We just finished building on to an existing bedroom & bathroom and are ready to paint. We hired a professional painter (30+ yrs experience) who is planning to cover the new drywall with one coat of Sh. Williams eggshell paint (off white). We thought he should prime first but he says it's not necessary. We're a little concerned - can anyone out there offer an opinion? Also, is eggshell ok to use in a bath? Thanks.