i specialize in interior trim for custom new homes and remodels.typcially designing the trim package.. most often you want the baseboard 2" taller than the casing is wide. and mike is right about having the base thinner than the casing though..
as for having to rip the casin this is very common when the framer doesnt allow for the casing width... you can either go with a narrower casing or just go with a 3" or 3 1/2" casing and rip it down as needed. i have to do this all the time on the inside of closets
as for having to rip the casin this is very common when the framer doesnt allow for the casing width... you can either go with a narrower casing or just go with a 3" or 3 1/2" casing and rip it down as needed. i have to do this all the time on the inside of closets