[Greenbuilding] Conversation/Listserv Format

Allison Friedman afriedman at rateitgreen.com
Sun Dec 11 12:37:37 MST 2016


If this format is really working for everyone, great.  

If not, and it used to come up every few years, let me know if I can help.  I am not saying that I have found the perfect solution, but with your help (feedback and info posted) I'd have a better shot at delivering it - for everyone.  (Last time this question came up a few years ago, I was still working to make things work “foundationally," as I wanted.)  

I honestly can’t follow these conversations when they get long.  And more importantly, the answers aren’t seen out side the group. Why not have the solutions shared reach more people?

I am glad to see more activity recently. Honestly, this group of people makes me believe that more is known and more is getting done to build better and greener than most people know.  Still, we need hundreds of thousands of people talking like this.  And I want people to be able to learn from those who have come before.  

Here are our groups so far.  The site can handle any topic, or type of categorization.  If we don’t have it, I’ll just add it.  

http://www.rateitgreen.com/green-building-community/sustainable-building-groups-all

If moving to a platform is of interest, find me.  If not, well I will still be here. These 10 replies just made me think of brining the idea back up.  You want to be able to categorize your own ideas, and I think we can do so much more if others can see the information as well.  (information in groups lives in groups, but can also optionally “cross post” to discussions so others can find it by topic). 


Thanks for doing what you all do.  I will help when I see questions I can help with (or find someone to help with), regardless.  
Allison


Allison Friedman
Rate It Green
www.rateitgreen.com
@rateitgreen
@MAGreenbuilding


Rate It Green is a directory, network, and information resource for the green building industry. 
Rate It Green welcomes all green builders, from beginners to seasoned experts, and for both residential and commercial projects.  
Individual Membership and Basic Company Listings are free of charge.






On Dec 11, 2016, at 2:00 PM, greenbuilding-request at lists.bioenergylists.org wrote:

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> Today's Topics:
> 
>   1. Unvented cathedral ceiling condensation (Leslie Moyer)
>   2. Re: Unvented cathedral ceiling condensation (Reuben Deumling)
>   3. Re: Unvented cathedral ceiling condensation (Norbert Senf)
>   4. Re: Unvented cathedral ceiling condensation (Jason Holstine)
>   5. Re: Unvented cathedral ceiling condensation (Michael O'Brien)
>   6. Re: Unvented cathedral ceiling condensation (Norbert Senf)
>   7. Re: Unvented cathedral ceiling condensation (Leslie Moyer)
>   8. Re: Unvented cathedral ceiling condensation (Jeff Martin)
>   9. Re: Unvented cathedral ceiling condensation (Norbert Senf)
>  10. Re: Unvented cathedral ceiling condensation (Reuben Deumling)
>  11. Re: Unvented cathedral ceiling condensation (Michael O'Brien)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sat, 10 Dec 2016 11:50:53 -0800
> From: "Leslie Moyer" <unschooler at lrec.org>
> To: <greenbuilding at lists.bioenergylists.org>
> Cc: <ThreeSpringsFarmers at gmail.com>
> Subject: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <20161210115053.E7F3CC61 at m0087797.ppops.net>
> Content-Type: text/plain; charset="us-ascii"
> 
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> ------------------------------
> 
> Message: 2
> Date: Sat, 10 Dec 2016 12:21:10 -0800
> From: Reuben Deumling <9watts at gmail.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID:
> 	<CAE5fceDTd-J9uEKHtPN8a71=dA48BDMOcAnCtE9y=Kx3hDDOxg at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> A delightful article. Thank you for sending that, and very timely for me.
> One thing that occurs to me when reading it is that we here in the PNW
> whose humidity profile is basically the reverse of much of the rest of the
> country, or at least of much of the rest of the inhabited part of the
> country, tend to be forgotten. I don't know if it makes much difference to
> these questions of moisture management, but it seems like it probably
> would.
> 
> Finally I have to say this paragraph (which contradicts the rest of the
> article) made me laugh:
> *However, in some areas of the country, especially in the Northeast,
> insulation contractors have been dense-packing unvented rafter bays with
> cellulose for years. Because the method has deep roots in New England, many
> building inspectors accept such installations.*
> 
> 
> 
> 
> On Sat, Dec 10, 2016 at 11:50 AM, Leslie Moyer <unschooler at lrec.org> wrote:
> 
>> I have some nearby friends having a problem. I think I understand what the
>> problem is, and even some possible ways to solve it, but I'm not certain I
>> could give them advice that would fix their problem the best or cheapest
>> way. I thought you guys could, though!
>> 
>> They read this article & I think they will go ahead and pay to read the
>> article referenced within it:
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-
>> insulated-cathedral-ceiling
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral
>> ceiling.  We live in northeastern Oklahoma (zone 3) and just added a
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just
>> opened up to the main house earlier this week, and we got hit with (what
>> are for us) very cold temperatures.  Thursday night had a low of 12 F.  By
>> noon on Friday we noticed that water was dripping down the north side
>> interior wall  (along the drywall).  The drip lines appeared to be spaced
>> every 24 inches, or about where a roof rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  The
>> interior ceiling is wooden tongue and groove car siding.   The roof decking
>> is LP TechShield Radiant Barrier (with the metal foil side facing the
>> interior of the house, as described on the boards) with a metal roof (there
>> is felt paper in between the decking and the metal roof on the North side,
>> but on the South side we used double bubble).   We did not have any
>> condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re getting
>> as many different suggested solutions.  We are desperate to fix this
>> problem and would greatly appreciate any help!  Thank you!
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
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> ------------------------------
> 
> Message: 3
> Date: Sat, 10 Dec 2016 15:26:22 -0500
> From: Norbert Senf <norbert.senf at gmail.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID:
> 	<CAGYvK4f3bpC2nSSqinpbWKXutGxHH7iRHyGpgWYyCesNGSoBmA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> I'm guessing no decent vapor barrier detail on the warm side. The house
> acts like a chimney in cold weather, with the highest positive pressure at
> the cathedral ceiling. Air is going through the Roxul and hitting the
> bottom of the roof and condensing. Very commonly,  a poorly detailed pot
> light will do this. In southern climes where they are not used to airtight
> construction, it would be very unusual for somebody to know how to properly
> vapor barrier a pot light in a cathedral ceiling..................Norbert
> 
> 
> On Sat, Dec 10, 2016 at 2:50 PM, Leslie Moyer <unschooler at lrec.org> wrote:
> 
>> I have some nearby friends having a problem. I think I understand what the
>> problem is, and even some possible ways to solve it, but I'm not certain I
>> could give them advice that would fix their problem the best or cheapest
>> way. I thought you guys could, though!
>> 
>> They read this article & I think they will go ahead and pay to read the
>> article referenced within it:
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-
>> insulated-cathedral-ceiling
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral
>> ceiling.  We live in northeastern Oklahoma (zone 3) and just added a
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just
>> opened up to the main house earlier this week, and we got hit with (what
>> are for us) very cold temperatures.  Thursday night had a low of 12 F.  By
>> noon on Friday we noticed that water was dripping down the north side
>> interior wall  (along the drywall).  The drip lines appeared to be spaced
>> every 24 inches, or about where a roof rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  The
>> interior ceiling is wooden tongue and groove car siding.   The roof decking
>> is LP TechShield Radiant Barrier (with the metal foil side facing the
>> interior of the house, as described on the boards) with a metal roof (there
>> is felt paper in between the decking and the metal roof on the North side,
>> but on the South side we used double bubble).   We did not have any
>> condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re getting
>> as many different suggested solutions.  We are desperate to fix this
>> problem and would greatly appreciate any help!  Thank you!
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
> 
> 
> 
> -- 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Qu?bec J0X 2Y0
> 819.647.5092
> www.heatkit.com
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> ------------------------------
> 
> Message: 4
> Date: Sat, 10 Dec 2016 15:56:57 -0500
> From: Jason Holstine <jason at amicusgreen.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <6CBDB120-7AB3-4C20-BE3A-C860925067A0 at amicusgreen.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Vapor barrier or simply an air seal?
> 
> 
> 
> 
> 
> From: Greenbuilding <greenbuilding-bounces at lists.bioenergylists.org> on behalf of Norbert Senf <norbert.senf at gmail.com>
> Reply-To: Green Building <greenbuilding at lists.bioenergylists.org>
> Date: Saturday, December 10, 2016 at 3:26 PM
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> 
> 
> 
> I'm guessing no decent vapor barrier detail on the warm side. The house acts like a chimney in cold weather, with the highest positive pressure at the cathedral ceiling. Air is going through the Roxul and hitting the bottom of the roof and condensing. Very commonly,  a poorly detailed pot light will do this. In southern climes where they are not used to airtight construction, it would be very unusual for somebody to know how to properly vapor barrier a pot light in a cathedral ceiling..................Norbert
> 
> 
> 
> On Sat, Dec 10, 2016 at 2:50 PM, Leslie Moyer <unschooler at lrec.org> wrote:
> 
> I have some nearby friends having a problem. I think I understand what the problem is, and even some possible ways to solve it, but I'm not certain I could give them advice that would fix their problem the best or cheapest way. I thought you guys could, though!  
> 
> 
> 
> They read this article & I think they will go ahead and pay to read the article referenced within it: 
> 
> 
> 
> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling
> 
> 
> 
> We are considered a "hot humid" climate--NE Oklahoma 
> 
> ???????????.
> 
> We have a question regarding condensation problems in a cathedral ceiling.  We live in northeastern Oklahoma (zone 3) and just added a dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just opened up to the main house earlier this week, and we got hit with (what are for us) very cold temperatures.  Thursday night had a low of 12 F.  By noon on Friday we noticed that water was dripping down the north side interior wall  (along the drywall).  The drip lines appeared to be spaced every 24 inches, or about where a roof rafter would be.
> 
> The ceiling/roof construction was constructed with 2 x 8 rafters and insulated with R30 Roxul (rock wool) insulation and is not vented.  The interior ceiling is wooden tongue and groove car siding.   The roof decking is LP TechShield Radiant Barrier (with the metal foil side facing the interior of the house, as described on the boards) with a metal roof (there is felt paper in between the decking and the metal roof on the North side, but on the South side we used double bubble).   We did not have any condensation issues on the south wall.
> 
> We have spoken with over half a dozen different experts, and we?re getting as many different suggested solutions.  We are desperate to fix this problem and would greatly appreciate any help!  Thank you!
> 
> 
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
> 
> 
> 
> 
> -- 
> 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Qu?bec J0X 2Y0
> 819.647.5092
> www.heatkit.com
> 
> _______________________________________________ Greenbuilding mailing list to Send a Message to the list, use the email address Greenbuilding at bioenergylists.org to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
> 
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> ------------------------------
> 
> Message: 5
> Date: Sat, 10 Dec 2016 13:38:28 -0800
> From: "Michael O'Brien" <obrien at hevanet.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <81E1D91A-DEFC-4931-A26E-334B4071C183 at hevanet.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi, Leslie?
> 
> Just wanted to chime in to agree about the air leaks across the interior side of the cathedral ceiling. Not only recessed can fixtures, but often every wiring hole drilled through top plates, every vent stack and flue have not been sealed to block air leaks. The walls may be contributing, too, if there are penetrations in the top plates. 
> 
> The long-term fix is to take down the ceiling drywall so the leaks can be sealed and a proper vapor rertarder installed, but in the short term they could run a dehumidifier to reduce the water vapor in their occupied space. 
> 
> Sometimes builders will open up the blocks along the eaves and install some sort of vent at or near the ridge, but this may have the effect of sending cold air under the insulation and cooling down the interior surface of the ceiling, it takes some detailing to keep the vent air above the insulation.
> 
> Best wishes,
> 
> Mike O?Brien
> 
> 
> 
> On Dec 10, 2016, at 11:50 AM, Leslie Moyer <unschooler at lrec.org> wrote:
> 
> I have some nearby friends having a problem. I think I understand what the problem is, and even some possible ways to solve it, but I'm not certain I could give them advice that would fix their problem the best or cheapest way. I thought you guys could, though!  
> 
> They read this article & I think they will go ahead and pay to read the article referenced within it: 
> 
> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling
> 
> We are considered a "hot humid" climate--NE Oklahoma 
> ???????????.
> 
> We have a question regarding condensation problems in a cathedral ceiling.  We live in northeastern Oklahoma (zone 3) and just added a dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just opened up to the main house earlier this week, and we got hit with (what are for us) very cold temperatures.  Thursday night had a low of 12 F.  By noon on Friday we noticed that water was dripping down the north side interior wall  (along the drywall).  The drip lines appeared to be spaced every 24 inches, or about where a roof rafter would be.
> 
> The ceiling/roof construction was constructed with 2 x 8 rafters and insulated with R30 Roxul (rock wool) insulation and is not vented.  The interior ceiling is wooden tongue and groove car siding.   The roof decking is LP TechShield Radiant Barrier (with the metal foil side facing the interior of the house, as described on the boards) with a metal roof (there is felt paper in between the decking and the metal roof on the North side, but on the South side we used double bubble).   We did not have any condensation issues on the south wall.
> 
> We have spoken with over half a dozen different experts, and we?re getting as many different suggested solutions.  We are desperate to fix this problem and would greatly appreciate any help!  Thank you!
> _______________________________________________
> Greenbuilding mailing list
> to Send a Message to the list, use the email address
> Greenbuilding at bioenergylists.org
> 
> to UNSUBSCRIBE or Change your List Settings use the web page
> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
> 
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> ------------------------------
> 
> Message: 6
> Date: Sat, 10 Dec 2016 17:44:10 -0500
> From: Norbert Senf <norbert.senf at gmail.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID:
> 	<CAGYvK4ducyHVBqh41X_pc7XGZAdqGwd4pqyFXp2HZe=WDH4ihA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> We call it a vapour barrier, because normally it is 6 mil special poly. But
> actually, it is the air seal that is doing the work. Bulk air movement is
> the issue. Vapor diffusion is a very minor concern..........N
> 
> On Sat, Dec 10, 2016 at 3:56 PM, Jason Holstine <jason at amicusgreen.com>
> wrote:
> 
>> Vapor barrier or simply an air seal?
>> 
>> 
>> 
>> 
>> 
>> *From: *Greenbuilding <greenbuilding-bounces at lists.bioenergylists.org> on
>> behalf of Norbert Senf <norbert.senf at gmail.com>
>> *Reply-To: *Green Building <greenbuilding at lists.bioenergylists.org>
>> *Date: *Saturday, December 10, 2016 at 3:26 PM
>> *To: *Green Building <greenbuilding at lists.bioenergylists.org>
>> *Subject: *Re: [Greenbuilding] Unvented cathedral ceiling condensation
>> 
>> 
>> 
>> I'm guessing no decent vapor barrier detail on the warm side. The house
>> acts like a chimney in cold weather, with the highest positive pressure at
>> the cathedral ceiling. Air is going through the Roxul and hitting the
>> bottom of the roof and condensing. Very commonly,  a poorly detailed pot
>> light will do this. In southern climes where they are not used to airtight
>> construction, it would be very unusual for somebody to know how to properly
>> vapor barrier a pot light in a cathedral ceiling..................Norbert
>> 
>> 
>> 
>> On Sat, Dec 10, 2016 at 2:50 PM, Leslie Moyer <unschooler at lrec.org> wrote:
>> 
>> I have some nearby friends having a problem. I think I understand what the
>> problem is, and even some possible ways to solve it, but I'm not certain I
>> could give them advice that would fix their problem the best or cheapest
>> way. I thought you guys could, though!
>> 
>> 
>> 
>> They read this article & I think they will go ahead and pay to read the
>> article referenced within it:
>> 
>> 
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-
>> insulated-cathedral-ceiling
>> 
>> 
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> 
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral
>> ceiling.  We live in northeastern Oklahoma (zone 3) and just added a
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just
>> opened up to the main house earlier this week, and we got hit with (what
>> are for us) very cold temperatures.  Thursday night had a low of 12 F.  By
>> noon on Friday we noticed that water was dripping down the north side
>> interior wall  (along the drywall).  The drip lines appeared to be spaced
>> every 24 inches, or about where a roof rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  The
>> interior ceiling is wooden tongue and groove car siding.   The roof decking
>> is LP TechShield Radiant Barrier (with the metal foil side facing the
>> interior of the house, as described on the boards) with a metal roof (there
>> is felt paper in between the decking and the metal roof on the North side,
>> but on the South side we used double bubble).   We did not have any
>> condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re getting
>> as many different suggested solutions.  We are desperate to fix this
>> problem and would greatly appreciate any help!  Thank you!
>> 
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
>> 
>> 
>> 
>> --
>> 
>> Norbert Senf
>> Masonry Stove Builders
>> 25 Brouse Road, RR 5
>> Shawville Qu?bec J0X 2Y0
>> 819.647.5092 <(819)%20647-5092>
>> www.heatkit.com
>> 
>> _______________________________________________ Greenbuilding mailing
>> list to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org to UNSUBSCRIBE or Change your List
>> Settings use the web page http://lists.bioenergylists.
>> org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
> 
> 
> 
> -- 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Qu?bec J0X 2Y0
> 819.647.5092
> www.heatkit.com
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> ------------------------------
> 
> Message: 7
> Date: Sat, 10 Dec 2016 18:20:36 -0800
> From: "Leslie Moyer" <unschooler at lrec.org>
> To: "Green Building" <greenbuilding at lists.bioenergylists.org>
> Cc: "Mike Appel" <ThreeSpringsFarmers at gmail.com>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <20161210182036.E7F1DAE0 at m0087793.ppops.net>
> Content-Type: text/plain; charset="us-ascii"
> 
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> ------------------------------
> 
> Message: 8
> Date: Sun, 11 Dec 2016 10:58:04 -0500
> From: Jeff Martin <jeff at open2learn.ca>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Cc: Mike Appel <ThreeSpringsFarmers at gmail.com>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <c594bf25-fc4a-081e-793c-117505c8fc2f at open2learn.ca>
> Content-Type: text/plain; charset="utf-8"; Format="flowed"
> 
> Leslie,
> 
> Adding an interior air barrier will almost certainly fix the obvious 
> problem of condensation running out of the ceiling and down the walls, 
> but it's still not great building science and, unless detailed 
> meticulously, may not be enough to avoid future problems with moisture 
> damage to the roof assembly. In addition to the great GBA article that 
> you've linked to, you might want to check out this Joe Lstiburek article 
> that appeared in Fine Homebuilding a few years ago, to get a better 
> understanding of building science basics for roof ventilation:
> 
> https://buildingscience.com/sites/default/files/migrate/pdf/PA_Crash_Course_Roof_Venting_FHB.pdf
> 
> If the chosen solution is to just try to achieve a better interior air 
> seal, rather than a more robust (and expensive) solution of rebuilding 
> the roof assembly so that it is either properly vented (soffit and ridge 
> vents, with baffles the full length of the rafter bays) or uses a layer 
> of impermeable insulation to provide the air sealing and prevent 
> moisture build-up on the underside of the roof deck (e.g., 2 or 3 inches 
> of closed-cell spray foam on the underside of the roof deck), the wood 
> paneling will need to be removed from the ceiling and a good quality 
> membrane carefully installed on the underside of the rafters, prior to 
> reinstalling the t&g planks. Since you would be relying on this membrane 
> to do all the work of keeping moist air away from the cold roof deck, I 
> think you would want to use a really good membrane, like Pro Clima 
> INTELLO Plus. CertainTeed's MemBrain is another option that's likely to 
> cheaper and easier to source, but we've found that it's somewhat 
> fragile. In any case, the membrane should installed using quality 
> sealants and tapes, and as per manufacturer recommendations. When 
> reinstalling the wood finish, care will need to be taken to minimize 
> damage to the membrane. If there are too many breaches in your air 
> barrier, they may lead to decay in the roof assembly that won't show up 
> for years.
> 
> That said, I think it would be more prudent to go for a more robust 
> solution, if budget allows. Pulling the Roxul and adding an adequate 
> layer of spray foam to the underside of the roof deck would probably be 
> the cheapest and least labor-intensive solution, in this context. 
> Considering your climate and the depth of the rafter bays, it appears 
> that 2" of closed-cell spray foam would be adequate.
> 
> Jeff
> 
> 
> On 12/10/2016 9:20 PM, Leslie Moyer wrote:
>> So it sounds like you're all pretty much in agreement that an air 
>> barrier will fix the problem.  It seems to me that they have NO air 
>> barrier now--good, bad or otherwise.  I.e. they don't have 
>> penetrations in their air barrier--they don't HAVE an air barrier. 
>> The layers in the roof/ceiling assembly my friend describes below are 
>> the ENTIRETY of the construction....he listed everything in order as 
>> it is. As far as vapor movement goes, they are aware that the Roxul is 
>> not a vapor barrier and neither is the tongue and groove ceiling. I 
>> was leaning toward a "thermal bridging" problem & thought rigid foam 
>> insulation would fix it...either under the boxcar siding or under the 
>> roof sheathing.
>> 
>> There are no can lights in the ceiling.  There is wiring in place for 
>> one fixture, I believe, but no other large holes.  I'm not sure, but I 
>> don't think they have drywall under the tongue and groove boxcar 
>> siding on the ceiling--he didn't mention it below and he didn't 
>> mention it in his conversation with me earlier today.
>> 
>> This is a brand new addition--unfinished still--and they are not 
>> looking for a short-term fix. The builder just left and is willing to 
>> come back to fix the problem now, but they need to come to an 
>> agreement about what that "fix" will entail.
>> 
>> So, for a solution, they need to air seal all holes of any size that 
>> go from the sidewall plates up into the ceiling; air-seal all holes 
>> that penetrate into the ceiling. Where, exactly, should the air 
>> barrier be installed?  "The warm side" doesn't tell me enough--there 
>> are several layers on the warm side.  They need to know if they should 
>> approach this by removing the metal roofing & sheathing and go in from 
>> the top, or remove the tongue and groove siding on the ceiling and fix 
>> things from the inside-out.
>> 
>> -Leslie Moyer
>> 
>> --- obrien at hevanet.com wrote:
>> 
>> From: "Michael O'Brien" <obrien at hevanet.com>
>> To: Green Building <greenbuilding at lists.bioenergylists.org>
>> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
>> Date: Sat, 10 Dec 2016 13:38:28 -0800
>> 
>> Hi, Leslie?
>> 
>> Just wanted to chime in to agree about the air leaks across the 
>> interior side of the cathedral ceiling. Not only recessed can 
>> fixtures, but often every wiring hole drilled through top plates, 
>> every vent stack and flue have not been sealed to block air leaks. The 
>> walls may be contributing, too, if there are penetrations in the top 
>> plates.
>> 
>> The long-term fix is to take down the ceiling drywall so the leaks can 
>> be sealed and a proper vapor rertarder installed, but in the short 
>> term they could run a dehumidifier to reduce the water vapor in their 
>> occupied space.
>> 
>> Sometimes builders will open up the blocks along the eaves and install 
>> some sort of vent at or near the ridge, but this may have the effect 
>> of sending cold air under the insulation and cooling down the interior 
>> surface of the ceiling, it takes some detailing to keep the vent air 
>> above the insulation.
>> 
>> Best wishes,
>> 
>> Mike O?Brien
>> 
>> 
>> 
>> On Dec 10, 2016, at 11:50 AM, Leslie Moyer <unschooler at lrec.org 
>> <mailto:unschooler at lrec.org>> wrote:
>> 
>> I have some nearby friends having a problem. I think I understand what 
>> the problem is, and even some possible ways to solve it, but I'm not 
>> certain I could give them advice that would fix their problem the best 
>> or cheapest way. I thought you guys could, though!
>> 
>> They read this article & I think they will go ahead and pay to read 
>> the article referenced within it:
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral 
>> ceiling. We live in northeastern Oklahoma (zone 3) and just added a 
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was 
>> just opened up to the main house earlier this week, and we got hit 
>> with (what are for us) very cold temperatures.  Thursday night had a 
>> low of 12 F.  By noon on Friday we noticed that water was dripping 
>> down the north side interior wall  (along the drywall).  The drip 
>> lines appeared to be spaced every 24 inches, or about where a roof 
>> rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and 
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  
>> The interior ceiling is wooden tongue and groove car siding.   The 
>> roof decking is LP TechShield Radiant Barrier (with the metal foil 
>> side facing the interior of the house, as described on the boards) 
>> with a metal roof (there is felt paper in between the decking and the 
>> metal roof on the North side, but on the South side we used double 
>> bubble).  We did not have any condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re 
>> getting as many different suggested solutions.  We are desperate to 
>> fix this problem and would greatly appreciate any help!  Thank you!
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org <mailto:Greenbuilding at bioenergylists.org>
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>> 
>> _______________________________________________ Greenbuilding mailing 
>> list to Send a Message to the list, use the email address 
>> Greenbuilding at bioenergylists.org 
>> </eonapps/ft/wm/page/compose?send_to=Greenbuilding%40bioenergylists.org> 
>> to UNSUBSCRIBE or Change your List Settings use the web page 
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>> 
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
> 
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> 
> ------------------------------
> 
> Message: 9
> Date: Sun, 11 Dec 2016 11:29:21 -0500
> From: Norbert Senf <norbert.senf at gmail.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID:
> 	<CAGYvK4cQqvmQb3nPhuPeX6kKi1ShsiwirpdVCfqN_mtypGzhkw at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Here's one way:
> 
> - strip off the tongue and groove.
> - Add a vapor barrier (6 mil poly). Research the proper details to seal the
> joints in the plastic. Here they use acoustical sealant.
> - a good way to handle wiring, etc. is to put 2x2 strapping on top, to
> provide a chase so you don't have to penetrate the plastic. It also avoids
> a gazillion nail holes in the plastic from the tongue and groove. The real
> pros will use acoustical sealant where the strapping is nailed to the
> rafters.
> - pay particular attention to all the edge details.
> 
> There is another approach I have seen, which is airtight drywall. You need
> foil backed drywall, plus gaskets. I believe it was developed at the
> University of Illinois................Norbert
> 
> On Sat, Dec 10, 2016 at 9:20 PM, Leslie Moyer <unschooler at lrec.org> wrote:
> 
>> So it sounds like you're all pretty much in agreement that an air barrier
>> will fix the problem.  It seems to me that they have NO air barrier
>> now--good, bad or otherwise.  I.e. they don't have penetrations in their
>> air barrier--they don't HAVE an air barrier.  The layers in the
>> roof/ceiling assembly my friend describes below are the ENTIRETY of the
>> construction....he listed everything in order as it is. As far as vapor
>> movement goes, they are aware that the Roxul is not a vapor barrier and
>> neither is the tongue and groove ceiling. I was leaning toward a "thermal
>> bridging" problem & thought rigid foam insulation would fix it...either
>> under the boxcar siding or under the roof sheathing.
>> 
>> There are no can lights in the ceiling.  There is wiring in place for one
>> fixture, I believe, but no other large holes.  I'm not sure, but I don't
>> think they have drywall under the tongue and groove boxcar siding on the
>> ceiling--he didn't mention it below and he didn't mention it in his
>> conversation with me earlier today.
>> 
>> This is a brand new addition--unfinished still--and they are not looking
>> for a short-term fix. The builder just left and is willing to come back to
>> fix the problem now, but they need to come to an agreement about what that
>> "fix" will entail.
>> 
>> So, for a solution, they need to air seal all holes of any size that go
>> from the sidewall plates up into the ceiling; air-seal all holes that
>> penetrate into the ceiling. Where, exactly, should the air barrier be
>> installed?  "The warm side" doesn't tell me enough--there are several
>> layers on the warm side.  They need to know if they should approach this by
>> removing the metal roofing & sheathing and go in from the top, or remove
>> the tongue and groove siding on the ceiling and fix things from the
>> inside-out.
>> 
>> -Leslie Moyer
>> 
>> --- obrien at hevanet.com wrote:
>> 
>> From: "Michael O'Brien" <obrien at hevanet.com>
>> To: Green Building <greenbuilding at lists.bioenergylists.org>
>> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
>> Date: Sat, 10 Dec 2016 13:38:28 -0800
>> 
>> Hi, Leslie?
>> 
>> Just wanted to chime in to agree about the air leaks across the interior
>> side of the cathedral ceiling. Not only recessed can fixtures, but often
>> every wiring hole drilled through top plates, every vent stack and flue
>> have not been sealed to block air leaks. The walls may be contributing,
>> too, if there are penetrations in the top plates.
>> 
>> The long-term fix is to take down the ceiling drywall so the leaks can be
>> sealed and a proper vapor rertarder installed, but in the short term they
>> could run a dehumidifier to reduce the water vapor in their occupied space.
>> 
>> Sometimes builders will open up the blocks along the eaves and install
>> some sort of vent at or near the ridge, but this may have the effect of
>> sending cold air under the insulation and cooling down the interior surface
>> of the ceiling, it takes some detailing to keep the vent air above the
>> insulation.
>> 
>> Best wishes,
>> 
>> Mike O?Brien
>> 
>> 
>> 
>> On Dec 10, 2016, at 11:50 AM, Leslie Moyer <unschooler at lrec.org> wrote:
>> 
>> I have some nearby friends having a problem. I think I understand what the
>> problem is, and even some possible ways to solve it, but I'm not certain I
>> could give them advice that would fix their problem the best or cheapest
>> way. I thought you guys could, though!
>> 
>> They read this article & I think they will go ahead and pay to read the
>> article referenced within it:
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-
>> insulated-cathedral-ceiling
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral
>> ceiling.  We live in northeastern Oklahoma (zone 3) and just added a
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just
>> opened up to the main house earlier this week, and we got hit with (what
>> are for us) very cold temperatures.  Thursday night had a low of 12 F.  By
>> noon on Friday we noticed that water was dripping down the north side
>> interior wall  (along the drywall).  The drip lines appeared to be spaced
>> every 24 inches, or about where a roof rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  The
>> interior ceiling is wooden tongue and groove car siding.   The roof decking
>> is LP TechShield Radiant Barrier (with the metal foil side facing the
>> interior of the house, as described on the boards) with a metal roof (there
>> is felt paper in between the decking and the metal roof on the North side,
>> but on the South side we used double bubble).   We did not have any
>> condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re getting
>> as many different suggested solutions.  We are desperate to fix this
>> problem and would greatly appreciate any help!  Thank you!
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
>> _______________________________________________ Greenbuilding mailing
>> list to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> <http:///eonapps/ft/wm/page/compose?send_to=Greenbuilding%40bioenergylists.org>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
> 
> 
> 
> -- 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Qu?bec J0X 2Y0
> 819.647.5092
> www.heatkit.com
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> 
> ------------------------------
> 
> Message: 10
> Date: Sun, 11 Dec 2016 08:50:20 -0800
> From: Reuben Deumling <9watts at gmail.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID:
> 	<CAE5fceA-UpxK9xKXw-jHaRxs0aiFGZ4dKG7uXjrBpaJyPwza1A at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Lstiburek rocks. Thank you for that article, Jeff.
> 
> On Sun, Dec 11, 2016 at 7:58 AM, Jeff Martin <jeff at open2learn.ca> wrote:
> 
>> Leslie,
>> 
>> Adding an interior air barrier will almost certainly fix the obvious
>> problem of condensation running out of the ceiling and down the walls, but
>> it's still not great building science and, unless detailed meticulously,
>> may not be enough to avoid future problems with moisture damage to the roof
>> assembly. In addition to the great GBA article that you've linked to, you
>> might want to check out this Joe Lstiburek article that appeared in Fine
>> Homebuilding a few years ago, to get a better understanding of building
>> science basics for roof ventilation:
>> 
>> https://buildingscience.com/sites/default/files/migrate/
>> pdf/PA_Crash_Course_Roof_Venting_FHB.pdf
>> 
>> If the chosen solution is to just try to achieve a better interior air
>> seal, rather than a more robust (and expensive) solution of rebuilding the
>> roof assembly so that it is either properly vented (soffit and ridge vents,
>> with baffles the full length of the rafter bays) or uses a layer of
>> impermeable insulation to provide the air sealing and prevent moisture
>> build-up on the underside of the roof deck (e.g., 2 or 3 inches of
>> closed-cell spray foam on the underside of the roof deck), the wood
>> paneling will need to be removed from the ceiling and a good quality
>> membrane carefully installed on the underside of the rafters, prior to
>> reinstalling the t&g planks. Since you would be relying on this membrane to
>> do all the work of keeping moist air away from the cold roof deck, I think
>> you would want to use a really good membrane, like Pro Clima INTELLO Plus.
>> CertainTeed's MemBrain is another option that's likely to cheaper and
>> easier to source, but we've found that it's somewhat fragile. In any case,
>> the membrane should installed using quality sealants and tapes, and as per
>> manufacturer recommendations. When reinstalling the wood finish, care will
>> need to be taken to minimize damage to the membrane. If there are too many
>> breaches in your air barrier, they may lead to decay in the roof assembly
>> that won't show up for years.
>> 
>> That said, I think it would be more prudent to go for a more robust
>> solution, if budget allows. Pulling the Roxul and adding an adequate layer
>> of spray foam to the underside of the roof deck would probably be the
>> cheapest and least labor-intensive solution, in this context. Considering
>> your climate and the depth of the rafter bays, it appears that 2" of
>> closed-cell spray foam would be adequate.
>> 
>> Jeff
>> 
>> On 12/10/2016 9:20 PM, Leslie Moyer wrote:
>> 
>> So it sounds like you're all pretty much in agreement that an air barrier
>> will fix the problem.  It seems to me that they have NO air barrier
>> now--good, bad or otherwise.  I.e. they don't have penetrations in their
>> air barrier--they don't HAVE an air barrier.  The layers in the
>> roof/ceiling assembly my friend describes below are the ENTIRETY of the
>> construction....he listed everything in order as it is. As far as vapor
>> movement goes, they are aware that the Roxul is not a vapor barrier and
>> neither is the tongue and groove ceiling. I was leaning toward a "thermal
>> bridging" problem & thought rigid foam insulation would fix it...either
>> under the boxcar siding or under the roof sheathing.
>> 
>> There are no can lights in the ceiling.  There is wiring in place for one
>> fixture, I believe, but no other large holes.  I'm not sure, but I don't
>> think they have drywall under the tongue and groove boxcar siding on the
>> ceiling--he didn't mention it below and he didn't mention it in his
>> conversation with me earlier today.
>> 
>> This is a brand new addition--unfinished still--and they are not looking
>> for a short-term fix. The builder just left and is willing to come back to
>> fix the problem now, but they need to come to an agreement about what that
>> "fix" will entail.
>> 
>> So, for a solution, they need to air seal all holes of any size that go
>> from the sidewall plates up into the ceiling; air-seal all holes that
>> penetrate into the ceiling. Where, exactly, should the air barrier be
>> installed?  "The warm side" doesn't tell me enough--there are several
>> layers on the warm side.  They need to know if they should approach this by
>> removing the metal roofing & sheathing and go in from the top, or remove
>> the tongue and groove siding on the ceiling and fix things from the
>> inside-out.
>> 
>> -Leslie Moyer
>> 
>> --- obrien at hevanet.com wrote:
>> 
>> From: "Michael O'Brien" <obrien at hevanet.com> <obrien at hevanet.com>
>> To: Green Building <greenbuilding at lists.bioenergylists.org>
>> <greenbuilding at lists.bioenergylists.org>
>> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
>> Date: Sat, 10 Dec 2016 13:38:28 -0800
>> 
>> Hi, Leslie?
>> 
>> Just wanted to chime in to agree about the air leaks across the interior
>> side of the cathedral ceiling. Not only recessed can fixtures, but often
>> every wiring hole drilled through top plates, every vent stack and flue
>> have not been sealed to block air leaks. The walls may be contributing,
>> too, if there are penetrations in the top plates.
>> 
>> The long-term fix is to take down the ceiling drywall so the leaks can be
>> sealed and a proper vapor rertarder installed, but in the short term they
>> could run a dehumidifier to reduce the water vapor in their occupied space.
>> 
>> Sometimes builders will open up the blocks along the eaves and install
>> some sort of vent at or near the ridge, but this may have the effect of
>> sending cold air under the insulation and cooling down the interior surface
>> of the ceiling, it takes some detailing to keep the vent air above the
>> insulation.
>> 
>> Best wishes,
>> 
>> Mike O?Brien
>> 
>> 
>> 
>> On Dec 10, 2016, at 11:50 AM, Leslie Moyer <unschooler at lrec.org> wrote:
>> 
>> I have some nearby friends having a problem. I think I understand what the
>> problem is, and even some possible ways to solve it, but I'm not certain I
>> could give them advice that would fix their problem the best or cheapest
>> way. I thought you guys could, though!
>> 
>> They read this article & I think they will go ahead and pay to read the
>> article referenced within it:
>> 
>> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-
>> insulated-cathedral-ceiling
>> 
>> We are considered a "hot humid" climate--NE Oklahoma
>> ???????????.
>> 
>> We have a question regarding condensation problems in a cathedral
>> ceiling.  We live in northeastern Oklahoma (zone 3) and just added a
>> dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just
>> opened up to the main house earlier this week, and we got hit with (what
>> are for us) very cold temperatures.  Thursday night had a low of 12 F.  By
>> noon on Friday we noticed that water was dripping down the north side
>> interior wall  (along the drywall).  The drip lines appeared to be spaced
>> every 24 inches, or about where a roof rafter would be.
>> 
>> The ceiling/roof construction was constructed with 2 x 8 rafters and
>> insulated with R30 Roxul (rock wool) insulation and is not vented.  The
>> interior ceiling is wooden tongue and groove car siding.   The roof decking
>> is LP TechShield Radiant Barrier (with the metal foil side facing the
>> interior of the house, as described on the boards) with a metal roof (there
>> is felt paper in between the decking and the metal roof on the North side,
>> but on the South side we used double bubble).   We did not have any
>> condensation issues on the south wall.
>> 
>> We have spoken with over half a dozen different experts, and we?re getting
>> as many different suggested solutions.  We are desperate to fix this
>> problem and would greatly appreciate any help!  Thank you!
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
>> _______________________________________________ Greenbuilding mailing
>> list to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> <http:///eonapps/ft/wm/page/compose?send_to=Greenbuilding%40bioenergylists.org>
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email addressGreenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web pagehttp://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.bioenergylists.org
>> 
>> 
>> 
>> _______________________________________________
>> Greenbuilding mailing list
>> to Send a Message to the list, use the email address
>> Greenbuilding at bioenergylists.org
>> 
>> to UNSUBSCRIBE or Change your List Settings use the web page
>> http://lists.bioenergylists.org/mailman/listinfo/greenbuilding_lists.
>> bioenergylists.org
>> 
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> 
> ------------------------------
> 
> Message: 11
> Date: Sun, 11 Dec 2016 09:19:05 -0800
> From: "Michael O'Brien" <obrien at hevanet.com>
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Message-ID: <B50D5E83-4BAA-4A56-9F9A-6055338C9E60 at hevanet.com>
> Content-Type: text/plain; charset="utf-8"
> 
> Hi, guys?
> 
> Airtight drywall or ADA was originally based on an idea of Gus Handegord?s that was first implemented by Joe Lstiburek and his partner at the time. Their first trials used plywood to bridge between drywall sheets in back of framing junctions, and an acoustical sealant to seal drywall to framing. Since then it has developed into several different versions, but I would give them credit for starting it way back in the ancient 1980s. 
> 
> Best,
> 
> Mike O'Brien
> 
> 
> On Dec 11, 2016, at 8:29 AM, Norbert Senf <norbert.senf at gmail.com> wrote:
> 
> Here's one way:
> 
> - strip off the tongue and groove.
> - Add a vapor barrier (6 mil poly). Research the proper details to seal the joints in the plastic. Here they use acoustical sealant. 
> - a good way to handle wiring, etc. is to put 2x2 strapping on top, to provide a chase so you don't have to penetrate the plastic. It also avoids a gazillion nail holes in the plastic from the tongue and groove. The real pros will use acoustical sealant where the strapping is nailed to the rafters.
> - pay particular attention to all the edge details.
> 
> There is another approach I have seen, which is airtight drywall. You need foil backed drywall, plus gaskets. I believe it was developed at the University of Illinois................Norbert
> 
> On Sat, Dec 10, 2016 at 9:20 PM, Leslie Moyer <unschooler at lrec.org <mailto:unschooler at lrec.org>> wrote:
> So it sounds like you're all pretty much in agreement that an air barrier will fix the problem.  It seems to me that they have NO air barrier now--good, bad or otherwise.  I.e. they don't have penetrations in their air barrier--they don't HAVE an air barrier.  The layers in the roof/ceiling assembly my friend describes below are the ENTIRETY of the construction....he listed everything in order as it is. As far as vapor movement goes, they are aware that the Roxul is not a vapor barrier and neither is the tongue and groove ceiling. I was leaning toward a "thermal bridging" problem & thought rigid foam insulation would fix it...either under the boxcar siding or under the roof sheathing. 
> 
> There are no can lights in the ceiling.  There is wiring in place for one fixture, I believe, but no other large holes.  I'm not sure, but I don't think they have drywall under the tongue and groove boxcar siding on the ceiling--he didn't mention it below and he didn't mention it in his conversation with me earlier today.
> 
> This is a brand new addition--unfinished still--and they are not looking for a short-term fix. The builder just left and is willing to come back to fix the problem now, but they need to come to an agreement about what that "fix" will entail.  
> 
> So, for a solution, they need to air seal all holes of any size that go from the sidewall plates up into the ceiling; air-seal all holes that penetrate into the ceiling. Where, exactly, should the air barrier be installed?  "The warm side" doesn't tell me enough--there are several layers on the warm side.  They need to know if they should approach this by removing the metal roofing & sheathing and go in from the top, or remove the tongue and groove siding on the ceiling and fix things from the inside-out.  
> 
> -Leslie Moyer
> 
> --- obrien at hevanet.com <mailto:obrien at hevanet.com> wrote:
> 
> From: "Michael O'Brien" <obrien at hevanet.com <mailto:obrien at hevanet.com>>
> To: Green Building <greenbuilding at lists.bioenergylists.org <mailto:greenbuilding at lists.bioenergylists.org>>
> Subject: Re: [Greenbuilding] Unvented cathedral ceiling condensation
> Date: Sat, 10 Dec 2016 13:38:28 -0800
> 
> Hi, Leslie?
> 
> Just wanted to chime in to agree about the air leaks across the interior side of the cathedral ceiling. Not only recessed can fixtures, but often every wiring hole drilled through top plates, every vent stack and flue have not been sealed to block air leaks. The walls may be contributing, too, if there are penetrations in the top plates. 
> 
> The long-term fix is to take down the ceiling drywall so the leaks can be sealed and a proper vapor rertarder installed, but in the short term they could run a dehumidifier to reduce the water vapor in their occupied space. 
> 
> Sometimes builders will open up the blocks along the eaves and install some sort of vent at or near the ridge, but this may have the effect of sending cold air under the insulation and cooling down the interior surface of the ceiling, it takes some detailing to keep the vent air above the insulation.
> 
> Best wishes,
> 
> Mike O?Brien
> 
> 
> 
> On Dec 10, 2016, at 11:50 AM, Leslie Moyer <unschooler at lrec.org <mailto:unschooler at lrec.org>> wrote:
> 
> I have some nearby friends having a problem. I think I understand what the problem is, and even some possible ways to solve it, but I'm not certain I could give them advice that would fix their problem the best or cheapest way. I thought you guys could, though!  
> 
> They read this article & I think they will go ahead and pay to read the article referenced within it: 
> 
> http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling <http://www.greenbuildingadvisor.com/blogs/dept/musings/how-build-insulated-cathedral-ceiling>
> 
> We are considered a "hot humid" climate--NE Oklahoma 
> ???????????.
> 
> We have a question regarding condensation problems in a cathedral ceiling.  We live in northeastern Oklahoma (zone 3) and just added a dinning room (cathedral ceiling) 15 x 19 addition.  The addition was just opened up to the main house earlier this week, and we got hit with (what are for us) very cold temperatures.  Thursday night had a low of 12 F.  By noon on Friday we noticed that water was dripping down the north side interior wall  (along the drywall).  The drip lines appeared to be spaced every 24 inches, or about where a roof rafter would be.
> 
> The ceiling/roof construction was constructed with 2 x 8 rafters and insulated with R30 Roxul (rock wool) insulation and is not vented.  The interior ceiling is wooden tongue and groove car siding.   The roof decking is LP TechShield Radiant Barrier (with the metal foil side facing the interior of the house, as described on the boards) with a metal roof (there is felt paper in between the decking and the metal roof on the North side, but on the South side we used double bubble).   We did not have any condensation issues on the south wall.
> 
> We have spoken with over half a dozen different experts, and we?re getting as many different suggested solutions.  We are desperate to fix this problem and would greatly appreciate any help!  Thank you!
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> 
> -- 
> Norbert Senf
> Masonry Stove Builders
> 25 Brouse Road, RR 5
> Shawville Qu?bec J0X 2Y0
> 819.647.5092
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