Steel Garage/Shed….Mountain Climate
mhomedream
| Posted in General Questions on
We are putting up an all steel building to serve as a storage shed/garage in a mountain climate with lots of snow. There will be a concrete slab with stego vapor barrier and no electric/plumbing. We will not be there most of the year to monitor things. What are steps we should take to ensure that are belongings stay safe/dry? Would ridge vents be helpful or harmful? Insulation? Where and what type(we cannot use spray foam). We’re leaning towards less is more because a tight building without ventilation seems like a recipe for disaster but I’d love to hear feedback. Thank you.
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Replies
Sound like a great place to keep a tractor out of the weather but a lousy way to build a home.
I am not sure if you plan is one the other of both.
Will you need conditioned living space some or all of the year and what percentage of the time?
With a steel building the only affective place to locate your insulation is on the exterior.
If the plan is mostly unconditioned space, then you could build a tight well insulated building inside your drafty poorly insulated steel shell.
It is a harsh reality that every penny and more you saved by buying the low-cost steel building will be wasted if you chouse to heat and cool the building. Virtually every part of a steel building will be upgraded should you chouse to make it an energy efficient living space or you will spend it on fuel if you dont.
Tight well insulated spaces generally do not do well without conditioning.
I like the idea of buying used RV and keep it in your barn for the living space you want. It was purpose built for the use you discribed.
Walta
Hi Walta,
Thanks for the reply. This space will remain unconditioned and is strictly for storage. Our concern is that moisture from 'sweating'/condensation would be enough to cause mold growth in our RV. And fwiw nothing is low cost anymore. This shed will be WAY over 6 figures. Am I correct then that no insulation is the way to go? No ridge vents? Just a vapor barrier and the steel?
You don't want a vapor barrier anywhere in your walls or roof. Avoid the common bubble wrap under metal panels as these are true vapor barriers and provide next to no R value.
What you want is a simple vented structure. The walls should have house wrap under the metal and the ceiling should be metal over plywood or strapping with synthetic underlayment over the wood. The underlayment here is important as it will contain the night time condensation on the back of the roof panels and keep it from dripping on equipment. I haven't tried it but you can also get metal panels with a felt back that also work the same.
Without a heat source you will still get condensation on equipment inside the shed in the mornings. There is no way around this without insulating/air sealing/heating the place.
Sorry if I sound a little jaded. Seems like every few weeks or so someone will ask “My pole barn is just completed now how do I make it energy efficient to heat and cool.” There is no good answer to their question.
Since the plan is unconditioned storage, I say well vented is best option. Continuous ridge vent and an equal number of square inches of vent 24 inches or so above grade high enough so that rain will not splash on the ground and get in the vents. Consider getting some translucent roof panels for lighting.
Yes, if you have something like a cast iron table saw in the barn and it has been below freezing for weeks and a spring warm front blows in and it goes from 20° to 70° in 18 hours. The tables saw will be cooler than the dew point of the air in the barn and water will condense on its surface and is unavoidable short of conditioning the space.
Most steel building run about $25 a square foot plus the concrete floor. Must be something big or special to cost so much care to tell us about it.
Walta