Because of cohesion and transpiration, water is able to move against the flow of gravity in plants. The attraction of water to other water molecules, or cohesion, allows water to pull other water molecules up through the xylem.
Room addition cost about $210 per sq.foot and if there is a bathroom in addition you should add $5,000 in average and if there is a kitchen in addition you should add $10,000 in average to total price of $210 per sq.foot x sq. footage.
1. Edit Answer (for another 5 minutes). Nationwide average code to modify a house to add a bathroom (without pushing out walls or adding foundation) is about $37,000. Some are done on the cheap for about $15,000 for a half-bath, and fancy ones of course for 5/4 bath or fancier can run $50-80,000. Obviously, if you can back it up to another bath for easy in-wall pipe access that will help keep your costs down.