?'s on insulating a shop

[ladrhog]

Hi, and thanks for taking the time to read this and hopefully respond.

I live in eastern washington. I had a 30 x 40 x 14 pole barn built with commercial girting. The builder put tyvex house wrap on the outside of the structure before putting on the metal. There is also osb and felt on the roof under the metal. The floor was poured on 10-29 4 inch slab on 4 inches of road base 5/8 heavy minus on decomposed granite fill and virgin soil.

For heat I have a 75,000 big maxx heater installed. Problem is there is no insulation yet. If I turn the heater on it seems to instantly get wet inside the structure. I am doing electrical now and getting ready to insulate. I am thinking I am going to use fiberglass bat insulation but if it is going to get moisture in it I don't think that would be a good choice. I have a thermostat that will go down to 35 degrees and was hoping to keep the structure from freezing but will I be doing more harm by getting everything wet. I will be trying to get it insulated this winter. I will try to include some pics

I would like to know how to insulate this? Will i need a vapor barrier on the inside also?

 

[Kevin54]

The reason you're getting condensation is due to the fact that you have no insulation. When you have the warm air meeting the cold panels, your condensation starts. Basically the same as if you pull a car that has been setting out in the winter into a warm garage. It will develop condensation all over it.

You could use a vapor barrier inside. I truly feel though that once you have it insulated, you won't have any problems with moisture.

 

[Steevo]

Like Kevin said, if you can get insulation in between the warm interior air and the cold exterior surface, no condensation should occur. If you use unfaced batts, be vigilant when installing insulation to get it tightly fitted along the edges, so you don't have air flow gaps, and then cover the interior of the walls with 4 mil plastic before sheathing them with sheet rock or OSB or whatever you choose.
I assume you plan to use kraft-faced bats/rolls to do the roof? With the way it is constructed and the roof framing between trusses, I don't see how else you can insulate up there.

 

[ladrhog]

I plan on sheeting the underside of the trusses with osb and then blowing in insulation.

 

[Falcon67]

With Kevin and Steevo on this. I never thought about it until the walls were up, but Hardi Panel acts a bit like steel and on sharp weather changes, it can sweat some on the inside. I used kraft face with OSB on the inside and no vapor barrier in or out. I recently had a wall open for some wiring and there was no sign of condensation or mold on the Hardi side of the insulation. I still see condensate on the outside once in a great while, but it has to be from a quick change after warm days to cold and damp. We get cold fronts but very few have any moisture with them.

We have a sharp change coming Sunday night - might have to pull a panel Monday night just to see whats going on in the wall.

 

[ejkuhl]

I used kraft face with OSB on the inside and no vapor barrier in or out.

The kraft faced should be a vapor barrier. Usally the paper is coated on the insulation side.

 

[Steevo]

I plan on sheeting the underside of the trusses with osb and then blowing in insulation.

In that case, I think I'd staple up heavy, clear vapor barrier (6-mil?) on the undersides of the trusses, then have the insulation blown into those areas. That way you can see the fill coverage and take care of any gaps/voids. Then when the insulation is all in there, put up the OSB. If you sheet with OSB and then blow the cavities through holes in the OSB, you will never know how even the fill is or whether there are voids where you are losing heat, plus you have all those OSB holes to fix/cover.

 

[ladrhog]

I am going to have an access for storage so I can blow it in that access