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Wall Insulation for a Hybrid Building

Wall Insulation for a Hybrid Building

Reader MASON in HILLSBOROUGH writes:

“I read your blog often and I truly appreciate the wealth of knowledge you openly share. I am in the process of starting construction on a hybrid steel shop that will house a small apartment that the wife and I will move into once its finished. We will sell our current home and then build a smaller house adjacent to the shop. 50 X 80 with 24′ wide mezzanine on one end. My questions are centered around wall/roof construction as well as proper insulation. Roof: I plan to install a standing seam roof with ice/water shield over 5/8 plywood. As you are aware, with hybrid steel it is hard to ventilate the roof with this type of construction. This downfall didn’t outweigh some of the benefits so this is what I am stuck with. Would like to understand some insulation options. Note: I do have the building designed to handle the loading of a couple of cupula’s and have considered making these passive and active ventilation points. (Exhaust fans with some louvers that I have yet to get the details figured out on)Walls (2 options): (Note: I prefer not to plan or have to always be fully conditioning the shop to 72 degrees…..I plan to have that ability by mechanical means but I don’t want to consistently have to be conditioning that much space, therefore I think i prefer the building to be able to breath out to the perimeter. I realize this may be tricky between the roof type and wall type)Option 1: metal siding – would like some input on wall and insulation construction based on the above notes of conditioning. Option 2: Hardie board vertical board and batten walls. Same as above, would like your input. There will be components on the first floor and second floor that make up the apartment space. Our approach on insulation and wall construction may change within those enclosed spaces may vary as they will be conditioned separately from the open shop space. Hope you can help shed some light on this approach and again thank you for your time and knowledge. Thanks!”

Thank you very much for your kind words!

In Orange County, being Climate Zone 3A, I would most often recommend drying to inside, using closed cell spray foam to insulate underside of roof deck and applied directly to wall steel. This does entail having to mechanically dehumidify.

Given your desire to dry walls to exterior, here are my thoughts:

Have a well-sealed vapor barrier under your slab on grade – you want as little moisture as possible entering building.

Include eave overhangs of at least two feet – this is again about moisture. You want to push weather (water) away from base of building.

Install continuous gutters, draining at least 10 feet away from building foot print.

For wall construction – regardless of siding being used, place a drainable housewrap under siding (make sure it is omnidirectional, so you can install either vertically or horizontally). Use bookshelf wall girts to minimize deflection and create an insulation cavity. Unfaced Rockwool insulation to completely fill insulation cavity. Well-sealed interior vapor barrier.

This entry was posted in Ventilation, Building Interior, Insulation, Pole Barn Heating, Pole Barn Questions, Pole Barn Design, Barndominium, Pole Barn Planning and tagged gutters, close cell spray foam, vapor barrier, housewrap, wall insulation, post frame insulation on May 28, 2024 by Rick Ochs.

Ballpark Figures, Blueprint Costs, and Condensation Drip

This Wednesday the Pole Barn Guru answers reader questions about ballpark figures to estimate costs of a barndominium, the costs for blueprints for a 40x60x20 building, and what the best way to stop condensation drip on a post frame building would be.

DEAR POLE BARN GURU: I’ve got a very general question, hope you can help. Is there a very ballpark figure for estimating a barndominium? As in square foot to dollars. My current house is 2500 sqtf. on two acres. I’d like less house on larger property. Currently negotiating with a friend for 7 acres. Need a ballpark figure on construction in order to decide if it’s just a pipe dream. Thanks JIM in MONEE

DEAR JIM: Thank you for reaching out to me Jim, message me any time with questions. Fully engineered post frame, modest tastes, totally DIY, move in ready, budget roughly $70-80 per sft of floor space for living areas, $35 for all others. Does not include land, site prep, utilities, permits. If you hire a General Contractor to do everything, expect 2-3x as much.

DEAR POLE BARN GURU: I’m looking to some blueprints for a 40x60x20 pole barn it will have 2 10×12 doors on the gable end wall. I want a 2 foot over hang. I want to sheet the roof with 5/8 cdx and walls with 1/2cdx. How much would the blueprints cost? MICHAEL in COOS BAY

DEAR MICHAEL: Thank you for reaching out to me Michael. Our engineers will only seal plans when we provide the materials, as it is the only way they can guarantee materials they specify will actually arrive onsite. Please send your specifics to Caleb@HansenPoleBuildings.com along with your site address and best contact number. You will find we are very competitive and have provided hundreds of fully engineered post frame buildings to our clients in Oregon.

DEAR POLE BARN GURU: Hello, I asked an insulation question on social media and it quickly turned into a debate among other members. In your opinion is there any way to stop the condensation drip on a porch we would like to cover with T/G, box in with soffits? This is a new post frame building with an offset porch. Initially we planned to leave framing exposed but due to birds and wanting a more finished look we would like to put a ceiling in place. Thank you. MEL in ISLAMORADA

DEAR MEL: As it is already existing, your quickest and easiest is to do 2″ of closed cell spray foam directly to roof steel underside.

This entry was posted in Ventilation, Budget, Insulation, Pole Barn Questions, Porches, Pole Barn Design, Building Overhangs, Pole Barn Heating, Roofing Materials, Constructing a Pole Building, Pole Barn Planning, Barndominium, floorplans and tagged spray foam, estimating a barndominium, engineered post frame home, pole barn costs, blueprints, engineer sealed plans, close cell spray foam, condensation on March 13, 2024 by admin.

Insulation, Insulation, Insulation

The Pole Barn Guru discusses the always popular ceiling insulation, vapor barriers with insulation, and closed cell spray foam insulation.

DEAR POLE BARN GURU: I read your article on unvented roofs. My building has a vapor barrier installed. I am at the point of insulation and plan on doing closed cell spray foam. What would be better spraying the roof deck or the attic floor/ top side of the ceiling. I was thinking spraying the roof deck and then doing blown in insulation above the ceiling to get my r value. I thought having the entire building done in closed cell would make for the tightest building. BRAD in FLANAGAN

DEAR BRAD: If you have a condensation control barrier (having a thermal break, not just a vapor barrier) of some kind between roof steel and framing, then there would be no need to closed cell spray foam underside of roof deck, unless you are going to use this as your only insulation. Insulating ceiling line creates a dead attic space above, so it will need to be ventilated (either eave and ridge or gable vents). Closed cell spray foam will give you a very air tight building, applied properly.

DEAR POLE BARN GURU: Built pole barn installed 1-2 inch thermal sheathing in outside installed 8 inch batt would you install vapor barrier on inside been told I have two vapor barriers answers. JIM in HARTFORD

DEAR JIM: You are going to have insulation sandwiched between two vapor barriers, however air leakage into the cavity is a greater issue than through a vapor barrier. Goal is to keep insulation and wall framing dry. As long as you adequately seal all of the air leakage pathways you would not need an interior vapor barrier. In other words – if you install an electrical outlet or switch box, seal it, seal around any door or window openings.

DEAR POLE BARN GURU: What do you feel is best insulation system for pole buildings building we got is 162 x 72 wood structure built on foundation wall columns on 6 ft on center girts nailed to outside of columns and also inside corrugated metal we installed 1/2 poly iso insulation and 8 inch batts in wall spray foamed base to seal air leaks and plugged holes on top with 3 inch iso between columns and foamed around window frames poly iso has foil face and we taped seams wanted to install poly vapor barrier on inside but was told that I would have two vapor barriers which is bad what do you recommend? JIM in HARTFORD

DEAR JIM: My recommendation would be two inches of closed cell spray foam on inside of steel siding. Install another set of girts on inside of columns to support interior wall finish material. Fill wall cavity with BIBs (https://www.hansenpolebuildings.com/2011/11/bibs/). Glue two inches of closed cell foam insulation board on inside of girts, sealing around any penetrations. Glue interior finish material to inside of insulation board.