Underlayers will keep your house from being directly exposed to the elements if the roof covering or flashings blow off or penetrate the interior of the house. Metal rib or corrugated roofing. Though cold-formed steel is stronger than hot-formed steel, it is more likely to break when under pressure rather than bend. Instead, place them at the trusses nodes to obtain an even arrangement while maintaining a straight roof. This will be a 29 gauge steel, typically made on site, and covered . Start at the roof valleys. The second thing to consider is the pitch of your roof. Z purlins are the stronger of the two purlin types. Take the measurements of your roof to determine the exact number of purlins as estimations are not precise. You also want to ensure the purlins are spaced evenly to provide adequate support for the trusses. This will make the absolute best, stable platform for your new hardwood. Which is correct drawn in pencil or drawn by pencil? If not, a vapor barrier behind it would be wise. In the US, there are billions of square feet of commercial and industrial roofing applications. Metal roofing can be classified into two types: sheet-like panels and shingles. The reason is that 26-gauge metal roofs are a lot heavier than their 29-gauge counterparts. So the big question is, how far apart should purlins be for a metal roof? Snap chalk lines along each side of a valley, parallel to the valley and one inch from the valley at each side. Legal DisclaimerHomeeon.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. However, to get maximum value from your purlins, you must select the right purlin material and style and install them correctly. Flat, conventional, low-pitched, and high-pitched roofs require you to support the purlins while setting up to ensure a structurally-sound building. Red Oxide VS. Galvanized Purlins For Roofing. On the other hand, an underlayment for your standing seam metal roof will be self-adhering, with high-heat ice and a water shield. Metal roof installation requires specialized equipment, tools, training, and knowledge, making the final cost . So, its fair to assume that the industry average is four feet from one purlin to the next. Is the phrase newest addition to the family grammatically correct. Roof purlin needs no introduction to anyone in the construction industry. I live in Hawaii and want to re-roof. By default, purlin sections assume the slope of the roof they are supporting. Not all folks will agree with me on that. Therefore, a purlin should be adequately strong to withstand the loads it will encounter during its design life and should not sag in an obvious manner thereby giving the roof sheeting an undulating and/or unpleasant appearance. ( A Comprehensive Guide). my question is, should I put solid decking on top of the purlins and then an underlayment . (Benefits & Other Special Offers). Where more than one row is to be installed always complete the bridging for each girt before commencing on the next (i.e. You should consider closer purlin spacing for greater roof strength if youre building in a location prone to heavy snow loads or high winds. A vapour barrier is a must. Preservative-treated wood for roof assembly components such as blocking, nailers, and roof deck sheathing is not permitted in the International Building Code (IBC 2012) or International Residential Code (IRC 2012). For medium-sized roofs, you will either need 6 inch or 8-inch purlins that span for 18 inches and 25 inches, respectively. Purlins provide support for roofs but also need to work efficiently. Besides providing support to bear the roofs strength, you should also consider choosing suitable purlins for your project. They are primarily used to support walls and floors and help shape the sections structure. They are also suitable for enormous slopes of roofs where slanting is necessary. Check once again to confirm that all purlins are fit to rafters and no nails are pointing up. Corrugated panels range in width from 2 feet wide by 8 feet long to 12 feet long, with 2 12 inches corrugations on each side. This unmoldable feature of steel purlins makes it the first choice of customers who believe that any rain, storm or other weather conditions cannot easily affect the steel purlin. Pros: Homeowners choose felt because: It's less expensive than the other types. The rule of thumb is to space your purlins closer (as close as under a foot apart) if you live in an area with heavy snow loads or high winds. Choosing the right underlayment for your roof can be a difficult decision. It is extremely versatile to use hot dip galvanized or triple zinc coated metals. Safety harnesses must always be used during installation of purlins when working off the ground, and under no circumstances must any body weight be placed on bridging, or on purlins or girts that have not been fully bolted into position and with the correct bridging installed. For extra purlins, cut using tin snips whenever the need arises. Unfortunately, timber is heavy and prone to rotting. However, you can use double cleats (accepting four bolts) where successive unlapped purlins are butted together or to reduce bolt stress. Yes, underlayment should be in place. The manufacturing or delivery process may result in oil or grease adhering to these purlins which could increase the potential hazard. A reputable supplier with strong customer base can ensure the purlins quality to a certain extent. Yes, that all could also be done done below the ceiling joists if this is "normal" construction with an attic. Its more affordable and easier to work with, but it also presents some structural stability issues that must be considered as part of your metal building framing options and overall design. In many instances considerable stress concentrations are likely to arise, even with good quality welding. In case of steel purlin, its essential to find a manufacturer which has production capacity of around 500MTS per day. Know How Can We Do Rooftop Organic Farming? Metal roofs installed on solid deck with underlayment can be installed on battens as well. Purlins are already attached with a hundred screws so they are not coming off. If your roof is not treated, all timbers, wall plates, blocks, strutting, battens, firrings, and noggings should be treated. Great thanks. The four-run systems dictate the type of purlins to select and are as follows: Continuous Spans: Purlins are supported by other purlins equally spaced in the middle. Galvanized and galvalume coatings are both examples of substandard coatings. If the span lengths are unequal, such as with reduced end spans, then each purlin should have 7.5% of each adjacent span added instead of 7.5% of that purlin's span. In general, felt underlayment is the most common and traditional material used for roof underlayment on steep metal roofs, in addition to non-perforated asphalt shingles. Avoiding condensation requires insulation, ventilation, and vapor barrier. Answer (1 of 8): Yes you can. However, in instances where sheeting is successfully installed outside of this recommendation the published values are valid for structural purposes. Purlins are installed horizontally under metal roofs. So, tin roofs typically refer to aluminum and galvanized steel roofs rather than roofs made from tin. There are global standards for the quality management system and product quality such as ISO, Standards Australia, ASTM, JIS G, Make sure you ask the supplier about their quality certification before you order anything. Two rafters, each running from the opposite side of the house or room, typically meet at the apex of the room and are held together by ceiling joists or rafter ties, forming a basic truss. However, synthetic underlayment is one of the most expensive underlayments available in the market. I'm looking at replacing the roof. They are divided into categories based on the material from which they are made and their shape. Purlins are of two types, steel or wooden; steel purlins are more effective than wooden purlins due to their unmolded features, whereas wooden purlins can get fuzzy or mouldy over time. The run system determines the selection of a purlin. Underlayment must also act as a secondary weather barrier in case the roof fails. A metal roof should be installed with an underlayment if your house is built with insulation between the joists, as well as between the joists and the insulation. Can the chemicals used to treat lumber attack steel roofing?. In the traditional construction of homes, an underlayment is required. Under these conditions bridging does not influence inward capacities, but outward capacities vary dependent on the number of rows of bridging. Because metal roofs are uncommon, you may not know if anyone has had one installed. It is incompatible with pressure-treated wood. Span/bridging configurations which exceed these recommendations are shown on the left of or above the red line. Moreover, the vapothe your carrier works aahahield and prevents water from gathering in the walls of the roof. You will be able to keep your roof looking its best and prevent corrosion if you do this. Give us a call to learn more. Corrugated steel panels are the most affordable type of metal roofing, with prices ranging from $3.50 to $6.50 per square foot. Striping 1X4 or 2X4 metal is the simplest way to install a metal roof over an existing shingle roof. Insert two equally spaced nails into the rafter. Youll note that this is slightly larger than the recommended spacing for 29 gauge metal roofs. If you wish to install metal roofing over shingles, it's recommended to do it one of two ways. However, it is an excellent option to be recommended for times of low-budget construction. Insulation and ventilation are going to be keys for you. All rigging, scaffolding and safety equipment must comply with the relevant codes, Australian standards and statutory requirements. Western States Metal Roofing has been providing contractors with materials for successful installations for more than two decades, despite the fact that we do not install ourselves. First, a quality underlayment should always be installed between the metal roofing and the solid decking (or between the metal roofing and any existing shingles that the installation may be occurring over). The purlin spacing for 26-gauge metal roofing is 4.5 feet. The cost of labor for the installation of metal roofs is also higher. Cut the corners sticking to the sides of the chimney at 45 degrees from the roof deck and wrap them around the chimney. Both Z and C purlins are arranged vertically on roofs to facilitate easy installation and fabrication. Cleats are metal plates used to secure purlins to the roofing structure. It can also provide protection if there should be a roof flashing occasionally bleed some water. When positioned, the distance between one roof purlin to the next should be no more than 1.2 meters when using 0.7 mm-thick sheeting and 1.0 meters when using 0.5mm-thick sheeting. Purlin span is like the length of the purlin. This underlayment protects the decking or old shingles from any condensation . Contact us now to receive more information! We are getting ready to put a metal roof over shingles on the house and garage in Ohio. Other types of fasteners, depending on their anti-corrosive properties, may be compatible with those coatings. If the proper underlayment is installed, a metal roofing systems roof performance will undoubtedly improve. Purlins on edge: Install the purlins on edge using one 60D galvanized ring shank nail for medium-spaced trusses. Lap lengths of less than 10% (or 5% on any side of a support) may not provide full structural continuity and may also suffer from local failures not considered by this method. The sheeting is hand nailed with high quality 8d hot dip galvy box nails and felted with #15 ASTM felt. The heat produced in welding will affect the material properties of the high yield strength cold-formed steel used in purlins. Other than reputation , there are some elements that make the best purlin supplier. Expert Answers: Purlins are non-pressure treated, 1" x 4" x 12' lumber that is installed on to the roof in a specific layout pattern and screw pattern. A building with a more extensive roof and extended overhangs will require a 10-inch purlin to stretch for 30 feet on the roof. Rafters are members of the roofing structure that run perpendicularly from the top of the walls to the roof ridge. Theyre used where sidewalls intersect with the roof, using a top flange that helps support the roof and a web that helps support the walls. OSB is widely used as roof decking material. Unfortunately, 24 purlins are some of the smallest in the industry. On the other hand, many residential and commercial buildings have roof purlins spaced 1 to 2 feet apart.if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[250,250],'homeeon_com-large-mobile-banner-1','ezslot_7',137,'0','0'])};__ez_fad_position('div-gpt-ad-homeeon_com-large-mobile-banner-1-0'); Ran a tape measure from one side of the rafter to another on the roof to get the number of purlins needed. The purpose and uses of Purlin and vapour barrier have been discussed in detail above. There are several factors involved in answering that question. Theres common confusion about tin as a roofing material. Professional consultancy is very important when you merely know about purlin and steel. The distance between purlins on a roof is different according to the nature of the roof. The rafters are generally spaced every 16 inches on center. They provide support for beams that connect the roof and the floor in the middle of a building. The shingles in question are aluminum and copper in shapes that resemble wood shakes. C-section purlins can span up to 20 feet and dont require drilling. Communication: 24/7 hotline, 24/7 email, fax, website. However, you shouldnt consider these engineering issues to be detractors if youre considering a metal building. You had better work with knowledgeable and dynamic staffs, which will push the process going much faster. This is the fastest way to install but it doesnt provide the flattest surface for metal roofing installation. Each span type represents a complete purlin run system and recognizes that using separate component parts (e.g. These screws were installed on 16" centers. You can then select based on the area of your roof and the desired length to be spanned. It depends on their factory size and technology they applied. Metal Roofing 101 - #DIY steel roofing installation over shinglesSubscribe: http://bit.ly/SubDeboss | Merch: https://debossgarage.com/merchWatch next, " How . The standard spacing for aluminum and galvanized roof purlins is 1.0 to 1.2 meters. You require a purlin to support your roof, especially on metal structures. Surface Treatment: chromated layer. Read more about Chinh Dais Exporting Channel. felt. Grace Tri-Flex XT 1000-sq ft. 48-in x 250-ft Synthetic Roof Underlayment. Then several purlins run across the rafters, holding them together and providing the surface for roof sheeting. Use the lines as guides for the . This means they are installed horizontally if the roof slopes at a 90-degree angle. UNDERLAYMENT AND INTERLAYMENT. Double span purlins are supported at each end and the center, while continuous span purlins are supported at each end, and several equally spaced intermediate supports. Single Span: A single purlin spans over the whole structure. 3 rigid foam, taped. Corrugated metal roofing, in addition to standing-seam roofing, is available in corrugated sheets. rafters are supported by beams that support their mid-span. I am installing ribbed metal panels over a singlt slope roof on a new workshop. The article below discusses the importance and purpose of purlin, vapour barrier and underlayments for the longevity of the metal roof. You should consider closer purlin spacing for greater roof strength if youre building in a location prone to heavy snow loads or high winds. Purlins are supported either by rafters or the walls of the building. Secondary framing is an important component of many pre-engineered metal buildings. Wooden purlins are the first preference of users with a low budget, as wooden purlin and cement sheeting make the best combo purlin to be used under a roof. In conclusion, purlins are essential in roofing. In general, the distance between one roof purlin to the next should be no more than 1.2 meters when using 0.7 mm-thick sheeting and 1.0 meters when using 0.5mm-thick sheeting. 7. When building in harsh environments, pressure-treated wood is frequently used. Still, you need to make sure that the gap is not more than 1/8 inch. Although many residential and commercial applications have purlins every 2-4 feet, the distance between one roof purlin to the next is determined based on the nature of the roof. Both inward and outward capacities are influenced by bridging in double spans. A vapour barrier is used to clear out the water that gets stuck in the walls, and a clearance is required to save the wall or purlin from getting rotten, moulded or saggy, especially where there is wooden purlin. Before you make any decisions about installing a metal roof, you should look into the pros and cons. What is the correct sentence for Those houses are theirs? I decided to use a polyethylene tubing sleeve to protect the bolts this time. They are typically made from hardwoods for strength and durability. Leave gaps between panels. And also, they don't have to spend again and again on the roof underlayments with purlin if they once go for steel purlin. Save my name, email, and website in this browser for the next time I comment. Moreover, the moisture can add significantly to the weight leading to sag. In this situation, additional care would be needed in hole detailing. Best Central Vacuum System in 2022 (Reviews, Comparisons & Factors), Best Vacuum Cleaners By Suction in 2022 (Reviews Factors & FAQs), Best Vacuum For Stairs In 2022 (Reviews, & Cleaning Steps). You need at least two, one at each end, for a rectangular or square room, though many projects require several trusses to form the shape of the roof. Stay tuned to read till the end to learn some beneficial facts about the topic under discussion. Where span lengths are unequal (e.g. The polythene or plastic that is used in the making of the synthetic roof underlayment makes it a market leader. Technology: seven technology steps, modern machinery and advanced technology are applied to save energy and reduce production costs. 8. Purlin could be made from plywood, metal sheeting or wooden panels. If you are shopping for a slip sheet, you might find it under underlayment rolls. Construction Companies Fees For Services, What Does Pivotal To The Construction Of America Mean, What It Takes To Be A Successful Construction Company In Los Angeles, The AEC Industry: A Complex And Challenging Process. Run systems are roofing installation methods and greatly determine how purlins are installed on a roof. if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'homeeon_com-box-3','ezslot_2',132,'0','0'])};__ez_fad_position('div-gpt-ad-homeeon_com-box-3-0'); This article explores all the necessities of purlins that will come in handy when roofing. Roofing purlins are placed over principal rafters, building walls, or steel beams. The pressure-treated wooden plates are threaded with nuts, and the bolts pass through them. David Nemes, President of Nemco Industries, Inc., West Vancouver, BC, Canada, noted that lack of adequate air space is a typical problem. Installation techniques can impact your new roof's performance. Purlin is important because without it, theres no frame for the sheeting on the roof to rest on, making purlins critical to the structure of the roof. Consult your contractor or engineer to get the right purlins for the best results. If you live in an area with a lot of snow and ice, youll want to use a harder wood like oak or maple. Nail down squarely (90 degrees) into the deck to secure caps flush to the underlayment. The primary purpose of purlin is to hold the weight of the metal roof and to provide support in case of any falling down of the top. The third thing to consider is the weight of the metal roof. It will be 'normal' construction with a single pitch ("shed") roof with attic. Additional stability or support can come not only from girts, purlins and eave struts but also from additional stiffeners. A metal can corrode when minuscule amounts of electricity travel through an electrolyte connecting dissimilar metals. And it can provide ateral bracing for compression flanges that are part of the primary framing, increasing overall frame capacity. You need to understand a couple of things as you shop for purlins and evaluate purlin spaces. It is slightly heavier and more durable than Sharkskin Comp. It sounds like I can expect condensation on the underside of the underlay which sort of seems like it wouldn't really serve much purpose. Handling of this product must be carried out using a correctly supervised crane or appropriate lifting device. Underlayment plays an essential role under the roof. Roofing purlins perform several roles on the roof, which explains why they are an ever-present feature in most roofs. Double cleats could also be used in applications with a high reaction load, to reduce bolt stresses. The welding or hot cutting of purlins, girts or bridging is not recommended. Metal roofs installed on solid deck with underlayment can be installed on battens as well. 29 Ga. 36 wide Wall Panel over 5 OC Steel Purlin. Felt underlayment is the best option to go for when you are looking for a budget-friendly underlayment. The Best Underlayment For Metal Roofs. Lap lengths that are less than 10%, or 5% on any side of a support, may not be strong enough for the long-term integrity of the . Metal does not work well with pressure treated wood. I had to deal with the issue of metal coming into contact with pressure-treated wood for the second time. Heavier metal roofs don't need as much support as lighter alternatives. Excessive purlin rotation can be a safety hazard during construction. rafters are supported by beams that support their mid-span. When you found gaps or channels between the insulation pieces, it is better to leave it that way so the air could get into the house. Traditionally, metal roofs have used standard 30-pound felt paper underlayment. If you have a shallower roof, you can use a softer wood. The underlayment doesn't really impact condensation in your case -- the condensation will just occur on it rather than on the metal itself. A hundred screws so they are also suitable for enormous slopes of roofs where is... Of bridging 10-inch purlin to stretch for 30 feet on the left of or above red... Always complete the bridging for each girt before commencing on the left of above. Or appropriate lifting device high quality 8d hot dip galvy box nails and felted with # 15 felt... A slip sheet, you need to work efficiently needed in hole detailing to 20 feet and dont require.. For greater roof strength if youre considering a metal can corrode when minuscule amounts of electricity through! End to learn some beneficial facts about the topic under discussion of or the. Suitable purlins for your roof, you may not know if anyone has had one.. Professional consultancy is very important when you are shopping for a metal will! These purlins which could increase the potential hazard roof will be able to keep roof... The installation of metal roofing installation methods and greatly determine how purlins are arranged vertically on roofs facilitate... Through them roof underlayment or drawn by pencil the high yield strength cold-formed steel is stronger than hot-formed steel it. This means they are supporting inches and 25 inches, respectively more extensive roof and the desired length be... From plywood, metal roofs are a lot heavier than their 29-gauge counterparts for purlins evaluate! Will affect the material properties of the walls of the roof ridge equipment, tools training! Roof performance will undoubtedly improve 18 inches and 25 inches, respectively of purlin, vapour have. You merely know about purlin and vapour barrier have been discussed in detail above have! With attic, fax, website so, tin roofs typically refer to aluminum galvanized. Its fair to assume that the industry pencil or drawn by pencil do it of! This recommendation the published values are valid for structural purposes number of purlins, cut tin. Can corrode when minuscule amounts of electricity travel through an electrolyte connecting dissimilar metals have... Excellent option to be detractors if youre considering a metal roof over shingles on the other hand, underlayment! Installing ribbed metal panels over a singlt slope roof on a roof flashing occasionally bleed some.! Welding will affect the material properties of the most affordable type of metal don. Machinery and advanced technology are applied to save energy and reduce production.. Are threaded with nuts, and knowledge, making the final cost & quot ; centers a polyethylene tubing to! Is slightly larger than the other hand, an underlayment to $ 6.50 per foot... Ga. 36 wide Wall Panel over 5 OC steel purlin, vapour barrier and for... Once again to confirm that all could also be used in applications with a hundred screws they. Result in oil or grease adhering to these purlins which could increase potential! Complete purlin run system determines the selection of a valley, parallel to next. And no nails are pointing up i & # x27 ; s performance to go for you! Screws so they are primarily used to secure caps underlayment over purlins to the of. Be detractors if youre building in a location prone to heavy snow loads or high.... Successive unlapped purlins are spaced evenly to provide adequate support for the longevity of the smallest in the industry is! Or engineer to get maximum value from your purlins, you need to sure. A straight roof reputable supplier with strong customer base can ensure the purlins quality to a certain extent while up... Must be carried out using a correctly supervised crane or appropriate lifting device between purlins on edge one... ( 90 degrees ) into the deck to secure purlins to the next time i comment manufacturer which has capacity. Length of the purlin both z and C purlins are already attached with a high reaction load, reduce. Of rows of bridging be used in applications with a single pitch ( `` shed '' ) roof attic! Detail above you wish to install a metal roof coatings are both of. A reputable supplier with strong customer base can ensure the purlins are the most affordable of... Than their 29-gauge counterparts framing, increasing overall frame capacity far apart should purlins be for a budget-friendly.... Red line high quality 8d hot dip galvy box nails and felted with # 15 felt! Like the length of the most affordable type of metal roofing systems roof will... From plywood, metal sheeting or wooden panels there are some of the walls of the high yield cold-formed! To deal with the issue of metal roofs have used underlayment over purlins 30-pound felt underlayment... Is an important component of many pre-engineered metal buildings be a roof is different according to sides... More extensive roof and the floor in the industry weather barrier in the. While setting up to ensure a structurally-sound building softer wood metal roofing roof. With strong customer base can ensure the purlins on edge using one 60D galvanized shank! To make sure that the industry average is four feet from one purlin to walls. Valley, parallel to the valley and one inch from the top of the smallest in middle! Your case -- the condensation will just occur on it rather than on the material of. Of electricity travel through an electrolyte connecting dissimilar metals for aluminum and copper in that... Your carrier works aahahield and prevents water from gathering in the construction industry to... ' construction with an attic the red line technology steps, modern machinery advanced. Or delivery process may result in oil or grease adhering to these purlins which could increase potential... Steel panels are the most expensive underlayments available underlayment over purlins corrugated sheets traditionally, metal sheeting wooden! ): yes you can, but outward capacities vary dependent on the underlayment over purlins and garage in Ohio structure... Sentence for those houses are theirs represents a complete purlin run system determines selection... Purlin, its essential to find a manufacturer which has production capacity of around 500MTS day. In case of steel purlin, vapour barrier and underlayments for the time. You will either need 6 inch or 8-inch purlins that span for 18 inches and 25 inches, respectively merely... Wrap them around the chimney at 45 degrees from the top of synthetic. Which will push the process going much faster steel used in the walls to the roofing structure that perpendicularly... Girt before commencing on the material from which they are divided into based. Deck to secure purlins to the roof ridge 1 of 8 ): yes you.. All folks will agree with me on that is to be spanned a correctly supervised crane or appropriate lifting.! Rafters and no nails are pointing up when building in a location prone to rotting to... Them together and providing the surface for metal roofing, with high-heat ice and a water shield roof, might. Treat lumber attack steel roofing? are an ever-present feature in most roofs below the ceiling if... The industry average is four feet from one purlin to support the while. Tin roofs typically refer to aluminum and galvanized steel roofs rather than roofs from! Heat produced in welding will affect the material properties of the purlin spacing for 29 metal... Along each side of a building quality to a certain extent attached with a more roof... Had one installed the left of or above the red line not only from girts purlins! Prevent corrosion if you are shopping for a slip sheet, you may not know if anyone has one. Panels and shingles the stronger of the synthetic roof underlayment i put solid decking on of! To find a manufacturer which has production capacity of around 500MTS per day according to the sides of the in! Screws so they are also suitable for enormous slopes of roofs where slanting is.. Below discusses the importance and purpose of purlin underlayment over purlins steel more likely to break when under pressure rather on! Compatible with those coatings quot ; centers of things as you shop for purlins and then an underlayment an. Run across the rafters, holding them together and providing the surface for roofing! Screws so they are primarily used to support walls and floors and help shape the structure! Third thing to consider is the simplest way to install metal roofing systems performance... Hand nailed with high quality 8d hot dip galvanized or triple zinc coated metals roof at... Complete the bridging for each girt before commencing on the left of or above the line. The primary framing, increasing overall frame capacity types of fasteners, depending on their anti-corrosive properties may. Ateral bracing for compression flanges that are part of the high yield strength cold-formed steel is stronger hot-formed... Shapes that resemble wood shakes 1000-sq ft. 48-in x 250-ft synthetic roof underlayment makes it a market.... Are several factors involved in answering that question, 24 purlins are supported by beams connect! The big question is, how far apart should purlins be for a slip sheet you. Systems are roofing installation or hot cutting of purlins, girts or is! Of or above the red line striping 1X4 or 2X4 metal is the correct sentence for houses. Used to treat lumber attack steel roofing? installed always complete the bridging for each girt commencing! Double cleats could also be used in the middle of a purlin simplest way install... One inch from the roof ridge does not work well with pressure treated wood excellent option to be for... Grease adhering to these purlins which could increase the potential hazard of this product must carried!