30x48 insulation for humidity control.

[47WDXPW]

My goal is to insulate to control humidity at least that's the goal. The girts are 6'' deep everywhere but the roof has an insulation blanket that was installed when the building was erected maybe 2''. Would 6'' of fiberglass with sheetrock covering do the job Im not sure if there is a better way to go. I have electric and the possibility of running natural gas the house has it. The floor only has plastic as a vapor barrier. How would a vapor barrier work for the walls and would the building need to be air tight ?

 

[47WDXPW]

Is the goal of a job like this to seal the building of air flow ?

 

[LS6 Tommy]

Insulation won't reduce relative humidity. It might keep the underside of the metal from sweating when it's cold out, but that's about it.

Tommy

 

[Showkey]

Insulation and conditioning the air will control the humidity. Mother Nature is control if you do not seal the building and condition the air inside the building.

Conditioning the air is controlling the air exchanges and heating and or cooling. It does not mean you have to have AC. In the summer a well sealed building like garage or shop might need a dehumidifier to keep the humidity at a desired level.

Measuring the temperature and humidity is important ...........when inside a building reaches a prolonged 70 % humidity bad things start happening.

 

[theoldwizard1]

If you have large doors you will never be able to control humidity without A/C !

As for insulation, start by having 2" of spray foam applied. It will seal all small cracks and holes and help control the humidity. After the spray foam, install your favorite insulation, the more the better.

 

[47WDXPW]

Thanks for the responces, I may be able to get batts insulation at a below market price if using that will a vapor barrier be needed ?

 

[mrpizza]

I am building a pole barn house. It is getting 5" open cell 3/4lb spray foam in the entire walls and roof and everywhere. It will be like living in a yeti cooler.

Price will be cheaper than doing a seal coat of spray foam followed by cellulose and such, for a MUCH better R- value and very very minimal air leakage.

I vote foam. Less labor than batts brings the price in line with other forms of insulation.

 

[47WDXPW]

I see foam keeps coming up is there any truth to foam and rust of the metal surface its applied to ?