J. Clarke wrote:
It's an old barn, (I mean _real_ old, older than the US). Pole and beam
construction with vertical plank sheathing. There's a gap between the
planks and most of them have knotholes. No historical district,
register of historical places, or other restrictions except the normal
building codes, under which the barn is grandfathered.

The desired result is to more or less maintain the appearance of the
barn inside and out but have it weather- and critter-tight. It's going
to be used for a garage, workshop, and storage, not living space.

Seems to me that the planks have to come off, sheathing has to go up,
and then the planks have to go back, furred out so that rain coming
through those gaps and knotholes doesn't get trapped. Anyone have
another idea on this?
....


Agree w/ other posters first...

How big is it?

Are you aware of the National Barn Project at Smithsonian?

There are certain (fairly small but might as well know about them) tax
breaks for some types of restoration.

Rather than what you're proposing, my first thought for actually
building a tight facility given the starting point would be to
essentially build a building inside the current frame/siding and simply
stabilize the existing work. Trying to take an old barn of that age and
actually make it into a building such as you describe is, imo, a lost
cause unless simply want to start w/ a new structure and then use the
exterior material as siding.

There's unlikely to be adequate foundation, the aforementioned issues w/
poles, etc., etc., etc., ...

Pictures would be nice...

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