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.
Every set of custom house plans includes several items which need to be blown up and detailed for further clarification. If a set of plans does not provide additional close-up drawings (for things such as beam connections, deck railings, stairway construction, etc.), then it is not a complete set. It is very easy to cut corners during the planning process. But the end result will be higher costs for the home owner - and lots of frustration for the building contractor.
Moreover, you can save a lot on construction cost when a using a stock house plan. The advantage comes when you purchase a plan that had been previously used. This means all costs have been put into consideration, therefore, one can easily know what to expect come time for the actual construction. This gives an accurate budget, a small construction span, and efficiency due to prior arrangements during the recent use of the house plan.
Another service provided by the companies that design and sell house plans, is one that allows you to estimate the cost for building a particular house in your area of the country. The South is the least expensive area to build in and the West has the highest cost .The national average is somewhere in between.