Tag Archives: standing seam

Clip-Lock Standing Seam, Adding a Ceiling, and Knee Brace Issues

This week Mike the Pole Barn Guru answers reader questions about replacing roofing with clip-lock standing seam and what the PBG recommends in the scenario, creating a wood shop in an existing structure and wondering if ceiling weight can be held, the possibility of removing knee braces in order to install a ceiling.

DEAR POLE BARN GURU: I am leaning toward replacing with clip lock standing seam on 2×4 purlins every foot on center. My installer wants to do away with the vapor barrier and stretch synthetic underlayment over the purlins. What do you recommend in this scenario? JAVO in PRINCE FREDERICK

DEAR JAVO: Clip lock standing seam panels have no ability to transfer wind shear loads and should only be installed over 5/8″ CDX plywood sheathing. If not, your building is likely to rack (or even fail) due to wind loads. There are other reasons to use sheathing: https://www.hansenpolebuildings.com/2015/08/standing-seam-steel/ In summary remove vapor barrier, install plywood with synthetic underlayment between plywood and standing seam steel.

 

DEAR POLE BARN GURU: Hello, I have an existing pole barn/garage but I have very little information about it. I would like to create an interior room for a woodshop but I don’t know if my trusses would support a ceiling and the necessary insulation. Is this something you can help with? CHAD in GRASS LAKE

Installing a ceilingDEAR CHAD: Unlike all Hansen Pole Buildings with spans of 40 foot or less (where we have our interior double trusses always designed to be able to support at least a minimal ceiling load of five pounds per square foot), most pole barn trusses are not ordered or designed to support any sort of a ceiling. Many times trusses will have a stamp on them stating truss spacing and loads, if so, you want a Bottom Chord Dead Load of 5 psf or greater. If nothing else, truss manufacturer’s stamp will tell you who fabricated those trusses and you can reach out to them to verify adequacy. If they do not have records available, or are no longer in business, you should engage a Registered Professional Engineer to perform a field inspection to verify adequacy, or to provide an engineered repair.

 

DEAR POLE BARN GURU: I have a 30′ x 48′ x12′ pole barn that has Knee braces. I am wondering if I am able to remove the knee braces on this type of rafter to eliminate having to cut around each one as I am installing interior liner steel. The rafter top chord is 2×10, the bottom chord and webs are 2×6 and the rafters are adjoined to the poles appx 30′ below the bottom chord. The rafters have fink style webs. JOSH in CANBY

DEAR JOSH: In fairly recently built pole barns, I would have encouraged you to reach out to whomever originally engineered your building. Your building obviously has been around (somehow) for more than a few years. I say this “somehow” in all seriousness as your roof system does look questionable. It very well could be compromised by any changes – even weight of steel liner panels. Best bet is this – hire an engineer to do an actual physical examination of your building to determine if knee braces can be removed, any structural changes needed if they are to be removed, as well as adequacy to support any sort of ceiling. Think of this as an investment, rather than an expense, especially if it prevents a failure.

Weather Resistant Barriers, LVL Notches, and Design Ideas

This week the Pole Barn Guru answers reader questions about weather resistant barriers, a caution to not attempt to notch LVL rafters, and a recommended design solution for a new build.

DEAR POLE BARN GURU: We are in process of designing our barndominium with hoping to start building next spring. Do you have a recommendation as to what water resistant barrier (WRB) to use with closed cell spray foam? Planning on using a standing seam metal roof and wainscot siding at this time. I know that a reflective barrier is useless without an air gap behind it. Using spray foam prevents its use. I’ve researched several, like zip system, Tyvek, and others. Thanks for answering my question. GREG in CARROLL

DEAR GREG: In your climate zone I would typically not recommend using spray foam other than as two inch thickness applied directly to steel roofing and/or siding in order to control condensation. This does result in having to mechanically control humidity as your building will now “dry” to inside. As standing seam steel does not provide shear resistance, it must be installed over solid decking – and you can spray foam directly to this decking underside.

In any case, it is not recommended to use closed cell spray foam applied to any WRB. For extended reading: https://www.hansenpolebuildings.com/2020/04/spray-foam-insulation-3/

 

DEAR POLE BARN GURU: I got a pole barn I’m putting up. The purlins were designed to run over end rafter bit that makes eve low. Can a 1 ½” x3 ½”(2×4) notch for outrigger for eave support and run end rafter up like others in the center. Notch would be 1 ½” deep on an 11 ¾” lvl. One in center span and one at top of roof. This is on the shed roofs only. MIKE in RAVENSDALE

DEAR MIKE: Absolutely do not cut or notch into your end rafter. You need to lower end rafters to allow purlins to go over top of end rafters without any notching.

While you are at it – have your building’s engineer recheck those shed rafters and purlins closest to main endwall to confirm they are adequate for snow drift loads. Usually purlins closest to endwalls have to be much closer together to adequately support those loads.

 

DEAR POLE BARN GURU: I want to space my poles 8′ apart and use to 2×12, one inside and one outside at the top to place standard trusses on the top so i can add an insulated ceiling in it. Any comments on this, and how deep do my posts have to go into the ground? LARREN in DAVIS CREEK

DEAR LARREN: Personally, I would throw away your proposed design solution.

In most instances, you are better served with sidewall columns spaced every 12 feet. Use a true two-ply truss, aligned with every sidewall column (https://www.hansenpolebuildings.com/2018/09/true-double-trusses/) and notched in. Trusses should be engineered to carry a ceiling (bottom chord dead load – BCDL). Use five (5) psf (pounds per square foot) for a steel ceiling and 10 psf if sheetrocked. Between bottom chords of pairs of trusses, joist hang 2×6 #2 24 inches on center.

In any case, raised heel trusses should be utilized to allow for full depth of insulation from wall-to-wall. https://www.hansenpolebuildings.com/2012/07/raised-heel-trusses/
Column depth will be determined by engineer who is designing your plans. They need to be deep enough to go below frost line (not an issue in California) as well as to resist overturning and uplift. Building dimensions, applied wind loads and soil bearing capacity will all impact depth of holes.