Insulation for a post frame building with radiant floor heating

[Husky79]

Me and 2 of my friends are starting up a business on a land we purchased together. The building is going to be a 40'x104'x10' and it will have 3 sections, one 40'x24' for living/office, 40'x24' for shop/prep room, 40'x56' farm building (aquaculture) . Building will not have any overhangs, there will not be any ceiling put in, it will all be open roof where you can see the trusses and roof. The 2 walls separating the sections will be walled all way to the roof and insulated as well too. There will be 3 radiant floor heating zones.

We were planning on to find 93" wide blanket insulation and put that up with no roof vent. Do I put vapor barrier outside around the building and roof before installing the steel panels? Vapor barrier is actually a clear plastic sheet? or is house wrap the same thing?

Since the building will not have roof vents, gable vents, and soffits, is it going to be fine completely sealed? I believe we would need a good dehumidifier for the shop and farm sections as the shop section, we will wash equipment in the shop couple times a month, and farm will have aquaculture tanks, that is going to emit a lot of humidity for sure.

Truss will be common 4/12 pitch truss.

I do wish we could do spray insulation, but that does not fit our budget unfortunately. We have a really limited budget and our goal is to just get the shell up, flooring done, and building insulated so we can start the business immediately.

I forgot to add, the location is north central MN, it gets very cold in middle of winter, we get few weeks of minus teen temps and sometimes for a couple weeks we have minus 20 to 30's.

 

[kabinenroller]

The insulation under the slab and around the perimeter needs to be extreme. A building that does not breathe will have issues with condensation and eventually mold. A pole building is not conducive to in floor heat unless it is very well insulated below, around and above the slab especially in your climate. Cold draws hot so any cold surface will draw the heat and cost $$. You should discuss your project with a local builder who is familiar with the type of building you are planning and it’s use.

 

[billconner]

Kabineroller is correct - at least 2 if not 4 inches of foam under floor and slab edges.

In your climate of R25 in the walls. Fibreglass bv is fine. Vapor barrier on inside - warm side - and house wrap outside. And it should be tight in the wall cavity.

Your trying to do a hot roof. Spray foam is the best choice. If you do into do it that, you need a perfect vapor barrier on inside and probably R40 above that, tight to roof deck. Air gaps there will kill you.

I understand budget and getting opened, but I worry your building could be at its end of life in a few years if you don't solve these moisture issues.

 

[Husky79]

slab will have vapor barrier on ground that goes over 2 inch foam barrier around the perimeter the 2" foam barrier will extend down 2'. After that is done, 2 inch foam on top of the vapor barrier then pex, and rebar go on. It will be 4" thick slab for all 3 sections.

I am only able to fit R19 faced batts for 6" gap between steel wall and interior wall? I would love to get R25, but I have been unable to find any. Monday morning I am calling my local suppliers to find out more on about insulation selection they offer.

Sounds like the safest option is to install vented ridge, install ceiling and do R60+ worth of blow in insulation. Then do 2x6 bookshelf with R19 faced batts for the living/office, and shop/prep room, then do 93" wide blanket insulation in farming section?

 

[billconner]

Sounds like the safest option is to install vented ridge, install ceiling and do R60+ worth of blow in insulation. Then do 2x6 bookshelf with R19 faced batts for the living/office, and shop/prep room, then do 93" wide blanket insulation in farming section?

Yes. That all sounds much better than how I understood your first post.

 

[jack stand]

I'd be very careful about the portion of the building that the aquaculture is in. That's a whole new level of moisture concern that I'd research with a professional or someone already in this business.