Insulation question

YotaOnRocks

YotaOnRocks

Well-Known Member
Joined
Jul 17, 2007
Location
Madison
Getting close to satisfying the county so I am close to pulling the trigger on my new barn.

Barn will be 40x80x16 main section with a 24x80 lean to on each side. Both lean to will be fully enclosed. We will be staying in our camper in the main section, planning to build a play room and full bath inside of the main section to make living in the camper with 2 little ones a little less challenging. Thinking a mini split to climate control these rooms.

There will be 2 14x14 doors in one end of the main section. I am planning on parking our daily drivers inside so one of those doors will be opened several times a day. I have no current intention of adding any climate control to the barn other than the small living area I build.

What type of insulating should I plan on doing?
I know the pole barn supplier uses r-10 r-foil insulation, not sure how much cost it added. Was told spray foam would be $1.5 sq ft, and by my rough calculation that would be about $9600 to insulate the main structure walls and ceilings.

Once our house is built this will serve as a temporary work shop (probably 5 years at least) and a place to house the camper and some of my equipment. Once I build my shop this barn will only be used for storage. I don't want to pay for too much insulation but I also don't want to deal with rusting tools, dripping ceilings and completely miserable humidity if I can help it.
 
CasterTroy said:
Confirm with the county that you can build the building first. Most counties require the HOUSE be build first (to even get an address for permit and power)
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That's been the hold up. First I was told I could, then fast forward to when I'm ready and nope, got to pull the house permits before any secondary structure can be built.

Guy in the planning department told me if I classified it as a farm that I was exempt from the rule and told me zoning could help me. After getting the run around from people who didn't fully understand what I needed to do I found someone that knew.

So I was told to get a forest management plan drawn up and that would classify my land as farm use. I waited 6 months for the forester and got my plan back this month. Went to the county today and I'm good to go except for 1 missing document that my forester isn't familiar with and has no idea what the county is talking about.

Once the forester and zoning guy and myself figure out what magical form is needed they are going to give me permits for power and well. He told me no building permit required for any farm structure only electrical permits would be needed.
 
CasterTroy said:
Confirm with the county that you can build the building first. Most counties require the HOUSE be build first (to even get an address for permit and power)
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They also assigned our address when I applied for the perk test before I even purchased it. I've been receiving mail up there since thr fall of 2020
 
YotaOnRocks said:
They also assigned our address when I applied for the perk test before I even purchased it. I've been receiving mail up there since thr fall of 2020
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That's great!!

That's been the biggest hassle with getting buildings built in NC is the fact that no 2 counties are the same.. and 9 times out of 10 in the same county it's never the same 🙄
Truly depends on the day of the week and which ego driven inspector... Or even secretary... Is looking at your paperwork.

Thankfully most of the problems can be solved with a trip to the ABC store 😎 cept.. the lady you need to grease in Davidson county likes cheerwine memorabilia 🤷🏻‍♂️
 
CasterTroy said:
That's great!!

That's been the biggest hassle with getting buildings built in NC is the fact that no 2 counties are the same.. and 9 times out of 10 in the same county it's never the same 🙄
Truly depends on the day of the week and which ego driven inspector... Or even secretary... Is looking at your paperwork.

Thankfully most of the problems can be solved with a trip to the ABC store 😎 cept.. the lady you need to grease in Davidson county likes cheerwine memorabilia 🤷🏻‍♂️
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You ain't lying. Had me upset when I went down there almost a year ago to get the ball rolling and found out the guy willing to do it without official documents had retired. I don't mind rules, but the first guy left out the part about him bending the rules and the need to act immediately before he retired.
 
You don't want sprayed foam
 
shawn said:
You don't want sprayed foam
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Would you mind explaining, I have very little knowledge/experience when it comes to planning to insulate a structure. I've installed tons of insulation on jobs over the years, but we were provided plans for what and where to put it.
 
Anybody got any input or suggestions?
 
Is this gonna be metal or wood? How is the siding attached? Purlins or nail boards?
 
RR pole barn kit. Wood post frame construction with 2x6 wall girts, only metal is the trusses. Corrugated metal roof and siding with concrete floor.
 
Why not just stick with whatever comes with the kit? Is it ~R10 in the walls and R30-40 in the roof? I can't see that there's a ROI for anything more than that, especially for the size of the building.

YotaOnRocks said:
I also don't want to deal with rusting tools, dripping ceilings and completely miserable humidity if I can help it.
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This is a function of relative humidity (and air infiltration to some extent).
 
shawn said:
Why not just stick with whatever comes with the kit? Is it ~R10 in the walls and R30-40 in the roof? I can't see that there's a ROI for anything more than that, especially for the size of the building.



This is a function of relative humidity (and air infiltration to some extent).
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I am pretty sure it is r10 for roof and walls. I am just trying to avoid any big expensive regrets or mistakes.

My science education is pretty lacking and as embarrassing as it may be for me to admit, the term function of relative humidity required a google for me. All the research I tried to do on insulation just left me more confused and conflicted.
 
Rusting tools and condensation and stuff is just because of water in the air. It's because it's humid. So you need to dehumidify the air that's in the room, keep that air from getting out, and try to keep moist air from outside from getting into the room. There's a related matter of vapor drive, which is the ability of water vapor to move through (otherwise solid-seeming) materials. Water vapor can move through concrete, wood, batt insulation, and lots of other materials. It doesn't move through metal or plastic very well, so you want to be sure there's a plastic vapor barrier under the concrete and that gaps where the metal wall panels meet the floor/soffit/etc are reasonably well sealed. One big benefit of closed-cell spray insulation is that it's basically plastic. It is a very good air barrier and is resistant to vapor drive. The downside is that it's expensive, and if you don't put a sheet of visqueen under your concrete (or put weather-stripping and gaskets on your garage doors or make sure the man doors seal correctly or plug the conduits that go through the exterior walls, etc), you've negated a lot of the benefit and probably wasted a lot of money.

When we talk about relative humidity, it's just that humidity as a percentage of the air is related to the temperature of the air. Warm air can hold more moisture than cold air. Differences in air temperature are what causes rain storms, for example. Cool the air and the water falls out of it.
 
shawn said:
Rusting tools and condensation and stuff is just because of water in the air. It's because it's humid. So you need to dehumidify the air that's in the room, keep that air from getting out, and try to keep moist air from outside from getting into the room. There's a related matter of vapor drive, which is the ability of water vapor to move through (otherwise solid-seeming) materials. Water vapor can move through concrete, wood, batt insulation, and lots of other materials. It doesn't move through metal or plastic very well, so you want to be sure there's a plastic vapor barrier under the concrete and that gaps where the metal wall panels meet the floor/soffit/etc are reasonably well sealed. One big benefit of closed-cell spray insulation is that it's basically plastic. It is a very good air barrier and is resistant to vapor drive. The downside is that it's expensive, and if you don't put a sheet of visqueen under your concrete (or put weather-stripping and gaskets on your garage doors or make sure the man doors seal correctly or plug the conduits that go through the exterior walls, etc), you've negated a lot of the benefit and probably wasted a lot of money.

When we talk about relative humidity, it's just that humidity as a percentage of the air is related to the temperature of the air. Warm air can hold more moisture than cold air. Differences in air temperature are what causes rain storms, for example. Cool the air and the water falls out of it.
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Thank you, that makes a lot of sense to me.
 
shawn said:
The downside is that it's expensive, and if you don't put a sheet of visqueen under your concrete (or put weather-stripping and gaskets on your garage doors or make sure the man doors seal correctly or plug the conduits that go through the exterior walls, etc), you've negated a lot of the benefit and probably wasted a lot of money.
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My understanding is you can also use a good concrete waterproofing sealant to accomplish the same thing if that sheet wasn't put under it.
 
RatLabGuy said:
My understanding is you can also use a good concrete waterproofing sealant to accomplish the same thing if that sheet wasn't put under it.
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The only thing that's going to get you close is an epoxy coating, but that introduces its own problems. I wouldn't recommend in a shop environment.
 
shawn said:
The only thing that's going to get you close is an epoxy coating, but that introduces its own problems. I wouldn't recommend in a shop environment.
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Care to explain? A lot of people use epoxy floors. Slippage?
 
RatLabGuy said:
Care to explain? A lot of people use epoxy floors. Slippage?
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Cost, blistering, burning due to welding/grinding/etc.

Good for a fancy garage to store nice cars, not so much for a 3000sf barn, especially not as an alternative to a sheet of polyethylene.
 
Another consideration beyond the insulation.

I haven’t found a ductless mini split that can be cleaned and serviced properly.

Access and removal of the fan housing and wheel is tedious and difficult, if possible at all.

The inlet side of the evap coil is nearly impossible to get to, to adequately clean.

As well, the filters on these units is just a mesh screen.

This allows debris to accumulate on both the coil and fan wheel, and mold grows on this debris. In addition, the plastic fan wheels create static while spinning, attracting dust particles to gather and stick to the blade surfaces of the fan wheel.

Combine that with the plastic surface allows dust to stick and mold forms quickly in the damp and dark environment.

Galvanized was much better as it is physically slicker on the surface compared to the plastic, as well the galvanizing compound serves well to sanitize the surface from contamination.

TLDR:

Conventional HVAC equipment with galvanized steel and other non plastic components are much easier to service and clean than ductless mini splits. This has a much larger impact on indoor air quality. While there is more work to running the physical ductwork on conventional units, indoor air quality can be far healthier with conventional HVAC systems.


Also don’t oversized the cooling so that the air conditioning can adequately dehumidify the space.

If not occupying the space and you want to control the humidity while not running the air conditioning enough to adequately remove the moisture, consider a permanent dehumidifier to aid in moisture removal while saving energy over running the air conditioner.

For the size of the space, with adequate sealing to prevent outside air intrusion, I would consider a permanently installed 90 PPD unit considering the relatively low moisture load.

Obviously it would take far greater capacity to dry the space if it is filled with humid air, but then just use the conventional HVAC to help dehumidify the space in addition to the permanent dehumidifier.

The current usage difference between a 55/65/70 PPD unit vs a 90/100 PPD unit is relatively small, so the upfront cost difference is the only downside to going with the medium sized units. However, going with a larger 120+ PPD dehumidifier is substantially more expensive with much greater energy use.

Short version: use the smallest dehumidifier that will do the job, and if you need more capacity fire up the air conditioner.

If you need massive capacity dehumidification, run the heat source (natural gas/LP) while also running the air conditioning.
 
shawn said:
Cost, blistering, burning due to welding/grinding/etc.

Good for a fancy garage to store nice cars, not so much for a 3000sf barn, especially not as an alternative to a sheet of polyethylene.
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Especially true considering the cost of the vapor barrier vs the cost of the epoxy.

For that size building, the vapor barrier cost is like sub $200, potentially sub $100 depending on product choice.

That’s ridiculously inexpensive compared to any type of concrete surface treatment.
 
RatLabGuy said:
Care to explain? A lot of people use epoxy floors. Slippage?
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I'd rather keep the moisture trapped beneath the slab than in the slab itself. Plastic under the slab is preventing a problem, seal coating to hold out moisture from below is trying to cover up a problem
 
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