Vapor barrier in ceiling

[larrybr45]

In my manuf. home looking to install 3/8 pine planks over the existing drywall ceiling. Since my walls eventually will have tyvek on outside and then a vapor barrier under drywall, should I put in a vapor barrier on the ceiling drywall PRIOR to installing the pine planks on the ceiling.

I want to avoid the pine or drywall holding a lot of moisture.

Finally, I assume I dont need to tear out the existing drywall ceiling prior to installing pine planks (due to weight or other issues)?

[mannymanbo2]

The ceiling gypsum must be left intact for the structural integrity of the home.
There is already a vapor barrier on the ceiling. If you want to add to that, I suggest vapor barrier paint that is readily available.
Now, if you put wood planks on the ceiling, you will violate the HUD code, Section 3280.203 that limits flame spread on the ceiling to 75 or less.
Wood planking is generally around 200!
Your insurance company might have a problem with that as well.

[larrybr45]

Thanks for the info.

If I put the board up, then no added vapor barrier required if I understand you?

Homeowners put up wood ceilings all the time, how would violating HUD hurt me when I go to sell (this property has permanent foundation, no title is considered real estate) and is on a lake?

just trying to understand likely risks of violating HUD.

thanks

[rmurray]

If it is a manufactured home built to the HUD code and you sell in the future it will have to pass an inspection by a FHA inspector who might write it up as a "modified" manufactured home that no longer meets the code...That could stop your buyer mortgage and cost you the sale and time in the sale...FHA is by far the most common mortgage for homes today.(the future who knows?)....You could be eliminating a large part of your resale prospects...HUD will do nothing directly to you...

[trmimo]

Also, you will be adding significant dead load to the roof system wich means the live load (snow load) decreases the same amount. If you live in area without snow you probably have a 20# roof load and the weight of the pine would leave you with little or no roof load capacity at all.

[larrybr45]

This is great info. If I decide to do due to aesthetics, should I put vapor barrier over the drywall with the 2006 HUD changes requiring a retarder not greater than 1 (knowing it was built in 1988 and I dont know what is under the sheetrock ceiling)?


In terms of load, that concerns me. How much risk if I stick with installing 3/8" pine, would I face. We do have snow in Northwest ohio and I dont want to jeopordize the structure. Maybe I can find 1/4" or less pine. I just really like the look.

[trmimo]

I wouldn't put a vapor barrier between the drywall and wood. You don't want to trap moisture against the face of the drywall, you will encourage moisture build up and mold growth on the paper face of the drywall.
The weight is easy to figure. The package of wood from the home center should say the weight of the material and how many square feet it covers. Divide the package weight by the number of square feet and you will know how many pounds per square foot you are subtracting from your roof load. You can find the roof load capacity for your home on the data plate. If it is 20#, you don't want to add anything to your ceiling. You are only about a 100 miles from the northern limit of the 20# zone.