On Sat, 04 Jul 2015 10:16:33 -0400, Larry Kraus
wrote:

On 7/4/2015 8:59 AM, Bob Engelhardt wrote:
On 7/4/2015 2:13 AM, pyotr filipivich wrote:
...
Outside is primed a nice beige color, but the inside is not. There
being a lot of OSB, the recommendation is to paint/ seal it before the
rains resume. ...

I've never heard of the inside being painted for rain protection. Is
there something about your weather that requires that? Or is there
something about the shed construction that allows rain in?

If you're worried about protecting the inside surface from rain, I would
also be worried about the (fiberglass, I assume) insulation getting wet.

Also, .... no, wait - I just don't get this painting the inside. Please
explain.

Bob

The concern is that paint adhesion on the outside can be adversely
affected by moisture migrating through from the inside. This is a
definite problem with masonry, solid wood and plywood. I'm not sure
about OSB as it may contain enough glue to block moisture. Better to
seal it while the opportunity is available than to be frequently
scraping/repainting the outside.

Standard "exterior" grade OSB will not likely transfer any moisture.
the layup glue prevents this.

Gunner