How to Vent a Rainscreen

first_imgWhere the vents should beAccording to Taylor, rainscreens that are vented at both the top and the bottom work better, although it’s not clear whether the top vent actually adds much in the way of performance.“With one only vented at the bottom you get a capillary break, a drainage gap to handle bulk water intrusion, and some drying,” Taylor says. “Here in the wet Pacific Northwest almost all are only vented that way, and they perform very well. In a less damp climate, with a wall assembly that isn’t risky, venting at the top probably doesn’t bring huge benefits.”Tyler Leclear Vachta cites research in British Columbia on the benefit of vented rainscreens, but he doesn’t necessarily see any added benefit to linking a rainscreen and attic ventilation.“We most commonly see a small vent space just below the soffit, protected from wind-driven rain by a trim board and protected against insects by back wrapping the rainscreen fabric,” Vachta says. “There is certainly no benefit to your attic to have the two systems connected.”The connection, Pehl replies, is a matter of convenience as well as appearance.“The ideal case is to vent the rainscreen into the soffit because it’s the easiest assembly at this point in construction,” he says. “It also supports the aesthetics we want, although venting to the exterior at the top of the cladding as you describe might not even be a noticeable detail change.“The real benefit to connecting the two systems is simplicity of the assembly, and the aesthetics of eliminating the venting channel in the soffit,” he continues. “To be clear, in the assembly that we are now considering, attic venting, for code and whatever benefit it does provide, is provided through from the bottom of the cladding, through a bug screen at the bottom of the 3/4-inch rainscreen channels, up to the soffit at the top, through the vent chutes into the attic, out the ridge vent at the top of the roof.” GBA senior editor Martin Holladay notes fire safety is a question that’s been raised before (see, for example, “Can a rainscreen become a chimney for fire?” and “Fire-resistant rainscreen system”). “The issue of fire safety is contentious,” he says, “but in some areas of North America — areas where wildfires are common — vented rainscreens of any kind are controversial.”He also notes that if the house has an effective ceiling air barrier, attic venting doesn’t matter much (see “All About Attic Venting”).John Clark cites an article on this topic by Joseph Lstiburek of the Building Science Corporation. In it, he discusses the Grenfell Tower fire in London, exacerbated by rainscreen details that included a large air gap of 2 inches and a combustible outer skin. The bottom line is that air gaps don’t have to be all that big.“We have addressed the gap many times before with respect to drainage,” Lstiburek wrote. “We want to control hydrostatic pressure and pretty much call it a day. We do not need much of a gap to control hydrostatic pressure…. a continuous 1/32 to 1/16 of an inch is all that you need.”When the air gap is as big as it was in London, the fire implications are “huge,” but when the air gaps is small, less than 3/4 inch, “the friction from both surfaces bounding the air gap limits the air flow,” Lstiburek writes. “The boundary layer on both surfaces is an effective fire stop.”In other words, in this assembly fire dangers are a non-issue. Our expert’s opinionPeter Yost, GBA’s technical director, added this:Fire safety and vented rainscreens: The Institute for Business and Home Safety (IBHS) recommends the use of 1/8-inch mesh screening, robust enough to keep embers and brands from getting into any vented space on the building exterior. For more information, see “Top 10 Ways to Protect Your Property from Wildfire.”On a residential project in Portola Valley, California — in a very wildfire-prone area — we vented the rainscreen cladding top and bottom using not only 1/8-inch mesh but also an intumescent paint (painted onto the wire mesh) that would foam and close off the top and bottom openings of the rainscreen when activated by high heat (that is, in the event of a wildfire). We developed this approach based on conversations and advice from Steve Quarles, a leading wildfire expert who is now Chief Scientist for Wildfire and Durabilty at the IBHS Research Center.Closing off the top of a vented rainscreen wall assembly: I have seen projects taking this approach with the paint peeling off the top course or two of lapped siding because warm, moisture-laden and buoyant air is “stacking up” in the closed-off vented area. (Some folks call it a “vented” assembly when the top is closed and a “ventilated” assembly when top and bottom are open, with the former not supporting convective drying while the latter does.) Whether you close the top to prevent moisture from getting in (wind-driven rain) or open it to let moisture out (solar-driven heating of cladding in hot-humid conditions) may be based on your own experience, climate, and site conditions.And yes, the depth of the vented space does make a difference. In British Columbia, codes mandate a 10 millimeter (about 3/8-inch) space between the cladding and the rest of the wall, choosing this as a minimum depth to promote 100% free drainage and air movement.Rainscreen products like HydroGap that create a 1-mm gap between the cladding and the rest of the wall pass the ASTIM drainage test minimum of 90% free drainage. That said, the manufacturer of HydroGap readily admits that a 1-mm gap, regardless of whether it is open on the top and bottom, does not support convective air movement.Connecting ventilated wall claddings to soffit-to-ridge venting: I don’t believe that any U.S. code addresses this issue but plenty of building code inspectors will have their own perspective or position. I have asked Joe Lstiburek about this, as well as asked a bunch of builders who take this approach, and have not heard any negative reports, if you limit this connection to the movement of outside air and not any air leaking at eaves. In other words, with a continuous air barrier at the eaves, connecting wall and roof venting just gives you a taller, longer column of warm air, and hence more stack effect to drive air movement.For a look at how I handled the rainscreen on my own home, see Images #2 and #3 below. A vented rainscreen — an air gap behind the siding — has become a standard detail in many new houses. It helps remove moisture that works its way through the siding, and in the process helps siding last longer. It’s the “vented” part of this equation that has Gerald Pehl thinking.“I’ve got an assembly design for a vented rainscreen, and it will be held continuous to the soffit spaces, which then vent through to the attic ridge vent via conventional vent chutes between the rafters,” Pehl says in a comment posted in the Q&A forum at GBA.His question, and the start of this Q&A Spotlight, is whether this plan eliminates the need for additional soffit venting. Pehl’s building inspector has left the decision up to him. All About Attic VentingAll About RainscreensLstiburek’s Rules for Venting RoofsAll About Wall RotWhat’s the Best Approach for a Rainscreen?Video: Vented Rainscreen Siding Assemblies Great Fire of London Are outdoor temperatures a factor?Ambient temperatures may play a part in whether elevated moisture levels in walls lead to mold growth or rot, Vachta suggests. While a 15% wood moisture equivalent is perfect for fungal growth, he says, a WME of more than 20% is ideal for rot.“During the cold winter months those thresholds aren’t as important because the freezing cold inhibits rot and fungus,” he says.Low temperatures also remove moisture from the air, Pehl says, adding that “may be at least as important as the cold temperature in preventing mold/rot. I’ve been told that in the coldest months in Minnesota it’s as dry as the driest desert.”“Yes, being a Minnesotan myself I can attest to the dry winter air!” Vachta says. “Cold air simply can’t hold as much moisture, true, but does that have a drying effect on the wood? Air/ temperature/ water move from high pressure/ temperature/ concentration to low pressure temperature/ concentration. The moisture in the wood runs the risk of condensing, or frosting. In a roundabout way, I suppose frosting (like freezer-burn) is drying.”In Taylor’s neck of the woods, temperatures don’t get cold enough to offer that kind of winter protection from mold, but there’s no doubt that rainscreens have been a very significant improvement in building.“Including rainscreens in our construction practices has transformed the resilience of walls here,” he says. “I simply don’t see the problems now that were endemic in any building I went to renovate in the past.” RELATED ARTICLES Risks in the event of a fireMalcolm Taylor suggests that connecting the rainscreen and attic ventilation might increase the drying potential of the wall assembly. He points out, however, that a rainscreen is typically 1/2 inch to 3/4 inch deep, a function of what material is used to create it, and that probably isn’t enough to make up the required area for soffit vents. Even if it did, he adds, that detail raises another issue: What happens in the event of a fire?“Here in Canada,” Taylor writes, “we can’t connect the two to find out. The code precludes it because it creates a concealed air space from which fire can spread up into the roof assembly. Practically, I wonder how much difference there is from a fire spread point of view between a connected rainscreen, and one which is vented at the top with soffit vents immediately above. I’ll be interested to see what other posters think.” Connecting rainscreen and attic may encourage moldTaylor notes that while Building Science Corporation has made the point that a very small air gap is effective behind a rainscreen, “the reality of construction is that they may become closed due to the WRB [water-resistive barrier] intruding into them, or wood shrinkage over time.”He also finds a couple of points worth repeating in the British Columbia study that Vachta has cited. First, a well-ventilated rainscreen works better than a poorly ventilated one. More important, the study “expressly suggests” that connecting the rainscreen to the attic is a lousy idea because of the moisture and mold problems that occur in buildings where this was done.“Whether these problems are likely to occur outside the Pacific Northwest is still an open question,” Taylor writes. “Things happen in our climate that simply don’t elsewhere. The plywood roof sheathing in a well air-sealed and ventilated attic can grow mold, as can the cladding on the north side of houses. You may be building in more forgiving circumstances than we encounter here.”Taylor’s remarks about the danger of a small rainscreen gap becoming blocked are well taken, Vachta says.“Textured WRBs that create the smallest gap also have the least room for error,” he writes. “Rainscreen meshes also compress significantly, both impeding the drainage/ventilation gap and resulting in an uneven work surface. You want to be sure the rainscreen maintains a cavity during installation and the life of your building.”The real risk to moisture-sensitive materials, he adds, is not from a one-time soaking, but from chronic exposure to small amounts of moisture.“Drying with ventilation is the best way to address that,” he says. “One aspect of this [British Columbia] study that was unique is that it looked at the walls over a long period of time. There are a lot of studies and testing that just look at how walls perform under a single ASTM test where they have to drain 90% of the liquid moisture poured at the top of the assembly, or identify points where water under pressure comes spraying through the wall.“But how long does it take the rest of that moisture to get out of the wall?” he continues. “Which layers get wet in the process? And what if the next moisture event happens before the wall dries?”last_img read more

Turkey seeks jail term for Enes Kanter for insulting Erdogan

first_imgDo not bring these items in SEA Games venues Police teams find crossbows, bows in HK university PLAY LIST 01:29Police 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 Games01:44Philippines marks anniversary of massacre with calls for justice01:19Fire erupts in Barangay Tatalon in Quezon City Typhoon Kammuri accelerates, gains strength en route to PH Ravena shines as NLEX survives KIA; Magnolia rips Alaska The player is a vocal supporter of Fethullah Gulen, the U.S.-based cleric blamed by Turkey for last year’s failed military coup.Kanter was detained in Romania on May 20. He said he was able to return to the United States after American officials intervened.He said his family remains in Turkey and he is concerned for them — he said his father at one point was jailed for a week — but he downplayed the situation otherwise.“I was like, that’s it, only four years? All the trash I’ve been talking?” Kanter said. “I promise you guys, it doesn’t really bother me even bother me a little bit, because my thing is just going out there and playing basketball.”ADVERTISEMENT 8th Top Leaders Forum assessed the progress of public-private efforts in building climate and disaster resilient communities Brace for potentially devastating typhoon approaching PH – NDRRMC Kanter said he wasn’t concerned and continued his criticisms of Erdogan, saying, “That dude is a maniac.”“That stuff really don’t bother me because I’m used to it,” Kanter said after the Knicks practiced Wednesday (Thursday Manila time) in New York.FEATURED STORIESSPORTSWATCH: Drones light up sky in final leg of SEA Games torch runSPORTSSEA Games: Philippines picks up 1st win in men’s water poloSPORTSMalditas save PH from shutout“I think it’s just nothing to me, man. I’m in America. I’m good and my focus right now is just going out there, playing basketball, have fun with my teammates and just winning and just thinking about playoffs.”Kanter cannot return to Turkey because his passport has been canceled. He would be tried in absentia. Asian shares slide on weak Japan data; US markets closed Kammuri turning to super typhoon less likely but possible — Pagasacenter_img BI on alert for illegally deployed OFWs to Iraq MOST READ View comments Don’t miss out on the latest news and information. Read Next AFP FILE PHOTOANKARA, Turkey — Turkey’s state-run news agency says prosecutors are seeking more than four years in prison for NBA player Enes Kanter on charges of insulting President Recep Tayyip Erdogan.Anadolu Agency says an indictment prepared by the Istanbul chief prosecutor’s office accuses the New York Knicks player of insulting the president in a series of tweets he posted in May and June 2016.ADVERTISEMENT LATEST STORIES Cayetano: 4 social media groups behind SEA Games ‘sabotage’last_img read more

Thank You To Touch Football Volunteers

first_imgNVW is the largest celebration of volunteers and volunteerism in Australia, and provides an opportunity to highlight the role of volunteers in our communities and to say thank you to the more than six million Australians who volunteer across the country. The 2012 National Volunteer Week runs from Monday, 14 May to Sunday, 20 May 2012 and the theme for this year is ‘Volunteers – Every One Counts.’Touch Football has volunteers at many levels of the sport, from affiliate administrators through to referees, coaches, selectors and panel/executive members and the sport wouldn’t be as successful as it is without the help of these valued volunteers. TFA Chief Executive Officer, Colm Maguire, has praised the efforts of the volunteers involved in the sport of Touch Football, saying that their hard work is greatly appreciated. “Volunteers are a valuable and integral part of any sporting association and on behalf of Touch Football Australia I thank each and every one for their contribution,” Maguire said. Touch Football Australia would like to thank all of its volunteers for their contribution to our sport.last_img read more

10 months agoWolves defender Ryan Bennett agrees new deal

first_imgTagsTransfersAbout the authorPaul VegasShare the loveHave your say Wolves defender Ryan Bennett agrees new dealby Paul Vegas10 months agoSend to a friendShare the loveWolves defender Ryan Bennett has agreed terms over a new two-and-a-half year deal at Molineux.The centre-back had 18 months left on his old deal but will commit his future on improved terms until 2021, says the Daily Star.He has impressed in Wolves’ return to the Premier League with the club sitting 10th ahead of Saturday’s visit of Bournemouth.Bennett joined on a free transfer from Norwich in 2017 and helped Nuno Espirito Santo’s side win the Championship last season.He has made 49 appearances for Wolves, scoring once, and has played in 15 of the club’s 16 top flight matches this term. last_img

Nor Lines RollsRoyce Ink PowerbytheHour Service Deal

first_imgzoom Norwegian shipping company Nor Lines and UK-based engineering company Rolls-Royce have signed a “Power-by-the-Hour” service agreement for Nor Lines’ two LNG-powered vessels, Kvitbjørn and Kvitnos.The new service offering harnesses the power of Big Data to monitor, plan and perform maintenance and repairs on all the equipment installed on the cargo vessels, Rolls-Royce said.As disclosed, Power-by-the-Hour is a new service from Rolls-Royce Marine and the agreement with Nor Lines is the first of its kind. Under the agreement, Nor Lines will be handing responsibility for service planning and performance back to the equipment’s supplier, Rolls-Royce.With Nor Lines paying a fixed charge per hour of operation, per ship, Rolls-Royce will monitor the equipment aboard each vessel from on shore through the use of onboard sensors. The engineering company will be able to connect to the ship and carry out service activities remotely or, if necessary, send out a service engineer to do the job.The agreement also covers planned maintenance, while day-to-day maintenance aboard ships will be carried out by the shipping company itself.“The service contract insures us against downtime due to equipment failure. At the same time, it ensures that the Rolls-Royce equipment we have on board functions as optimally as possible,” Sigvald Breivik, Nor Lines’ CEO, explained.Nor Lines has also ordered Rolls-Royce’s Energy Management System, which logs energy consumption and emission levels. The data then can be used to make the correct operational decisions for the ships.“Both the Power-by-the-Hour and Energy Management systems have been developed because we now have the capacity to digitally monitor onboard systems from on shore. Our ability to record and analyse huge volumes of data means we can offer ships better and more comprehensive service agreements than we could just a few years ago,” Knut Hovland, Rolls-Royce, Director Customer and Services, commented.Nor Lines took delivery of MS Kvitbjørn from the Tsuji shipyard in China in 2015. It was the first of two vessels ordered by the shipping line and was the first Norwegian gas-powered coastal cargo vessel. The Kvitbjørn’s sister ship, MS Kvitnos, was delivered later the same year.Now, the vessels sail back and forth between ports in central Europe and along the Norwegian coast up to Hammerfest.last_img read more

Silicon Valleys Jumio launches AI lab in Montreal to hone ID verification

first_imgMONTREAL – Jumio has opened an artificial intelligence lab in Montreal, adding to the city’s ranks of machine-learning firms.The Silicon Valley company says it plans to work on fraud detection and data extraction as part of a push toward refined identity verification.Jumio says the satellite lab, which numbers seven employees after quietly opening last month, will have 30 engineers and specialists by the end of next year. The lab expands on work underway at the company’s Vienna-based AI hub.Over the past year, Ottawa and Quebec have pledged more than $300 million toward AI development in Montreal, while tech giants Google and Microsoft Corp. have invested in machine learning research.Startups in the city are exploiting AI to build technology applicable to everything from tumour detection to navigating the immigration process.In 2016, Jumio filed for bankruptcy protection for its U.S. business following government investigations into financial irregularities, but raised US$15 million in funding a few months later.last_img read more

Toronto stock market starts November by posting third day of positive growth

first_imgTORONTO – Canada’s main stock index started November by notching a third straight day of positive growth led by higher metals and materials.Despite the bounce back from a very weak October, it may be premature to celebrate just yet, says Kash Pashootan, CEO and chief investment officer at First Avenue Investment Counsel Inc.“We’re not getting overly enthused or turning positive just yet because we feel that it’s still too early to say we have turned the corner,” Pashootan said in an interview.Being late in the bull run, he said it’s difficult to see how equities will generate even high single-digit increases amid volatility.Some of the tech and industrials names that led the correction have regained some footing over the past three days amid strong third-quarter corporate results that helped to inject positive sentiment.But Pashootan said some big companies that have yet to report could be a determining factor if the bounce back will stick — chief among them is Apple Inc.“We’re going to need the world’s largest company to have solid numbers reported, or otherwise you could see a quick reversal of this three-day optimism that’s come back,” he said.The company reported fiscal fourth-quarter earnings of US$14.13 billion after markets closed. The net income of $2.91 per share surpassed Wall Street expectations of $2.79 per share. But its holiday outlook suggested weaker demand for expensive new iPhones.The S&P/TSX composite index closed up 122.87 points to 15,150.15. Metals, materials and gold rose by at least 3.7 per cent, while utilities, financials, utilities and consumer staples led on the downside.It’s been a good week for the Toronto Exchange.“You’re seeing this tug of war continue between the market trying to decide if overall it’s feeling optimistic because of Q3 earnings or it’s still trying to finish the cleansing process of the correction that started a couple of weeks back,” Pashootan said.In New York, the Dow Jones industrial average gained 264.98 points to 25,380.74. The S&P 500 index was up 28.63 points to 2,740.37, while the Nasdaq composite was up 128.16 points at 7,434.02.The Canadian dollar traded at an average of 76.41 cents US compared with an average of 76.09 cents US on Wednesday.The December crude contract was down $1.62 to US$63.69 per barrel and the December natural gas contract was down 2.4 cents at US$3.24 per mmBTU.Crude is down about five per cent for the week but more decreases are likely, noted Pashootan.“Investors should be watching in the coming months because the real reasons why the commodity price rose in the first place not being supply and demand, but more so supply disruptions.”The December gold contract was up US$23.60 at US$1,238.60 an ounce and the December copper contract was up 6.25 cents at US$2.72 a pound.last_img read more

Hydro One Q3 profit drops to 194 million from last years strong

first_imgTORONTO ONTARIO, – Hydro One Ltd. is reporting that its net profit decreased by 11.4 per cent in the third quarter to $194 million.The parent company of Ontario’s largest electricity transmission and distribution utility says it earned 32 cents per diluted share for the period ended Sept. 30, compared with $219 million or 37 cents per share a year earlier.The prior year’s profits were boosted by regulatory catch-up revenues and a lower effective tax rate.Excluding one-time items, adjusted profits slipped 4.2 per cent to $227 million or 38 cents per share, from $237 million or 40 cents per share in the prior year.Revenues were $1.61 billion, up 3.1 per cent from $1.52 billion, reflecting higher consumption from favourable weather.Hydro One was expected to earn 35 cents per share in adjusted profits on $1.61 billion in revenues, according to analysts polled by Thomson Reuters Eikon.Companies in this story: (TSX:H)last_img read more

Environment Canada issues winter storm warning for Fort Nelson

first_imgThe band of snow is expected to shift to the southwest towards Sikanni Chief tonight, where 10 to 15 cm is forecast.Rapidly accumulating snow could make travel difficult over some locations.Drivers are being reminded to prepare for quickly changing and deteriorating travel conditions.For up-to-date road conditions, you can visit FORT NELSON, B.C. – Environment Canada has issued a winter storm warning for Fort Nelson.According to Environment Canada, Hazardous winter conditions are expected.Snow at times mixed with freezing rain will continue this afternoon through tonight before easing Thursday morning. Approximately 10 cm of snow has already fallen this morning around Fort Nelson with a further 5 cm this afternoon.last_img

Summer care tips to beat this heat

first_imgAs Summers are here, so are many problems related to skin. Experts list down a few tips for you to fight this season gracefully:Get rid of uneven patches: For the lips which are extremely vulnerable to have unbalance tone and texture, mix 1 spoon of lemon juice some raw honey apply this paste on your lips and rub it for like 3-4 minutes. Thereafter, wipe it off. After this process apply some balm or home based oil for nourishment. you can replace honey with brown sugar. Also Read – An income drop can harm brainHydrate your body and hair: When the Summers strikes, keep your body hydrated by drinking lots of plain water and coconut water. Coconut is good for skin and hair also. For your hair, mix a fine paste of one banana, 2-3 spoon of coconut oil and 1/3 cup of plain curd. Apply this paste on your hair from roots to your hair length, massage your hair for about 5 minutes. Keep this mask for 50-60 mintues for better result and rinse your hair with mild shampoo. Also Read – Shallu Jindal honoured with Mahatma AwardKeep your face acne free and smooth: Summers are the season of oliy skin, and it is the main cause of acne on our face. Take orange peel powder, Aloe Vera gel and rose water mix these three ingredient and apply it on your face for glowing and acne free skin. Control oil on skin: Be it Summers or chilly winters, never leave your skin non-moisturised. Otherwise, the skin will produce more oil on your face. Use clay based mask as they absorb the excess oil for better result use this mask for 2-3 times in a week. Night Cream: Night care is the most important step for a good skin. Add few drops of tea tree essential oil to your aloe vera gel and use it as a night cream and deep moisturise your skin throughout the night. (Inputs shared by Arpita Das, Skin Care expert).last_img read more