Try this one on:

--set up

declare @dateStart datetime

declare @daysToAdd int

declare @dateEnd datetime

declare @baseday datetime

select @datestart='9/1/2007',@daysToAdd=52

--start by making sure your start day IS a business day

Select @datestart=dateadd(dd,case when cast(cast(@datestart as datetime) as int)%7 >4 then

7-cast(cast(@datestart as datetime) as int)%7 else 0 end,@datestart)

select @datestart

--the magic

select @dateEnd=dateadd(dd,

case when cast(cast(dateadd(dd,@daystoAdd%5,@datestart) as datetime) as int)%7 >4 then

7-cast(cast(dateadd(dd,@daystoAdd%5,@datestart) as datetime) as int)%7 else 0 end,

dateadd(dd,@daystoAdd%5,dateadd(wk,@daysToAdd/5,@datestart)))

select @dateend