I just bought a new home and I would like to board and batten a very ugly shed that is on the property. It's a large shed with a concrete floor that I plan to use as a work shop. It will have a wood stove in it for heat. Should I wrap the outside of the building before installing the B&B? There is currently that old ugly gray shingle stuff on it. If I wrap the outside do I also vapor barrier the inside?
Yes I would install a new MOISTURE BARRIER before installing the board and batt. (We Install moisture barriers because we know the siding will leak due to rain storms, wind, etc.)
If you live in a cold climate in winters, I’d use a VAPOR BARRIER on the batt insulation but don’t install plastic sheeting on the walls.
We’ve learned that vapor will past the plastic sheeting (around outlets, joints at floor and ceiling, etc.) and turn to moisture. However, it will not be able to “escape” out of the stud space and go back into the house when temperatures reverse. (I’d just provide a coat of paint with a good perm rating. )
I think on an old shed with a wood stove I'd worry mostly about not getting any water trapped and rotting things. I'd probably go with a double layer of asphalt / tar paper on top of the old sheathing, I just trust it over the plastic or Tyvek wraps.
I'd consider screwing the board and batten right to the sheathing, but probably prefer to attach it to horizontal furring strips. With furring strips you could use foam board between the furring strips for insulation if you need it, but even without the foam, the dead space should provide some additional insulation and a rain screen.
Tyvek is NOT a vapor barrier, it is meant to resist water penetration but still breath. It is designed prevent most outside rain and such to sheet off, but to still allow any water vapor trapped behind it to pass into the outside air so it doesn't condense behind it (i.e. inside your walls).
A vapor barrier (e.g. plastic sheeting) should always be placed on the warm side of the insulation. In your case over the rock wool insulation. It is meant to prevent the water vapor in the inside of the warm building from penetrating through to the insulation.
R-value, condensing, vapor trapping, drying time, mold, health problems.
To get accurate information, this web site may help:
By inputting all existing and planned layers, possible problems will be shown in a second.
Experimenting/researching is easy by switching on/off of layers.
R-value can be shown by clicking on the spanner/tool icon next to the U-value.
It s free for private use.
Disclaimer: I do not have any association with that web site, I do not benefit/profit in any way from my recommendation of that site. It is just by far the most professional and sophisticated site to calculate and visualize the relevant insulation parameters that I have found up to now.