Building plans are a graphical representation of what a building will look like after construction. They are used by builders and contractors to construct buildings of all kinds. Building plans are also useful when it comes to estimating how much a project will cost, and preparing project budgets.
The creation of a set of building plans starts when an owner or developer approaches an architect with an idea for a new building. The architect issues a proposal for his services based on the type of project and the owner's description. The cost for plans typically ranges from 3-5% of the total cost of the project. Once the owner signs a contract with the architect, the design phase begins.
On larger projects, the design process goes through several distinct phases. It starts with a schematic phase, where the architect captures the basic information about the project and creates simple floor plans to reflect this information. After the owner reviews these drawings, the architect proceeds with a more detailed set, called the “Design Development” phase. This process continues through a 50% drawing phase, a 90% drawing phase, and a final construction set. After each set of plans is created, the owner is given a review period, and his comments are incorporated into the next phase.
Once the building plans have been finalized, they are put out for bid. During the bidding process, contractors and subcontractors review the plans and submit their price to complete the work. Most of the time, the job is awarded to the lowest bidder, but this is not always the case. Owners may also take experience, schedule, and relationships into account when awarding a project.
Building plans may consist of a single drawing, or hundreds of pages. For larger or more complex projects built in the US, the drawings are often arranged in a specific order, based on a system developed by the Construction Specifications Institute (CSI). According to the CSI system, sets of plans start with a title page, which shows a list of all included drawings and well as a symbols legend. This page is followed by civil, or site, plans; architectural drawings; mechanical and electrical plans; then any specialty information, like sprinkler systems, special equipment, or furnishings. Other countries may have their own standardized systems for building plans.
Most sets of plans are accompanied by a specifications book, or spec book. This manual is organized in accordance with CSI codes, and contains information on materials and methods to be utilized when completing the project. It is critical that the spec book is used in conjunction with the project drawings, and there may be information in one that is not shown in the other.