Construction drawings, schedules, and specifications are created after the design is complete and the client has approved the design. These construction documents put the designer's plan into action.
As a designer, you'll need to be able to read and interpret construction documentation, including drawings and specifications. You'll also need to be able to create them using industry standards and drawing conventions. Construction documents are contract documents.
While you might come up with innovative interior design ideas, you must first communicate them to your client. Next, you must communicate your instructions to the construction crew building your design solution.
There's a saying about “talking the talk” versus “walking the walk.” It means you need to support what you say not just with words but through your actions. In construction and interior design, these actions or instructions come in the form of contract documents.
Your knowledge of construction documents is critical to your success on the NCIDQ Exam and as a professional interior designer.
Construction drawings rely on precision. So the drawings you create need to be as accurate as possible, within the tolerances for the intended use. Sometimes you'll be working with as-built plans from an architect or local building office. If not available, you'll need to measure the existing space to create your floor plan.
As-Built drawings are essential for two reasons:
- The as-built drawings form a record for the design of future changes or additions to the space.
- The as-built drawings can also be valuable to the operations and management team. For example, these drawings show the location of critical control system sensors and shut-off valve locations.
The contractor keeps a master set of as-built drawings on the construction site for recording any changes. These manually marked-up drawings are called red-line drawings. Each contractor and sub-contractor verifies installation per the original drawings or records the changes. Changes are usually marked in red ink, thus the name.
After construction, all red-lined changes are transferred to the finalized drawings. These changes use the designers’ original drawing files as the starting point. Finally, the updated as-built drawings are submitted to the owner as a part of the project close-out process.
When you're studying, be sure to become familiar with all the different types of construction documents. If you don't work on drawings in your job, it may be harder for you to understand the differences. Ask your manager how you can contribute to a project and work with a set of construction drawings.
Measuring conventions & construction drawing standards
There are several tools and approaches to measuring a space. You'll need to be familiar with each and know the level of accuracy required for which types of project. In addition, you'll need to understand which appropriate measuring conventions apply to a particular project and the construction drawing standards used.
- Tape measure
- Electronic distance measurement (EDM)
- Reflectorless electronic distance measurement (REDM)
- Rectified photography
- Convergent photogrammetry
- Laser scanning
Although projects vary, common standards apply to construction drawings in terms of:
Drawing sheet size
The sheet size is determined by the extent required to draw the floor plan on a single sheet of paper. Standard sheet sizes are based on three systems:
- ISO (metric)
Title blocks contain information about the project as well as data specific to each page. Some examples include:
- Sheet number
- Sheet name
- Contact information for designers, consultants, and owners
- Project title
- Project number
- North arrow
- Key plan
- Space for drawn/reviewed by
- Revision date
After the cover sheet or title/index sheet, the General Notes pertain to the entire project as a whole. For example, one or more sheets are dedicated to general notes in a set of construction drawings. Examples could include:
- General summary/description of the work
- How pricing and payment will be managed
- How alternates are to be handled
- Contract modification procedures
- Sample/shop drawing submittal procedures
- Final cleaning and jobsite protection
Most firms organize drawings based using either of these two standardized methods:
Uniform Drawing System UDS or
Construction Specifications Institute (CSI).
Both methods include these commonalities:
Borderlines— typically 1/2″ or 3/4″ wide on the top, right, and bottom edges. The left edge needs 1-1/2″ for binding.
Title block — usually located on the right side. Most title blocks are about 6 x 6 inches but will vary from firm to firm.
A demolition plan illustrates which existing construction components will be removed and which will remain.
Some projects are not complicated, and only a small area is to be demolished, like a partition. This can be shown on the construction floor plan in a dashed line versus a separate demolition plan.
Complex projects need separate demolition plans (s). Demolished components also need to be dimensioned, just like with new construction.
Floor Plans and Elevation Drawings
Floor plans, often called space plans, show a view of a space from overhead, as if the building were sliced horizontally 4 feet above the ground level.
Floor plans show the building configuration, including all existing components, as well as
- new partitions
- built-in components
- floor material
- room names
- symbolic reference to any elevations / sections /detail views
- special notes or equipment
Depending on the project size, floor plans are drawn to a scale of 1/8″ or 1/4″ = 1′-0″.
Elevation drawings show vertical surfaces from a straight-on view, without distortion. They can show wall surfaces, openings, built-ins, and locations for light switches or thermostats.
Elevations may reference other drawings, such as detail drawings and sections, to further clarify the design.
Elevations are typically drawn at a scale of 1/4″ or 1/2″ = 1′-0″.
An egress plan for every floor must be part of the construction documents. Egress plan drawings need to show all portions of the means of egress, including code requirements for:
- occupant loads
- number of exits
- width of exits
- common paths of egress travel
- travel distances to an exit
Reflected Ceiling Plan
A reflected ceiling plan (RCP) shows the entire design of the ceiling. The RCP is drawn in the same orientation and scale as the floor plan, from an aerial view as if the ceiling is transparent.
An RCP is critical for coordination with other trades. For example, designers will coordinate with HVAC, electrical engineers, and lighting designers. The RCP is used to show these building components viewed together to ensure no conflicts with the location.
In smaller residential projects, RCPs may be combined with Lighting and Electrical drawings. For more complicated projects, the RCP, lighting, and electrical drawings are typically separate.
A reflected ceiling plan shows any walls that touch the ceiling or extend through it. It also illustrates the layout of:
- ceiling materials
- sprinkler heads
- smoke detectors
- air diffusers/vents
- access panels
- light fixtures, including emergency lights
- light switching (depending on the project- sometimes on electrical drawing)
- reference key(s)
- critical dimensions are indicated, as well as changes in ceiling heights
The drawings on the detail page communicate the designer's vision to the contractor and trades. Detail drawings are true to their name. They show how the assembly and connection of several components — how the design can be built. One example is the detail of a coffered ceiling.
Because they can be quite complex, detail drawings are drawn larger than the floor plan. Typical scales range from 1″ = 1'0″ to 3″ – 1'0″. Half-size and full-size drawings are common too.
Other Contract Documents
Construction drawings aren't the only type of contract documents you'll use and be tested on. Others include schedules and specifications.
Schedules in construction documents deal with information. Schedules show complex information in a chart format, so it's easy to read and understand.
Each entry has a numeric identifier and attributes associated with it in each of the columns. For example, typical schedules used in interior design include:
- Door schedules
- Finish schedules
- Hardware schedules
- Millwork schedules
- Kitchen equipment schedules
Construction specifications aren't part of the construction drawing set. Instead, they are part of the project manual.
Construction specifications instruct contractors on what materials will be used and where. Like the drawing set, the specifications are available for contractors to review before bidding on a project. In addition, the specifications are usually required by the contractor to provide an accurate quote.
There are several different approaches to writing specifications. Some are broader and allow for interpretation. Other specifications are very detailed. The interior designer should understand the difference between the different types of specifications. The designer should also understand when and where each type of specification is most appropriate.
Here are three popular specification types:
These specifications tell the contractor precisely what product/material to use. Prescriptive specifications are also called “closed specifications.”
1. Proprietary specifications
This type of prescriptive specification calls out a specific manufacturer's product by name or model number. These are the most restrictive specification type.
Base bid specifications are a type of prescriptive spec that states a proprietary product. The difference is that the base bid specification allows for substitutions by the contractor. These specifications must be of equal quality and approved by the interior designer.
Ensuring quality product installation can be done through specifications, but what about the construction and installation quality themselves? Performance specs state the results from a specified item but allow the contractor to find the solution. Performance specifications are also called “open specifications.”
3. Reference standard specifications
These specs describe a material, product, or process using criteria or requirements set by a trade association, accepted authority, or test method. These criteria are reference standards.