitted.
It think my posts state clearly support that a well ventilated attic is a good thing. Also clearly stated is that BS's and other's proposals for unvented attics apply primarily to cathedral ceilings. It would seem that "inadequate attic ventilation" above does not pertain to cathedral ceilings which is I've been primarily talking about. I think if they (the manufacturer) meant the "roof deck" they would have stated that.
69911e's post that started this debate did not specify whether we were talking about a roof over an attic or one over a cathedral ceiling.
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