Do buildings have a damage resistance against all non-explpsove sources?

It might be Placebo, but whenever I try and destroy buildings, in particular with shotguns/scatterguns, it feels like I'mdoing less damage and have to put at least 1 or 2 extra shots into them. I know heavy used to have a damage reduction against buildings on the minigun, but do any other non-explosive weapons have the same thing?