OT - Shop insulation

[50BMG DUDE]

Hi guys,

Looking for some ideas on how to (better) insulate a steel building. I built a new 8,000 sq/ft steel building 2 years ago. They sold me a fiberglas insulation package with white ripstop plastic glued to it. Trouble is, I'm in North Idaho and the insulation value is only R-13. Costing me a fortune to heat the shop. Looking to add insulation to the roof at least for now. Problem is it's a operating shop and PACKED with machinery. no room at all for scissor lift access to entire roof. Sidewalls are 14', peak is about 21', 60' wide building

Possible solutions
- Spray foam is obvious, but REALLY expensive up here (About 1/2 what I paid for the building) - Also don't like the way it looks, especially in a machine shop with coolant and weld smoke in the air. Quoted cost about 30K - net R-value gain about 10-15 points I'm told
- Blue Foam board, Could cut to 24" panels and install between the purlins, Estimated cost about 10K, Net R-value gain about 11 points
- Steel sheet the inside of the purlins and blow in cellulose. (I have 6" purlins), would be a PITA to blow each space individually. - Unknown R value gain, Estimated cost 10-15K

Wondering if anyone knows of a ridgid insulation that would have a surface coating that's not butt ugly and doesn't cost more that 15K to do 8K

Help please, just spent $1,600 on propane for the last month...

 

[DDoug]

1. Piecing in foam panels doesn't address the cold coming thru the steel framework & purlins.
2. Anything spray applied will have to stick to that crappy vinyl that's already up there.

 

[Overland]

Seems to me that any of the systems you indicated above would have the same issues with access over the machines. Maybe one of those manlifts with a boom so you could reach out over the machines.
The purpose of the vinyl is a vapor barrier. If you add more insulation over it you may get condensation on the vinyl you've buried, and that might be a problem.
Decide what level of insulation you need, then look at the value per inch of the options;
fiberglass is about R3 per inch, styrofoam might 4 or 5 etc.
Sounds like you have about 3 to 4 inches of fiberglass now, so not much room left between the purlins. Maybe best would be plain fibreglass matt to fill out space between purlins, then cover everything with another layer of perhaps 4" vinyl faced, adding maybe 16 to your existing R-value, for a total of about R30. Add second layer parallel to ridge line.
Attaching this to your purlins maybe a problem though, you may need to attach some simple blocks to the purlins to create space for the fiberglass, and a place to attach metal strip. It is normally held in place by long strips metal, maybe 3/4" x 16 gauge that run full length.
There are many specialized fiberglass insulation companies, that will cut rolls to your width and thickness.
Don't forget to consider whether burying that vapor barrier will cause a problem or not.
I used this company and found them very good, with the best pricing.
Good luck,
Bob

Locations

bayinsulation.com

 

[Hobby Shop]

Unless I’m missing something 6” fiberglass batts between purlins would give you R-20. Unless there’s a waterproof barrier under the metal, cellulose and metal roofs don’t mix. You’ll lose R-value over time because the condensation drips will flatten it out.

 

[BT Fabrication]

gonna be expensive either way. guessing steel engineered I beam. Only way to spend less $ is to have a smaller area to heat or reduce the heat losses by adding more insulation. Spray foam works best due to it not allowing air to pass through it. then you can always sheet over top to cover it all.
with the price of propane, im not surprised at the cost. 1300 sq ft here and its kept in the mid 40's and is still $30 a month min.

 

[gustafson]

Air leaks
Dollars to Donuts you are losing more heat through air leaks than through the insulation.
Overhead doors can be made fairly airtight with enough effort.
Also those Reznor heaters conveniently hung up out of the way do a really good job of heating the ceiling but the air stratifies and it is 60 degrees at the floor and 80 at the ceiling, so you are paying to heat your building to 80 and only getting 60. Ceiling fans are one answer but also forcing the heat straight down to the floor in the first place is even better.

 

[kustomizer]

Our building is 1/3 the size of yours, when all was said and done we had 35k in insulation. The first 3k was a 40 foot trailer load of poly iso, 3-5 inches thick, they were factory seconds with odd thicknesses. !/2 of them had mismarked OSB on one side, we matched them up so when 2 layers went on the ceiling, they added up to about 8". I bolted a bunch of 2x4's to the frame to attach the insulation to. I cant find pics of the poly iso on the big building, 16 foot ceilings but here is one of the smaller building with the first layer up and the second one started.
Both our buildings have attic space and we put 4" of closed cell spray foam on top of the poly iso. We put 5" on the walls then covered them with roofing metal for interior walls. Much of the work was done over and around the machines. We heat 3400 sf with a 75,000 BTU propane furnace or a 80,000 BTU oil fired depending on which is more economical for under $200 last month on oil, I just added the propand and turned it on a few days ago so we will see but I expect it to be about half the cost of oil right now. We are a bit south of you but the temps are similar most days.

 

[FredC]

Quote "They sold me a fiberglass insulation package with white ripstop plastic glued to it."
Was this insulation put up before the outside sheet metal? If so it does break the metal to metal contact and is a plus. On my building (60 X60) we did this then put 6 inch batts under the sheet rock. Roof also had the same vinyl coated fiberglass between the red iron and sheet metal roof. Also put in a suspended sheet rock ceiling with 6 inch glass batts on it. Pretty happy with the results, but here summer heat is more of an issue than winter cold.

If you cannot afford to do it all at once start with your north wall and ceiling/roof first.

A link to an older thread on this same subject, this older thread was resurrected a couple of weeks ago with newer comments: https://www.practicalmachinist.com/forum/threads/insulation-for-steel-building.276319/

 

[50BMG DUDE]

Seems to me that any of the systems you indicated above would have the same issues with access over the machines. Maybe one of those manlifts with a boom so you could reach out over the machines.
The purpose of the vinyl is a vapor barrier. If you add more insulation over it you may get condensation on the vinyl you've buried, and that might be a problem.
Decide what level of insulation you need, then look at the value per inch of the options;
fiberglass is about R3 per inch, styrofoam might 4 or 5 etc.
Sounds like you have about 3 to 4 inches of fiberglass now, so not much room left between the purlins. Maybe best would be plain fibreglass matt to fill out space between purlins, then cover everything with another layer of perhaps 4" vinyl faced, adding maybe 16 to your existing R-value, for a total of about R30. Add second layer parallel to ridge line.
Attaching this to your purlins maybe a problem though, you may need to attach some simple blocks to the purlins to create space for the fiberglass, and a place to attach metal strip. It is normally held in place by long strips metal, maybe 3/4" x 16 gauge that run full length.
There are many specialized fiberglass insulation companies, that will cut rolls to your width and thickness.
Don't forget to consider whether burying that vapor barrier will cause a problem or not.
I used this company and found them very good, with the best pricing.
Good luck,
Bob

Locations

bayinsulation.com

When we put the shething steel on, I think we pulled the insulation too tight as well. It probably only ballons to 2" thick max in the center of the 24" spaced purlins. At the purlins it is smashed flat by the sheathing, so there can't be crap for insulation there.

I really wish I'd have stick framed instead.

 

[50BMG DUDE]

Air leaks
Dollars to Donuts you are losing more heat through air leaks than through the insulation.
Overhead doors can be made fairly airtight with enough effort.
Also those Reznor heaters conveniently hung up out of the way do a really good job of heating the ceiling but the air stratifies and it is 60 degrees at the floor and 80 at the ceiling, so you are paying to heat your building to 80 and only getting 60. Ceiling fans are one answer but also forcing the heat straight down to the floor in the first place is even better.

I have hot water in floor heat in the shop.

Trying to get a Outdoor wood boiler to help mitigate the costs but they are 6-8 month wait.

I have 2) -12' Big ass fans

 

[50BMG DUDE]

Our building is 1/3 the size of yours, when all was said and done we had 35k in insulation. The first 3k was a 40 foot trailer load of poly iso, 3-5 inches thick, they were factory seconds with odd thicknesses. !/2 of them had mismarked OSB on one side, we matched them up so when 2 layers went on the ceiling, they added up to about 8". I bolted a bunch of 2x4's to the frame to attach the insulation to. I cant find pics of the poly iso on the big building, 16 foot ceilings but here is one of the smaller building with the first layer up and the second one started.
Both our buildings have attic space and we put 4" of closed cell spray foam on top of the poly iso. We put 5" on the walls then covered them with roofing metal for interior walls. Much of the work was done over and around the machines. We heat 3400 sf with a 75,000 BTU propane furnace or a 80,000 BTU oil fired depending on which is more economical for under $200 last month on oil, I just added the propand and turned it on a few days ago so we will see but I expect it to be about half the cost of oil right now. We are a bit south of you but the temps are similar most days.
View attachment 380228View attachment 380229View attachment 380230View attachment 380231View attachment 380232

WOW -That's really nice, Should be able to heat that with a Bic Lighter

 

[50BMG DUDE]

Unless I’m missing something 6” fiberglass batts between purlins would give you R-20. Unless there’s a waterproof barrier under the metal, cellulose and metal roofs don’t mix. You’ll lose R-value over time because the condensation drips will flatten it out.

There is a vinyl moisture barrier glued to the insulation they provided with the kit. R19 or R21 Fiberglas bats would be great, but short of putting a whole nother metal roof inside I have no way to hold them in place or protect it from dirt/coolant/smoke.

 

[gustafson]

How much foam under and around the slab?

 

[CarbideBob]

- Blue Foam board, Could cut to 24" panels and install between the purlins, Estimated cost about 10K, Net R-value gain about 11 points

I had blue foam board on the walls and ceiling back in the 80's.
We get checked every few years.
The Fire department told me that they would not come inside the building if it on fire until something different on the ceiling.
Bob

 

[gbent]

You just have an insulation starter kit, not meant for an occupied building. There are companies that will take your building plans and build you an insulation package.

On my building, there was 4" installed under the steel sheeting, both sidewalls and roof. It sounds like your building is the same. The 4" seems best, as 6" will make the wall panels bulge noticibly between the screws. Then they installed the interior insulation package. Both the girts and purlins are filled completely with fiberglass insulation, and a vapor barrier is installed over the unfaced insulation. On the walls thin steel strips were installed with projections that would hold the fiberglass in place. The bottom 8' is then covered with the same steel as the outside of the building.

I don't recall the details of installation for the roof insulation, but it is supported by white painted banding below the vapor barrier. The banding is screwed to the bottom of the purlins.

 

[gustafson]

So the formula for heat loss is DeltaT x square feet /R value
you can quickly calculate a gross thermal heat loss for the surfaces of your building. Not super accurate as the R value is not really that simple, but it is good enough for a beer bag calculation.
What it will show you is the diminishing value of insulation.
Your shell probably loses 50k btu per hour at a 50 degree DeltaT
Which is the heat value of half a gallon of propane.
So as an approximation, if you are burning more than that on a say 10 degree day, then it is not a result of heat loss through the insulation. It is though:
air leaks
boiler efficiency
losses in the slab

If you have an 80 percent efficient boiler, you can gain 15 percent by upgrading
Look up 'outdoor reset'
lowering the water temp to the slab when the temperature is warmer results in increased efficiency

 

[Overland]

There is a vinyl moisture barrier glued to the insulation they provided with the kit. R19 or R21 Fiberglas bats would be great, but short of putting a whole nother metal roof inside I have no way to hold them in place or protect it from dirt/coolant/smoke.

My son just insulated his steel building, as a retrofit.
He got rolls of vinyl faced fiberglass to fit between the rafters. This is held up with metal strips about 3/4" wide, 16 gauge, that run parallel to the ridge line, spaced about 3 feet on centers. The edges of the fiberglass have tabs about 3" wide with adhesive tape so that one edge stuck to the rafter, and the other edge overlaps. It's held in place nicely.
If you don't have much depth left between your rafters (or purlins), you can add simple blocks to create space; something like a short piece of metal wall stud just to screw the metal strips to.
This pick shows the bands I'm talking about:

Banded System

bayinsulation.com

Bob

 

[newtonsapple]

How much foam under and around the slab?

Yeah, radiant floor and no description yet of the slab insulation design…

Get someone in there with a blower door and thermal camera. That will let you quickly ID the worst issues. You can also DIY the blower door with a decent floor fan and buy a thermal camera. My library actually has a thermal camera available to borrow in its "library of things."

When running the insulation calcs, you need account for the impact of the steel framing, which is huge:


Looking at the chart, it becomes obvious that what you need is insulation covering the steel. You can do this on the interior or exterior. In new construction, it is often easiest to do this on the exterior. Given you are spending $1600/month on propane and it isn't even cold yet, I think a $20K investment in effective insulation is justified.

This paper has some good assembly examples: https://www.buildingscience.com/file/13592/download?token=s2GGwEU1

Many of the same techniques shown in that paper can be applied to the interior. The goal is a continuously sealed box.

I would look into options for reclaimed or polyiso seconds like what Kustomizer used to be installed continuously over the top of the steel framing. Tape all the seams. Most foam board needs the be covered with a thermal barrier (fire resistant layer) such as 1/2" drywall. Dow Thermax is rated to not need an additional thermal barrier as it is reinforced with fiberglass, which slows how fast it is turned to goo in a fire. Here in the northeast, I can generally get Thermax seconds. It is generally foil faced, although they do make a more expensive white faced version.

Given the operating shop on the inside, I would also consider retrofitting exterior foam on the exterior.

The bat systems can also likely be installed from additional perpendicular framing to allow insulation of the primary steel framing.

* Edit - fixed link to .pdf

 

[50BMG DUDE]

I had blue foam board on the walls and ceiling back in the 80's.
We get checked every few years.
The Fire department told me that they would not come inside the building if it on fire until something different on the ceiling.
Bob

We don't have a fire department..... Or a building inspector....Or a Town for that matter. - I'm 13 miles from civilization on the side of a mountain and I fucking love it!

 

[50BMG DUDE]

How much foam under and around the slab?

2" Blue foam Under and around 24" down around perimeter. Slab heat works good, just can't keep the heat inside the building. I do have 2 big OH doors 14x14 and 12 x12, but they are high density foam filled steel on both sides 2" thick doors.