We bought a 165+ year old house.The basic frame is 8"&8" hardwood beams notched and pinned together.The foundation is sandstone,a thin layer of some kind of morter and a plate of these 8 by 8 beams. I had to replace some rotted sections.I did this by making a form and pouring 4 ins. concreat on the sandstone foundation.Than I put down a treated 4 by 6 plate.I noticed some of the other beams are getting soft spots at bottom of beam were it sits on moter/sandstone.Some of this can be scraped away to reveil good wood. I have also noticed by drilling holes that some beams are hard outside but are softer inside. I hope this is not termites.At anyrate I don't want to replace this wood if I don't have to. I thought about drilling alot of 1" holes[ about 6" deep ] in a pattern in the top of the beams between the wall studs and filling these with something like linseed oil[ and maybe some bug killer].After a few days it could soke in and I could refill them. This is an experiment for me so if anyone has a better idea I would love to hear from them. Also if there is something better than linseed oil for this[now that coal tar creasote is not available]I would like to know about it.