where to get plans if modify floorplan

[mcompton1973]

I originally posted in general forum, this might be the better place.

OK, so a few things.
I am thinking of doing the 20x30 1.5 story but expanding it to 36-40 feet long.
I would do the pier foundation as I have a little bit of a slope on the land, and enough trees to make doing it truely level an expensive project.
I have not purchased, but I know about the software and site to modify the floorplans and things of that nature.
what I DONT seem to understand is how then do I get new plans based off of the modified floorplan?  In otherwords the plan is for 36'.  If I go 40' and put in a bathroom upstairs, where do I get plans to reflect that.  I plan to do a lot of work myself, but I work in roofing and have access to a frame crew for dirt cheep and will probably sub that out etc.  Early on we will be living in a shell of a house, and finish over the next few years until we have what we really want long term.

Here are my overall thoughts, this is for wife, me and 11yr old daughter....and too many dogs.
Wife wants a master bath that is not shared to guest/daughter.  So by expanding flooplan I can put a half bath for guests on main floor, and add a bath in the upstairs for my daughter.   That is a lot of bathroom relative to the size of the home, but it will make my wife happy in the long term, so not that big of a deal.  I plan to heat the home with wood stove suplemented with space heaters in bedrooms overnight if needed.  window air only, or possibly mini split units eventually.

Any info and thoughts would be apreciated.

We live in central OK, have no codes and winters are "generally" pretty mild.

[John Raabe]

You will likely get the best house by working with a local home designer to work up your building plans. For instance for what you want to have in the house you should have a full size stair and perhaps a 24' width.

I would suggest playing around with Sketchup to get the size and relationships of the spaces the way you like it and then find someone to work up the details.

I don't think one of my plans comes close enough.