Insulating around attic trusses

[stockwell45]

Hello, been a long time reader but have finally gotten to the point where I am about to have my garage built (put down deposit today, looking like they will begin around the end of October). I am having a 30x64 post frame building installed. I am planning on it being climate controlled with radiant heating in the slab. I was back and forth on having attic trusses installed, and finally decided to go with them. Now I am trying to figure out if I want to insulate the attic section, or leave it as cold storage. I had planned on Rockwool in the walls and blown in insulation in the ceiling, but now am not sure what to do about the attic portion. I imagine I could frame walls and insulate the sides pretty easily, but what about along the top? I appreciate any/all advice!

 

[Firebrick43]

Attic loads usually do not work with a pole barn construction. If you get it engineered to transfer the load to the poles correctly and excavate and pour sufficient sized footers you will have been money ahead to frame a conventional platform or ballon frame construction.

 

[firebirdparts]

True. Superior building for sure.

Anyway, If you don’t want to spray foam, I would probably add blocking as needed in the attic to create enough space for appropriate thickness of fiberglass around the attic. I guess you could make the truss supplier do that for you.

 

[Dragfluid]

You said rock wool in the walls. Did you mean mineral wool by chance? They are not the same, and both are expensive compared to other ways. If you're using this for the fire barrier aspect, dense pack cellulose will do the same at less money. And dense pack has a higher R value per inch installed. Please look into it. If you like, click on the link that I still have down at the bottom. It's my build thread of my old shop. It shows what I did and why.

As far as "cold storage" in the attic, I've said this before. Things that you put up there will more than likely still be there ten years later without being touched.

 

[Dragfluid]

??

 

[stockwell45]

Attic loads usually do not work with a pole barn construction. If you get it engineered to transfer the load to the poles correctly and excavate and pour sufficient sized footers you will have been money ahead to frame a conventional platform or ballon frame construction.

I am working with a local builder who seems very reputable, I am not sure what all he adds for doing them, but the price seemed very fair to add the attic trusses instead of regular (although I did not get comparable quotes to go stick frame). I have also seen 2 other buildings the builder has done this in, one of which is my dad’s. Not saying you’re wrong, but comparing the cost to add the attic vs adding a shed or something else for the equivalent storage space, the attic is cheaper.

True. Superior building for sure.

Anyway, If you don’t want to spray foam, I would probably add blocking as needed in the attic to create enough space for appropriate thickness of fiberglass around the attic. I guess you could make the truss supplier do that for you.

I am considering spray foam for the roof. The issue is getting someone around me to actually give me a quote/say they will do the work. Left multiple messages with a few company’s and waiting to hear back.

You said rock wool in the walls. Did you mean mineral wool by chance? They are not the same, and both are expensive compared to other ways. If you're using this for the fire barrier aspect, dense pack cellulose will do the same at less money. And dense pack has a higher R value per inch installed. Please look into it. If you like, click on the link that I still have down at the bottom. It's my build thread of my old shop. It shows what I did and why.

As far as "cold storage" in the attic, I've said this before. Things that you put up there will more than likely still be there ten years later without being touched.

I appreciate the response. Looked through your build and was pretty helpful, at least in getting me started down a rabbit hole of researching dense packing. I think the biggest concern is knowing it will likely be a diy I am worried I wouldn’t do the install correctly to get the full R values, where Rockwool (while more expensive) seems a lot more user friendly for an install. I am hoping to find a way for the attic to not just be storage, but be heated/cooled with the rest of the building. This way I can put my home office/fly tying/reloading benches there and Have it separate from the gym/family area below

sorry for the delayed response, was out for work after posting. I very much appreciate all the help!

 

[mepstein]

I used rock wool in my workshop. I will never use fiberglass again. The price stings a bit but the material is superior in so many ways.

 

[stockwell45]

I used rock wool in my workshop. I will never use fiberglass again. The price stings a bit but the material is superior in so many ways.

Watched rr buildings YouTube videos on it and that’s what has me leaning that way for the walls. I Had intended to do rockwool in the walls and a full ceiling with blown in above, but now that I am adding the attic trusses I’m rethinking ceiling insulation to try to include the attic section as a heated and cooled area. I am between doing blown in on the part of the trusses with no attic, and then figuring a way to just get Rockwool around the attic portion, or leaving the trusses open and spray foam on the roof?

Appreciate the feedback on Rockwool!

 

[mike93lx]

You said rock wool in the walls. Did you mean mineral wool by chance? They are not the same

Rockwool is just a brand of mineral wool insulation

 

[Dragfluid]

Rockwool is just a brand of mineral wool insulation

I looked it up before I wrote that.

 

[billconner]

Attic trusses in a post frame building is interesting. I'm guessing your posts are 8' on center on load bearing walls? It would most likely require headers to carry the trusses, in the double or triple 2x12 range I'd guess. Around here, with snow loads of 60 psf, the a 30 or 40 psf live load over 50% of the area doesn't make much difference.

Can you say what the attic truss floor live load is?

My single experience with a post frame company was them stating emphatically the same space on ground floor was less cost than attic truss. I eventually stick framed it myself with attic for less than half the cost of a post frame "kit". No idea of cost of crew to have it erected.

 

[stockwell45]

Attic trusses in a post frame building is interesting. I'm guessing your posts are 8' on center on load bearing walls? It would most likely require headers to carry the trusses, in the double or triple 2x12 range I'd guess. Around here, with snow loads of 60 psf, the a 30 or 40 psf live load over 50% of the area doesn't make much difference.

Can you say what the attic truss floor live load is?

My single experience with a post frame company was them stating emphatically the same space on ground floor was less cost than attic truss. I eventually stick framed it myself with attic for less than half the cost of a post frame "kit". No idea of cost of crew to have it erected.

Posts will be 8’ on center. Floor load in the attic is 50psf.