This week the Pole Barn Guru addresses the need for a vapor barrier as well as some framing recommendations in a future build, the possibility of a Gothic Arch truss design with glulaminated columns, and the addition of a “lean-to” to a 2016 Hansen Building.
DEAR POLE BARN GURU: Hello Mike, Our monitor style home has been designed by your staff and we are putting together financing and logistics details edging closer to ordering our materials package. Still a bunch of questions to ask of the Guru. We will be using an AIB under the steel siding with rockwool insulation in the cavities. I believe we will need a vapor barrier on the inside. I will be working alone on a lot of this construction and don’t look forward to wrestling with plastic sheeting for our vapor barrier. I would like to use a rigid insulation board such as r-tech or r-max with taped seams to accomplish this. I’m thinking it will much easier to seal electrical boxes and such with something rigid. What’s your take on this approach? Do you feel it is a safe and effective way to accomplish this? Thanks as always for your great information! RUSS in TILGHMAN
DEAR RUSS: Yes, you will need a vapor barrier on inside. I have suggested this very same solution more than once, as it looks like both reasonable to install and a way to minimize thermal transfer. I would recommend windows and door openings in commercially girted walls be framed out with one dimension larger members (2×10 rather than 2×8) and use 2 inch insulation boards, for ease of attaching finish trims on interior. You might also want to go with 2×8 treated bottom plates, for this very same reason. Insulation boards can be taped to these one size larger members.
DEAR POLE BARN GURU: Looking to use laminated Gothic arch design trusses, 4 foot on center anchored to 1st floor continuous floor trusses 16 inch on center with two rows of support beams at 12 foot under floor trusses. 2nd floor planning on recreation and residential area. Need to have plans drawn up to meet codes. Would this style post framing be sufficient for truss kick out using a truss bass shoe and steel gusset plate at ridge? Possibly add some knee walls at 1st floor framing for added support. Help me out, kinda designing on my own until I get prints. Thanks, ROGER in SOUTH HAVEN
DEAR ROGER: At one time I had actually acquired a set of plans for an old Gothic arch design. Tried to get them to engineer out and regardless of what lumber was used, could never get them to work. It might be possible to have glulams made to conform to your arch form, however I fear it would be phenomenally expensive. Should you be determined to follow this path, I would recommend you reach out to Travis at MSS Engineering (260)267-7414. He is registered in Michigan, and if anyone can make it work, it would be him. Best of success in your endeavor.
DEAR POLE BARN GURU: I purchased a 24′ x 36′ pole barn from Hansen in 2016. I has an 8′ lean-to on one eave side making its total dimensions 32 x 36. I would like to add a 10′ enclosed lean-to on the other eave side. Since my building is one of yours, can you design and price it with the same siding colors and account for snow load and the pitch of the new roof? KEVIN in FORT WAYNE
DEAR KEVIN: Absolutely we can assist you with this. One of our Building Designers will be reaching out to you Monday to discuss further. If you have enough available space, you may want to consider coming out 12 feet, as your investment will be very similar.
Most often steel truss post frame kits are being sold as ‘roof only’ structures – in order to drive prices down. I have seen some great prices advertised, however as prices get lower, so does usually quality and or service. Things tend to be not included, such as trims and condensation controls. Most of these buildings are not engineered, other than maybe trusses. However, even your best steel truss engineering is negated if quality controls are not present at wherever they are being manufactured. Use of steel of a lesser grade or thickness than specified can compromise strength. Pre-manufactured trusses are supposed to have in plant quality control and random quarterly third-party inspections, having spoken with a few of these (in hopes to find a reliable provider of steel trusses) – none of them appear to be aware of this requirement. Steel trusses should also be fabricated by certified welders. While I am sure there are some great steel truss providers, they are seemingly difficult to find.
My recommendation would be to use wood trusses. If you are trying to gain interior clear height, wood trusses can closely mimic what steel will do. Wood trusses are far easier to finish overhangs and if you want to have a ceiling finished at bottom chord height, wood trusses make it very easy to achieve. Wood trusses are subject to extremely stringent quality control standards. Every set of trusses we manufacture has to have extensive records kept to verify accuracy of members and connectors, plus – we have third party inspections.
For columns to be mounted into ICC-ESR Code conforming wet-set brackets there are other alternatives. Standard glulams for construction typically have a Fb (fiberstress in bending) of 2400 pounds per inch. This compares favorably to familiar pressure treated lower glulams, where most have a Fb rating of roughly 1900.
