when a piece of wood starts bearing weight it also becomes a little more dense due to compression.
if your gonna build an ohsht house might think about covering it in dirt to make it more like a small hill then plant edible plants on it. you not only get superior armor you also get superb insulation and a source of food.
just an idea
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
Depending on where you live, try picking a different type of wood (unless you really want pine). Cedar is a good choice. It a lot more rot resistant than pine, and is usually harder too. Where are you going to be building this thing that you have to worry about small arms fire?