Large buildings, where I like to create an attractive interior living space, the horizontal slating goes to the outside. On smaller utilitarian housing, like stilted swamp portal/rest/repair shelters, slats are inside. 80% of my buildings these days are repair & restoration of abandoned buildings, I go with what is present upon discovery. I will leave as much of the existing structure as I can, and either add to the height of the walls or extend the walls outwards, or both, increasing the overall interior square footage. Oft times on my larger dwellings, I will slap darkwood horizontal beams on the support beams. I have even double walled a few homes, so no support planking is visible inside or out. I also have a few houses built with the lower 1/3 - 1/2 of stone, and the upper portion corewood poles.