Should the Paper Facing of Batt Insulation Face the Inside or Outside?

first_imgWhat about the advice to put it on the “warm-in-winter” side?If that really mattered, do you think the U.S. building code would have dropped the requirement to use paper-faced batts? The warm-in-winter suggestion says that if you’re trying to limit the diffusion of water vapor, put the vapor retarder on the humid side of the wall, where … uh … it’s not able to retard much vapor.In a really, really cold climate, it may matter, but even in Maine and Ontario, vapor retarder paint would be a better way to go. If you want to slow down the vapor diffusion, why not do it before it hits the drywall?So just relax. If your building inspector wants you to put the kraft paper on the “wrong” side, take another look at the graph above and be comforted that it doesn’t really matter. Then go get yourself some unfaced batts (and do your best to install them to Grade I quality).~~~~~~~~~~~~~~~* Speaking of fiberglass batt insulation, Carl Seville (a.k.a. the Green Curmudgeon) wrote another article on poorly installed batts recently, with photos of Knauf fiberglass. Rather than being a bully, like Guardian did to me a couple of years ago, they commented on the article and asked for a dialogue on how to get better installation in the field. Kudos to Knauf!† My friend Abe Kruger likes to say that you should treat building inspectors like wild animals. You have to approach slowly and quietly because they spook easily. In the HERS rater class I taught in Toronto this week, I used that analogy but before I could get to the reason why they’re like wild animals, one of the students said, “You mean we can shoot them?” Why doesn’t it matter?First, the kraft paper is a vapor retarder meant to reduce the potential for moisture problems caused by diffusion. That sounds like a good idea, but the vast majority of moisture problems are caused by air leakage, not diffusion, even in places like Maine. Do the air sealing; stop worrying so much about vapor retarders. Second, if you install it the wrong way, it’s unlikely that you’ll have a problem. I suggest you read Joseph Lstiburek’s paper, Mind the Gap, Eh! The graph below, from that paper, shows the water vapor permeance of kraft paper as a function of relative humidity.As you can see, the permeance of the kraft paper rises as the relative humidity rises and hits 10, the point at which we describe a material as vapor permeable, when the RH is 60%. The upshot here is that if you put the kraft paper on the wrong side and it gets wet, it won’t trap moisture. The wetter it gets, the better it dries. If you put it on the right side, where the humidity is, it’s not much of a vapor retarder, because that’s where it becomes vapor-permeable.Also on the graph is the permeance of polyethylene. As Dr. Joe says in the article, “Plastic vapor barriers really are vapor barriers when things get wet. Not so asphalt-saturated kraft paper. And most walls with asphalt-saturated kraft paper thank the building science gods for the difference.” RELATED ARTICLES Do I Need a Vapor Retarder?Vapor Retarders and Vapor BarriersForget Vapor Diffusion — Stop the Air Leaks!When Sunshine Drives Moisture Into WallsQuestions and Answers About Air BarriersQ&A Spotlight: Vapor Barriers Redux Joe Lstiburek Discusses Basement Insulation and Vapor RetardersJoseph Lstiburek: Air Barrier or Vapor Barrier?center_img If you install fiberglass batt insulation* with a kraft paper vapor retarder in a home, which way do you face the vapor retarder? To the inside of the home or the outside of the home? For many building science questions, the answer is, “It depends.” For this one, however, the answer is clear.SPOILER ALERT: The answer is in the next paragraph — so if you’d rather wait and find out when you see the movie in the theater, don’t read any further.The answer is: It doesn’t matter. Nope. You can install the paper facing however you want — as long as the building inspector† lets you, of course. Allison Bailes of Decatur, Georgia, is a speaker, writer, energy consultant, RESNET-certified trainer, and the author of the Energy Vanguard Blog. You can follow him on Twitter at @EnergyVanguard.last_img read more

Ebondo drops 31 as CEU holds off Marinerong Pilipino

first_imgBrace for potentially devastating typhoon approaching PH – NDRRMC MOST READ PBA IMAGESCentro Escolar University rode Rod Ebondo’s big performance to kickstart its campaign with a 104-93 win over Marinerong Pilipino in the 2018 PBA D-League Aspirants’ Cup Monday at Ynares Sports Arena in Pasig.Ebondo flirted with a double-double, posting 31 points and nine rebounds.ADVERTISEMENT NEXT BLOCK ASIA 2.0 introduces GURUS AWARDS to recognize and reward industry influencers 2 ‘newbie’ drug pushers fall in Lucena sting Don’t miss out on the latest news and information. LATEST STORIES CEU 104 — Ebondo 31, Fuentes 20, Manlangit 19, Wamar 11, Arim 9, Guinitaran 8, Cruz 4, Aquino 2, Caballero 0, Intic 0, Saber 0, Veron 0.MARINERONG PILIPINO 93 — Ayonayon 24, Subido 17, Robles 17, Toth 10, Tratter 6, Iñigo 6, Paredes 6, Banal 5, Pasaol 2, Babilonia 0, Lopez 0, Terso 0.Quarters: 20-21, 55-41, 83-75, 104-93. Kammuri turning to super typhoon less likely but possible — Pagasa Philippines marks anniversary of massacre with calls for justice PLAY LIST 01:44Philippines marks anniversary of massacre with calls for justice01:27Filipino athletes get grand send-off ahead of SEA Games01:29DOH kicks off nationwide polio vaccination drive01:29Police teams find crossbows, bows in HK university01:35Panelo suggests discounted SEA Games tickets for students02:49Robredo: True leaders perform well despite having ‘uninspiring’ boss02:42PH underwater hockey team aims to make waves in SEA Games01:19Fire erupts in Barangay Tatalon in Quezon City Slow and steady hope for near-extinct Bangladesh tortoises John Lloyd Cruz a dashing guest at Vhong Navarro’s wedding The Congolese, however, wasn’t the lone hero for the Scorpions as Judel Fuentes went 3-of-8 from three to finish with 20 markers, five of which coming in the last 1:22 to stave off the late uprising from the Skippers.Joseph Manlangit also got eight of his 19 points in the payoff period, and had seven rebounds, while Orlan Wamar tallied 11 markers, four rebounds, and three dimes.FEATURED STORIESSPORTSWATCH: Drones light up sky in final leg of SEA Games torch runSPORTSLillard, Anthony lead Blazers over ThunderSPORTSMalditas save PH from shutoutCEU saw its 19-point lead, 62-43, dissipate as Marinerong Pilipino rallied back to knot the score at 75 late in the third quarter.But the Scorpions quickly restored order, ending the third frame on an 8-0 run to regain the upperhand. Globe Business launches leading cloud-enabled and hardware-agnostic conferencing platform in PH CEU was also buoyed by its 12-of-30 sniping from three while lording the boards, 55-44.“It’s all credit to the players. They gave their best,” said coach Yong Garcia. “We had a good first half, but in the third quarter, we relaxed. I’m just glad that we followed the gameplan and recovered in the fourth.”Marinerong Pilipino stumbled to its second straight defeat and dropped to 1-2.Rian Ayonayon captained the Skippers with 24 points, eight rebounds, and two assists, while Renzo Subido and Billy Robles both got 17.The Scores:ADVERTISEMENT Read Next Typhoon Kammuri accelerates, gains strength en route to PH View comments Former champ Francisco loses to Ortega in Mexicolast_img read more