Construction drawings are a set of plans and specifications which are used to carry out the agreed upon design ideas. These plans are usually the ones submitted to governmental agencies for review and approval. Contractors use these drawings to bid projects by calculating costs for materials, labor, overhead and profit.
Most people do not realize that plans and specifications are legal documents! They are part of the construction contract. “I give you money and you build this.” The purpose is to show what is to be built, while the specifications focus on the materials, installation techniques, and quality standards.
Construction drawings consist of architectural drawings (design, lighting, doors, windows, finishes, etc), engineering drawings (structural), mechanical drawings (HVAC, plumbing), civil engineering drawings (site grading and drainage), etc. There may be separate specialized drawings for kitchens and bathrooms.
These drawings provide all the information, both graphic and written, about the project. It is specific information. For example, the paint color to be applied to the walls will be listed by manufacturers name, the paint color number and name, and type of finish (latex, enamel) to be used.
Detailed information is given about everything in the project. Walls, doors, furniture, equipment, lighting, outlets, and so on, are all specified. Graphic symbols are used to represent walls, doors, furniture, etc. Dimensions are used to define the location of these components.
A door or window schedule is a chart that lists each one, where it goes, manufacturer, size, specific details (frosted glass, etc.) Text is used to further describe them or to point specific elements of the design. Legends are used to describe finishes, colors, lighting, etc. The elevator! Hopefully we can delay that decision for a few years.
The specifications are as integral to the the construction drawings as the drawings themselves. What quality of galvanized material should be used? Should the bolts be stainless steel? What is the quality of the concrete for the piers? These highly detailed bits of information are usually in the specifications.
The specifications can call out that materials are to be installed as per manufacturers specifications, such as “grinding all metal welds smooth”, the quality of construction, insurance the contractor shall have for his business, employees and subcontractors, who pays for permits, etc.
After the preliminary drawings are complete and approved by the home owner the construction drawings can started. It is assumed that the basic design concept will not change after approval of the preliminary drawings. This is the stage we are at right now.
The difficult part for us is picking out the finishes to the flooring, lighting, paint colors, bathroom cabinets and all of the kitchen appliances and counter tops, and much more. These choices are the place where we can save money or splurge on things we want. This is usually where budgets get blown!
We can use “add alternates” or “deduct alternates” to manage some of the costs. The “add alternates” can be items included in the design but the cost is priced out separately so the item can be excluded from the contract if the costs come in too high. An “add alternate” may be an upgrade from a gravel driveway to a paved driveway. A “deduct alternate” may be the elevator. If the bids come in above budget, the separate price (and work) for the elevator can be removed from the contract.
When we finish all (ha!) changes, we will submit our drawings to the City of Marathon for their input. Hopefully this preliminary review will pass and we don’t have too many required changes.
That review will give us confidence to go to contractors to get a preliminary cost estimate. Using construction drawings for preliminary bids is usually a little late in the process. If we are way over budget we need to redo all the construction drawings and go back to the preliminary drawings. Some contractors we spoke with wanted more information than a preliminary drawing would have.
We feel we are designing a “small” house, 36 feet by 36 feet. With all of the special requirements of the Florida Keys, we may be sorely disappointed. We will see.