I live in central Texas and my house faces SW. I am supposed to have R-19 in my walls and R-30 loose cellulose in my attic but doubt that to be true because it gets way to hot in here in the summer (soffit and passive roof venting in attic). I am pondering removing my Hardi-lap siding, removing whatever insulation is on the SW side of my house, adding spray foam then a radiant heat barrier before reinstalling the siding. Will the spray foam hurt the drywall? I've pondered adding eave vents and replacing one of the passive vents with a solar powered fan, plus adding more cellulose and/or spray foam under the roof decking with a radiant barrier on top of that. Is this overkill? Would you recommend another way to insulate and keep my "energy efficient" three year old house cool?