Insulating A Small Workshop

buddyb

My son has a small 12x24 building with metal siding.I plan to help him insulate it with fiberglass batts and put OSB over it.If we use unfaced batts,should we put up plastic sheeting over the batts before putting up the OSB?

woodshed87

Yes that Is What we Call A Moisture Barrier[^]

1911a1-fan

they need a vapor barrier

spasmcreek

vapor barrier, insulation, sound deadening, strengthens structure....all in one spray foam

pip5255

alot depends on location and building codes.

gunnut505

If possible, wrap the whole inside with several layers of thick plastic sheeting. Comes on rolls at harbor freight. Anyway, it "seals" the outside of your batts from moisture (rain, snow, hail), and adding another layer covering the inside surface before adding the OSB just makes sense.
Sure, it's over engineered, but I've got all day.....

Alpine

Think about 5/8 type X drywall for the inside. It has some sear strength, and gives you a fire barrier also.

skicat

quote:Originally posted by gunnut505
If possible, wrap the whole inside with several layers of thick plastic sheeting. Comes on rolls at harbor freight. Anyway, it "seals" the outside of your batts from moisture (rain, snow, hail), and adding another layer covering the inside surface before adding the OSB just makes sense.
Sure, it's over engineered, but I've got all day.....


You don't want to have 2 vapor barriers. It traps moisture in between and encourages mold.

84Bravo1

Why would you want to insult a small workshop??

LesWVa

quote:Originally posted by buddyb
My son has a small 12x24 building with metal siding.I plan to help him insulate it with fiberglass batts and put OSB over it.If we use unfaced batts,should we put up plastic sheeting over the batts before putting up the OSB?


No, not over.
The Vapor Barrier goes to the outside between the metal and insulation. Not between the insulation and OSB.

Not knowing what type of construction method was used to build the shop. Hard to give any recommendations on insulating. 75% of metal buildings here use pole barn method. 4x4 or 6x6 post and 2x? stingers to attach the metal siding to. This method only gives you about 1 1/2" of space for insulation between the metal and OSB (or whatever you use) unless you go in and install studs.

1 1/2" of spray foam insulation would not be worth the cost. For You will have about a 6 or less R value.

buddyb

Framed out with 2x4 24 on center.

LesWVa

quote:Originally posted by buddyb
Framed out with 2x4 24 on center.


Faced Polystyrene Foam Board Insulation (1/4" x 4' x 50' = $50 Lowes, Easy to cut to size) glued (Power Grab) to metal, Un-faced insulation then OSB.

Ricci Wright

Here is a series of videos that may help.
https://www.youtube.com/watch?v=jWjH0XFhwdo

asop

So is it a metal building or a 2X4 framed structure? Approach for attachment will very. But in either case a batt insulation with a vinyl reinforced facing (vapor barrier) install with the vapor barrier facing the interior. If you can find insulation with 6" or so of vinyl projecting out past the fiberglass you "roll" the ends together of each adjacent piece and staple. Gives you a good end product. This is how metal building insulation is installed.

fideau

Vapor barrier goes toward the INSIDE (heated area) of a building.

+1 on the spray foam.

allen griggs

"No, not over.
The Vapor Barrier goes to the outside between the metal and insulation. Not between the insulation and OSB."

Nein!! Verboten!!!

The vapor barrier goes on the inside.
Why not just get faced fiberglass insulation it has a vapor barrier built into it. Put the paper/vapor barrier side towards the heated part of the structure, the inside.