Another item which is often missing or lacking in a set of house plans is comprehensive and accurate dimensions. We have always strived to provide more than the minimum amount of house dimensions so that it is easy for the owner and builder to layout a home on its building site. We will even calculate point to point dimensions (using trigonometry) for homes which have lots of odd angles to them (as opposed to a simple rectangle layout). Not all architects or designers will go this "extra mile," so it pays to check these things out beforehand.
The property owner can seek a variance to exceed the "building envelope," the allowable area that a home can occupy on a lot. However, the process is often lengthy and there's no guarantee that permission will be granted. Local zoning boards and community organizations often require a house be set back a certain distance from the street. Before purchasing a corner lot, find out if front-yard setback regulations apply to the lot's front and side-street boundaries. This could substantially reduce the area available for a home's footprint. Easements as well as natural features, like rock outcroppings and mature trees, may also influence where the house can be located.
Having been in the business for more than 30 years, we have seen a large number of house plans which looked good at first glance. However, upon closer examination, many of these plans were found to be lacking large amounts of needed information. If a house plan is not easy to navigate or is not thoroughly detailed, then the builder is left to guess at the designer's intentions. This often means that he will "pad" his bid to make sure that he covers any unknown construction costs that may arise.
Small house plans are normally defined as houses with less than 1800 square feet, excluding a basement. These house are also space efficient and less expensive to build on a small plot of land.