For new builds or repair. The horizon footer obviously should have a vapor barrier like flashing or whatever local code recommends in contact with the concrete and board it's self pressure treated. The for the wall studs I'm thinking dip the bottom 2 feet in something like: Thompson's water seal. I have several gallons, would have to buy more eventually and I don't think it's rated to repeal bugs. White wash, which I think is just quick lime. Pretty sure they won't eat that or crawl on it for very long. The cheapest, fastest and probably the worse would be used diesel engine oil. Bugs will definitely avoid, it stinks, could stain through drywall, kinda combustible. The wall studs could just all be pressure treated but that doubles the price. I've been using pressure treated around doors and windows for a long time, just have to try and pick out ones that look like they'll dry straight, allow them to fully dry and only use ones that dry straight enough.
I've used the green net dip in a potato sprayer but it does have a smell that hangs around a good bit. Bunch of products out there, even hot sauce.
Just go with steel studs. Remember those little bastards will build tunnels straight up an eight foot tall concrete block wall to get to tasty timbers
Since the guberment mandated a change in the way pressure treated lumber is made it is pure crap. Go with steel studs
I used that back in like 2006 hadn't seen it in almost as long, figured they didn't make it any more. Yeah that would be my top pic if it's still sold.
I've heard they usually don't build castings up more than 2 or 3 feet unless they already know there's food, say they've already established a colony in structure in question. I recall the directions on that green stuff gator is talking about saying something to the effect of "spray it 2 feet above grade". I sprayed it all over the underside of my pier and beam house in Virginia. Every square fucking centimeter until it dripped, sil, footer, kick plate, floor boards and the subfloor, from underneath.
Thank goodness here in North Idaho we don't have termites. As far as I know, we don't have rats either, certainly got mice though.
I wonder if something like Clorox might work? As a builder myself,, I've thought about this a few times over the years . It's an added expense from labor and materials,, but could be an actual benefit. But when you get the ground treatment from done before any concrete goes done ,, that'll help a lot ,, and just getting a Pest control company to come once a year for treatment is a good idea ,, cost was about 125 bucks a year , for a yearly treatment. You could probably just mix up your own clorox and dawn detergent and spray around your home a few times a year,, having to go under your house would be a pain,, but ,, you could put a small hose around the inside foundation and pump it threw like a soaker hose . But I could be overthinking things.