It can take from four to eight weeks to design a small addition or remodel; and three to four months or more to design a new home. It typically takes another one to two months for prospective contractors to assemble bids plus time for the owner to choose a contractor and sign an agreement.
According to the just-released U.S. Houzz Barometer Study, 2014 saw double-digit growth for residential construction and renovation, and 2015 is expected to be just as good, if not better. I know of residential builders in my area who are already booked through the end of this year and others who have projects scheduled well into 2015.
If you're planning to build this year, you should make sure to allow plenty of time to get the process going.