Shiplap siding should be installed to shed water with the lap. Most also use an underlaying barrier, also lapped to shed water.

So it's siding directly on the studs without any sheathing? What kind of climate are you in?

Yes, no sheathing. We are in north central texas, east of dallas. I have not witnessed moisture or water in there but there’s no way that that isn’t or won’t happen.

Seems as though previous owners caulked along inside seams for the most part, old and dried though now, maybe replace and continue also i might go ‘vertically’ where studs are too? Hate to go to the trouble of insulation and sheetrock interior for it to get wet or moisture behind the walls from outside? Thanks for coming on...

I would want the siding to be removed, and sheathing installed, and then new lap siding, so you know it is going to be dry. It isnt all that important right now with a garage, but, it will be extremely important when that becomes a living space, and everything is all sealed up.

Check out this article at greenbuildingadvisor.com : https://www.greenbuildingadvisor.com/article/insulating-walls-in-an-old-house-with-no-sheathing You may need to get a free temporary membership.

That’s what i was afraid of, lol, thank you and so right you are! I will look at the website may not go back with same siding, something better, may could repurpose all the shiplap to the inside when time comes.