Tag Archives: insulating a pole barn

Avoiding Condensation When Insulating an Existing Pole Barn

Avoiding Condensation When Insulating Existing Pole Barn

The last thing people want to have to deal with would be condensation dripping in their pole barn. When an originally unheated cold storage building becomes repurposed to be climate controlled, possible condensation poses some new challenges.

If you are reading this article and plans are to construct an unheated building, I implore you to consider taking steps so it could be repurposed to be heated and/or cooled later. Please browse through some of my previous articles regarding this subject, such as: https://www.hansenpolebuildings.com/2018/06/pole-barn-insulation-oh-so-confusing/.

Reader JOSEPH in ALPINE writes:

“We have a pre-existing pole barn that we want to turn into a insulated building. Knowing that condensation would be a problem, I’m looking for a professional to consult with so it is done correctly. Is this something you do and what are your rates?

 

The building is 15×15, on a pad. There is no attic- 1/4” plywood is nailed to the ceiling 2x4s. We’d like to keep this height since it affords space for a loft. There is a single central roof vent. I read your response to one customer about using unbatted insulation on the walls and punching holes in the plastic to allow venting. But how does one allow for venting when there is no attic space? Our main house (1937 farm home, remodeled to modern code in 2003) is a metal roof with the upstairs rooms opened up, no attic, no roof vents. How can one replicate what is done in the house with this pole barn?

Thanks.”

Mike the Pole Barn Guru writes:

I am deeply flattered to have someone offer to hire me for a consultation. Here is my response to Joseph:

I am a bit geographically inconvenient to be able to come and see your building. However, based upon experience and what I would do if it was my own building, I will give you some free advice. You are welcome to use it, or discard it as best you see fit.

As you do not know if a vapor barrier exists beneath your existing concrete slab, I would use a high quality surface sealant over it. Your major water source for potential condensation will be through this slab. I’d close off roof vent, and have inside surface of siding and roofing closed cell spray foamed. Your local installers can give you recommendations for thickness, however I would not go with less than two inches thickness. If possible or practical, unfaced fiberglass insulation may be added to the inside to increase R value. However, it might be most practical to just pay a little extra for thicker spray foam.

 

 

Insulating an All Wood Gambrel Barn

A reader writes: “Dear Guru.I have an all wood gambrel style pole barn that I’m converting to a shop.  I’ve installed forced air heat and am getting ready to insulate.  My exterior walls are Tyvek wrapped osb and vinyl sided.  I am wanting to use rigid board to help deter rodent nesting.

  My questions are: for the walls should I cut and fit 1 1/2 inch board to fit all of the spaces between my girts before I layer rigid over the girts or can I layer over the girts to start?   The ceiling I was planning on installing 2″ rigid on top of the 2×4 truss bases and then applying a closed cell poly “Prodex” brand white faced on the bottom leaving the 3 1/2 inch air gap between the two. Prodex is claimed to be r16 and the rigid r10. Or is there a more suitable way to do the ceiling like cutting board to fit between said trusses and using Prodex on bottom with no air gap?  

 Thank you for your help.  I’m finding hundreds of articles and advice on metal buildings which mine is not and trouble finding a solution for my project.  Oh, and I live in northern Ohio”

Good move having Tyvek in your walls to prevent weather from seeping into your insulation cavity. If your walls are tightly framed (which they should be) the possibility of rodents getting into your wall cavities should be zero. Cutting and fitting insulation board to fit between framing members sounds like a mountain of labor, as well as pretty near impossible to be able to get a tight fit against every stud. I’d be inclined to use either closed cell spray foam insulation or BIBs insulation for walls.

Prodex is a radiant barrier and your chances of getting a measurable R value out of it more than one and change is not good. In a thorough 2010 study by the Canadian National Institute for Research in Construction, their conclusion: In a perfect state (with no dust on the surface), a radiant barrier with an air gap increased the efficiency of insulation in a wall by 10%. In other words, if the wall was already R6, adding ‘miraculous’ foil bubble wrap added .6, for a total of R6.6.

The best way to insulate your ceiling is to blow in cellulose or fiberglass to at least R45, if not R60. Do not place a vapor barrier under blown in insulation. Make sure the attic space above the insulation is adequately vented.

 

Mike the Pole Barn Guru

Attic Insulation Guide

Pole Barn Guru BlogWelcome to Ask the Pole Barn Guru – where you can ask questions about building topics, with answers posted on Mondays.  With many questions to answer, please be patient to watch for yours to come up on a future Monday segment.  If you want a quick answer, please be sure to answer with a “reply-able” email address.

Email all questions to: PoleBarnGuru@HansenPoleBuildings.com

DEAR POLE BARN GURU: I am building a 24’x32′ pole barn type shop using 5 clerestory trusses in which I will install windows in the verticals for natural light. I want the roof shingled and insulated. Is there a way to frame in roof rafters between the trusses to carry the weight of the roof sheathing and to use batt insulation underneath? SCOTT IN ELLERSLIE

DEAR SCOTT: For sake of discussion, we will assume the trusses have been engineered to carry the weight of all of the materials you will be adding.

In order to use batt insulation as you propose, Code requires there to be at least a one inch air space between the top of the insulation (which must be unfaced) and the underside of the roof sheathing. This space must be vented at eaves and peak, and airflow must not be impeded.

Just off the top of my head (and knowing nothing about how your trusses are constructed), I’d probably look at placing a header at the eave and peak, which would carry 2×12 rafters placed every 24 inches and running the same direction as the trusses. Insulation batts up to 10-1/4 inches thick could then be placed between the rafters.

You should consult with the RDP (Registered Design Professional – architect or engineer) who designed your building, to confirm sizes and connections of members, as well as their adequacy to carry the imposed loads.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: My name is Ben, and my husband and I plan to build a timber pole house in the mountains around Luray, VA. We are still in the planning stages, but are already working on the design stage of the house. I wanted to reach out and see if you offer the type of services we need, even though your website seems like you would be just perfect.

As a quick summary of our needs:

I am a 3d artist and am laying out the space in 3ds max to get an idea for room size, arrangement, and other proportions. However since I am not an architect, I need someone to go over the design, make it useable, point out any problem areas I am unaware of as a non-architect. Also being able to get all the materials cut and shipped to our building site is a huge plus.

Additionally, as we are still researching land, I would like input on what to look for based on our design, and then after land is procured, any adaptations needed for our plan to fit the space (the biggest thing I am worried about, is pile depth for the timber piles to pass code and be structurally sound). We plan on a 2 story building, so it’s likely the max timber height above ground would be around 35 feet for some of the timbers. We also plan to build on a mountain side, so the timber length would vary.

Is this the kind of service you can offer?

Thanks so much for your time,  BEN AND AGUST IN LURAY

DEAR BEN: We can supply columns up to 60′ in length, so you should not have any difficulties with what you have in mind – nor will needing various lengths be a challenge.

Our designs do not incorporate interior non-load bearing walls, as we have found room sizes tend to change greatly once the exterior shell is up and clients get a much better feel for what each room will do, as well as for orientation. Always try to work from the inside out – determine (at least close to) the area of the spaces you will need and then orient these spaces to be most functional for your lifestyle. Then create an envelope which fits around your spaces.

The ultimate location may (and should) play a great deal into the final design. Orientations should be such to take advantage of the most practical approaches to the site, as well as views and exterior living spaces (decks and patios).

Keep in mind – any pricing done now, is based upon where markets are at today. Lumber and steel are commodity items and prone to a great deal of variability which is beyond anyone’s control. Allow plenty of safety cushion in your budget, it is always a pleasant feeling to have more money left over, than having to scramble because things were planned too tight.

Mike the Pole Barn Guru

DEAR POLE BARN GURU: I am interested in pricing for a pole barn/apartment.  I am selling my house and will be purchasing roughly 15 acres of land.  I would like a pole barn constructed on the land.  I intend on building my own home which will take some time.  I would like a two story pole barn, with the upstairs being the finished apartment with somewhere around 900 square feet so I can live on my property while my house is being built.  Is this something that you would be able to do?  Thanks for your time. JEFF IN CINCINNATI

DEAR JEFF: Thank you very much for your interest in a new Hansen Pole Building. We provide post frame (pole barn) building kit packages similar to what you have in mind on a regular basis. You will be contacted shortly by one of our Building Designers to get more detailed information as to your exact needs.

Mike the Pole Barn Guru