Insulting a barn roof

[Steve Rozmiarek]

It looks like there is a chance I could be moving my woodshop again. This time to a barn, which sounds really appealing to me. It's a standard layout, divided into three sections, with the center having a haymow. Good ceiling height, good roof, and not a terrible amount of structural issues. I'm developing a plan should this materialize to use the center section and haymow, and one of the sides for the shop. It would actually be a little smaller than my current shop, which I love, but this one would be in better location.

My question for you construction guys, how would you insulate the roof to best keep the ceiling height? Steel roof over osb over original board sheeting. I'm tempted to just consider fiberglass batts in the bays because I think the roof will breath to some extent over it because of the gaps in the original sheeting. Thoughts?

For the record, I'll add that I didn't insult the barn roof, that I know of. Leaving the title of the thread alone though because it's amusing.

[Kent A Bathurst]

Steve -

I am waiting anxiously to find out what you did to insult your barn roof?

Not only what and how, but why?

[Mel Fulks]

The last "insult" was to an attic ,and I was the policeman on that one. Now it's risen to rooves. Gentlemen, civility please!

[Steve Rozmiarek]

LMAO!!!! This is why you should never post a new thread from your cell phone and not proof read...

Maybe it was a freudian slip, maybe I was feeling like the barn would be insulted by the very thought of being repurposed as something besides the noble calling of domestic livestock domicile? Maybe the barn has feelings too? I only hope it's not a needy personality... Oh brother, this could get weird.

[Allan Speers]

I only wish I had an unused barn to insult.

[Allan Speers]

Once your barn gets over it, I suggest the exposed batting. - But use mineral wool, not fiberglass, as the wool doesn't put dangerous flecks into the air and doesn't make you itch when you touch it. (It costs a little less, too)

The reason I like the exposed bats is because then they will also act as sound absorption, which isn't a bad idea in a woodshop. If you have a lot of high-pitched machines, stick with 3 lbs / sq ft mineral wool. However, if most of the noise is mid & lower frequencies (like with a big DC) then opt for some denser wool. Maybe 5 lbs.

if you do use rigid fiberglass, make sure you cover it with some kind of cloth or burlap.

[Steve Rozmiarek]

And I feel so bad for doing such a thing Allan! ;)

[John K Jordan]

My architect friends recommend spray-on foam insulation. Another friend who is a builder used it in his own buildings.

[Roger Pozzi]

My architect friends recommend spray-on foam insulation. Another friend who is a builder used it in his own buildings.

Plus 1 !!!! I had a warehouse sprayed quite a few years ago and it is fantastic! You don't need to provide air flow between the roofing and insulation and it's totally air/water tight. But,,,,also very expensive, at least in my area. :(

[Steve Rozmiarek]

Roger and John, I have a built in knee jerk type of response to sprayfoam. Probably because it's so ridiculously expensive in this area that I've given up on it. Also, I like the idea of being able to reverse whatever I do to buildings, so spray foam is down the list of options a bit.

The barn has 2x8 (full dimension) rafters on 24" centers, so something with more R per inch wouldn't be bad. Haven't checked yet, but I suspect that mineral wool beats fibreglass?

[Brian Tymchak]

...You're nothing but a saggy, mold-ridden, beetle-infested pile of half-rotten No. 2 shorts!!!

:D

[Steve Rozmiarek]

...You're nothing but a saggy, mold-ridden, beetle-infested pile of half-rotten No. 2 shorts!!!

:D

Now that ought to insult any building up to and including outhouses! Lol!

[Walter Mooney]

It looks like there is a chance I could be moving my woodshop again. This time to a barn, which sounds really appealing to me. It's a standard layout, divided into three sections, with the center having a haymow. Good ceiling height, good roof, and not a terrible amount of structural issues. I'm developing a plan should this materialize to use the center section and haymow, and one of the sides for the shop. It would actually be a little smaller than my current shop, which I love, but this one would be in better location.

My question for you construction guys, how would you insulate the roof to best keep the ceiling height? Steel roof over osb over original board sheeting. I'm tempted to just consider fiberglass batts in the bays because I think the roof will breath to some extent over it because of the gaps in the original sheeting. Thoughts?

For the record, I'll add that I didn't insult the barn roof, that I know of. Leaving the title of the thread alone though because it's amusing.

The title was the only reason I clicked on this thread.:) I couldn't wait to see some of the replies, because i know there are many quick-witted Creekers out there with a retort just waiting to be typed!

But seriously, with 24" o.c. rafters, whether you use either fiberglass or mineral wool, i would staple chicken wire (poultry netting) to the inderside of the rafters after you've installed the insulation, because batts that wide will tend to sag quickly. I would imagine that fiberglass batts are probably more common and more easily obtained than mineral wool, thus possibly cheaper. If you use the batts with either a paper or foil face on them, install with the paper or foil facing the heated/cooled space. If you're installing it yourself, get a pair of tube socks, slit the toe open and pull one onto each arm to act as a sleeve to keep the fiberglass off your skin. Dispose of the 'sleeves' when you're finished. Get a good N95 dust mask.

[Kent A Bathurst]

Now that ought to insult any building up to and including outhouses! Lol!

I am working up some "yo mama" slams for the next time I see a barn when I take a drive in the country.

One of them - still needs a bit of refining - is............ "Yo mama is an outhouse"

Also...

"Yo mama's make-up was applied by a flock of pigeons"

"Yo mama's so wore out she don't even cast a shadow"

Trying to think up a hook that connects a barn roof to a mobile home roof in a tornado......not quite connecting yet............

[James Conrad]

If you decide on a batt insulation, cover it with a vapor retarder. Otherwise, the moist warm air will travel through the insulation and condense on the other side. Without seeing the structure it's hard to be super specific. Batt insulation does not stop the passage of air alone. Cover it with rigid xps or other vapor retarder and tape the seams, it's less insulting for the building too.:)

[Brian Tymchak]

Yo Kent,,, is that the new you in your avatar?? The '70s called, they want their image back... ;)

[Kent A Bathurst]

Yo Kent,,, is that the new you in your avatar?? The '70s called, they want their image back... ;)

You are pretty much on target. Back in the 70s - my hair was longer than this.

7 years ago or so, I ended up on the beach. Stopped spending money on haircuts. Then, after 4 years - this is my photo.

We were weeks away from a trip to Patagonia, Cape Horn, and Easter Island. I decided I wasn't gonna drag that freakin' ponytail to the - literal - ends of the earth. Photo taken on my way to the barber.

Hair and shades hiding the face - this was as close to a photo of me as I was willing to put in front of you scoundrels..............

Oh - the big difference between this photo and the 70s - I am leaning on the Beemer in my driveway..........

Roy Bland, In Tinker Tailor Soldier Spy: "As a good socialist, I'm going where the money is; as a good capitalist, I'm sticking with the revolution............You scratch my conscience, I'll drive your Jag, right?"

Peace, dude.............

[Lon Crosby]

The best if you are thinking about AC is to install an “abovesheathing ventilated metal roof” and foam the bays. At 24” OC, you may be ableto save some $ by using solid rigid foam board, friction fit with one layerinstalled with contractor foam (in the large cans) to provide an air-tightseal. Conceptually, 2” of foam (either sprayed or sealed solid) plus fiberglassinsulation to fill the rest of the bay is almost as good. The downside is that 24” wide bats needadditional support. The ventilated roof will save ~15% on air conditioning operatingcost.

[Allan Speers]

My architect friends recommend spray-on foam insulation.


I don't.

In keeping with the "why not improve your acoustic at the same time?" idea:

Every spray-foam I've ever seen is closed cell. You need open cell foam, or fiberglass, or mineral wool, to best absorb higher frequency sabines. (sound energy) Additionally, spray foam tend to be pretty light, probably (I am guessing) significantly less than 3 lbs / square foot, so it won't have much effect on lower-mid frequencies at all.

[Allan Speers]

I am working up some "yo mama" slams for the next time I see a barn when I take a drive in the country.

One of them - still needs a bit of refining - is............ "Yo mama is an outhouse"

Also...

"Yo mama's make-up was applied by a flock of pigeons"

"Yo mama's so wore out she don't even cast a shadow"

Trying to think up a hook that connects a barn roof to a mobile home roof in a tornado......not quite connecting yet............



OMG, that's funny.

- But my workspace is so small and so ratty, it would consider any of those to be a compliment. :(

[Jim Andrew]

Questions, is the structure of the barn good? Are you planning to stay in the barn for a long time? I have a barn on my farm, but the foundation is not good, and it would take a lot to make it into much of a building. Is the roof pitch pretty high? My thinking is a 2x8 is probably not thick enough to insulate properly if you want to ventilate the top. If it were mine, I would probably try to fasten 2x4's under the 2x8's to give you adequate space for the insulation as well as vent it. And if you had soffit vents and collar ties to make a way to vent the upper part of the roof, should work as long as you leave a space on the outside for the air to flow.

[Steve Rozmiarek]

I never thought insulting a barn could be so funny, this is fun! Kent, I really want to hear that yo mamma trailer house one when you get it worked up!

This is a possible long term building, I won't work on it unless it is. Not going to put the effort into a building that isn't long term again. The last one I did, I put 2x8's under the 2x4 rafters, foam board insulation spaced down 2" and soffit and ridge vents to provide the ventilation for the roof. It was a stupid amount of work but the intent was to have ac and heat. That building was destined to be an uber shop, perfect in every way. I'm over that phase, what I want now is a building that I can keep above freezing always, and slow the heat/cool cycles to prevent rust.

To that end, the side part of this building has a cement floor, the center is dirt. Foundation is good except some on the east side where neglect let livestock uproot it and it went to heck. Needs repaired there, but that is pretty easy as it's just a side wall, not the corners. My thoughts were to fix that, pour a pad in the center section, and skim coat the rough existing concrete. Might as well take that opportunity to put some hose in the concrete and take care of the heating via floor heat. For cooling, I was thinking if I could insulate the ceiling to R30 or so, it would take the bulk of the heat out of the space. Strategically placed high and low windows are already there, so just using them to let the hot air out the top of the building and cool in the bottom. Lots of trees around, and the location will be a little cooler anyhow.

What I don't want is to spend big bucks and the next few years working on the shop rather than in it. Fun to ponder at least.

[Steve Rozmiarek]

Questions, is the structure of the barn good? Are you planning to stay in the barn for a long time? I have a barn on my farm, but the foundation is not good, and it would take a lot to make it into much of a building. Is the roof pitch pretty high? My thinking is a 2x8 is probably not thick enough to insulate properly if you want to ventilate the top. If it were mine, I would probably try to fasten 2x4's under the 2x8's to give you adequate space for the insulation as well as vent it. And if you had soffit vents and collar ties to make a way to vent the upper part of the roof, should work as long as you leave a space on the outside for the air to flow.

I forgot to mention the roof pitch Jim. I didn't measure it, so just guessing 4 or 5/12. Snow really comes off it fast, it's steep enough that shingling would require careful footing.

[Floyd Cox]

spray-on foam insulation is the way to go.

[julian abram]

I forgot to mention the roof pitch Jim. I didn't measure it, so just guessing 4 or 5/12. Snow really comes off it fast, it's steep enough that shingling would require careful footing.

Your roof pitch is steeper than 4 or 5/12. You can easily shingle up to a 6/12 without walk boards.