Exactly!

 

It did a big commercial bldg. I worked in one time , then the spray foam started falling off--------jfi

 

Yes , as long they are on 24/7 . THat will stabilize the moisture content allowing you to control the humidity

 

Im hoping that was years ago. There weren't many guys applying it, or even certified to do so.
The products in use now seem to be pretty damn good, plus the application process has evloved.

 

The fiberglass, thick plastic skinned ins. that bldg. companies install has proven to be the best around here , working in and out of and on those bldgs for 52 yrs. influences my opinion ------

 

Yes!!
Too late for thick plastic underneath the concrete.

 

Yes. Between can work, but it will have multiple drawbacks. Heat will be conducted in/out by the metal framing, but worse it will allow condensation to form at the edges of some of your insulating panels. This can draw bugs and mold etc.

One sealed envelope will help seal the wind out and will also be a neater install in my opinion.

 

Pole building 40x60x12 that bubble wrap under the metal siding and roof. 6x6 beams 8 ft on center. I put 2x6s 4 ft between beams then used 6” thick fiberglass battens 24” wide stapled together to make 4ft then 1/2 osb ply over that osb in the ceiling but no insulation up there yet. Still get a little moisture in the summer so I’m thinking of some type of air flow (no windows) 80 thousand btu oil furnace and two 110 ac window type units on each end of building. I can keep it 70 year round in Va

 

Everything in life is a compromise, LOL. Anything will be better than nothing, just take as much care on the details as you can manage.

 

cut the rigid boards and stuff them between the uprights then foil tape the seams , if you make them tight enough no need to fasten them in place . same for the roof then screws with large washers into the purlins ...done , easy peasy

 

When my pole building was built the contractor installed either 1/2” or 3/4” foil covered styrofoam between the wooden frame and the metal sheeting and fiberglass with foil backing between the rafters and the steel roofing. There is a vapor barrier under the concrete floor and the floor is sealed. I have no issues with moisture and plan on upgrading the insulation and installing a HVAC sometime in the future.

 

Another option is to space the boards away from your siding which would add an air space and the rigid boards themselves would not come in contact with the siding and condensation. Your roof has the purlins which will give you a 1¨ air space . Unfortunely due to the horizonally mounted siding you have no purlins on the vertical walls . After you cut your fitted boards you can glue several approx 4-6¨ strips of excess board material to the back of your fitted boards to give you a 1¨ air gap.

 

You'll want a layer of foam over each exposed metal member, otherwise those cold beams will still sweat inside.

The idea of leaving a gap and securing directly to your framing is a good one, but the air space will act more like a "rain screen" and won't necessarily make the wall better insulated.

Since you have surface mounted electrical, I'd stick to your plan of going between beams (and overlapping a second layer over each beam). Later on you can add another layer and a few years later another layer... Etc.

Don't bother with the interior vapor barrier. The foil facing of the foam will act as one already (usually) and having the ability to diffuse any random moisture is still a good thing. Some sort of durable wall board would be a good idea to protect the foam boards. Plywood, osb, hardboard, drywall, concrete board, doesn't matter a ton, but any all-wood materials are at greater risk for fire than drywall (which actually produces moisture/water as it gets heated) or concrete board.

Since drywall sucks up standing water and is easily damaged, I like thin cement board for the first 4' or so of a garage wall.. But that's just me.


Another option would be to layer metal siding on the inside.. Durable, easy to replace, no mud or mortar to install it and can be taken down to augment your insulation in the future. Also less prone to fire/burning. Even corrugated metal roof panels could be used, even if only partially sheathing the wall.

Just my $.02

 

Rain shield or rain screen is a term used to describe an exterior cladding that has an air space behind it. In contemporary construction it's done to prevent trapping rain or condensation between the cladding and the exterior sheathing or wind barrier. It can act as a radiant barrier space and also a thermal gap to prevent conduction from the framing to the exterior. The draw back is that it gives bugs a great hiding place and makes a wall assembly thicker for not a lot of gain in true insulation performance.

The weight of any interior wallboard is good to keep in mind. A sill plate could be bolted to the foundation and used to support the weight of the wall off the framing. Use good pressure treated lumber and it should last plenty long enough. As long as you're not framing a lumber wall to hold the interior sheathing, the slab should be sufficient to hold up the dead load it may impart. Metal siding would likely be the lightest per square foot and drywall (1/2 or thicker) the heaviest. You can look at lightweight drywall too, which is easier to handle if nothing else.