I am building a garage and installing log siding on it to match my log home. I have been told to stain the back of the siding prior to installing. I am guessing this is to protect the back side of the wood from moisture. Is this necessary? I plan on installing wood lath to allow a 1/4" gap between the siding and the house wrap over that is installed over the sheathing.
My house is log construction but on the upper portions of the gable ends near the peak of the roof it has log siding. I have replaced a few pieces due to woodpecker/bee damage and they were not stained on the back side, and they were installed right up against the house wrap with no gap. I have not had any issues with the siding on my house and it has been up for over 20 years.
I am just trying to save money and time if possible.
There are arguments both ways on this issue. Some say that staining the backside will protect the wood against rot if moisture gets behind the siding at all. Others say you'll trap too much moisture by "encapsulating" the wood on all sides, which makes it harder for any moisture that does get in to escape. (Gotta love conflicting messages!) Given your experience, I'd say your gut instinct on this is pretty good. No need to stain the back side unless that siding isn't going to be protected by eaves/overhangs. I would instead recommend you apply a borate-based wood preservative to all sides before staining. IF moisture does make its way to the backside of the siding, the borate will be activated and help prevent any rot. It's much cheaper than stain and certainly less time consuming. (Apply with a garden pump sprayer and allow to dry. Pretty simple.) Once borate is applied, then you can stain just the front side of the siding.
Hope that helps. If you want more info on the available borate-based wood preservatives out there, let me know. I'm happy to be a resource.
Have a great day!
--- Charis w/ Sashco - www.sashco.com - firstname.lastname@example.org