Convenient Gaps In Construction Drawings
On a recent podcast with my one client, Chas Peruto, he mentioned my drawings had convenient gaps in them. What he explained that to mean is that the level of documentation in the drawings allowed his team of builders to have some flexibility in the construction of the building. Basically the drawings have just enough amount of information on them, but not too much information where each component needs to be perfectly installed for everything to work.
http://www.dauntlessdc.com/podcast/2019/09/25/rich-the-architect-episode-31
Level of Detail Required in a Building Drawing Set
When producing drawings for a construction project, there is a certain level of detail that is required for a building permit. This typically is not enough information for a contractor to build from. Usually the permit requirements are more big picture elements like occupant egress out of the building, fire rated walls, and structural framing. For a contractor to build a project properly, there is an additional level of detail needed for the contractor to understand the design intent. The contractor will need details of specific conditions like how to make the transition from a wall to a roof water-tight.
Critical Areas vs. Flexible Areas of a Construction Project
In that area of specific details is where the contractor typically needs the ability to be flexible. When providing dimensions on a floor plan, I was taught to either have a variable dimension in a string or a note to allow for unknown field conditions. If there is a critical dimension, simply indicate that area as critical. Usually an area that is not as critical is where a variable dimension is placed.
Tolerance of Construction Materials
In construction each material has a tolerance level for a contractor to build from. Masonry for example has a tolerance of around ½” for mortar joints and plumb alignments. The reinforcement elements in a masonry wall have a higher tolerance of around 1-1/4”. Steel tolerances vary from 1/16” to 3” depending on the type of connections and length of steel. The tolerances for any material also vary from an interior wall or element and one that is exposed to the elements on the exterior of a building.
Translating Construction Tolerances to Level of Detail
Taking the information from the material tolerances I then know what needs to be documented in a drawing set. Using the masonry example, there really is no need to dimension a wall to a ¼” or smaller dimension, since the tolerance is ½”. This also simplifies the math the contractor needs to do in the field. If a string of dimensions also has an open end to it, it further simplifies the math needed since the contractor has some wiggle room to work with.
Discovering New Design Features while Under Construction
The best set of drawings and 3D images or models still cannot compare to actually standing in the built space. I cannot even count how many times I have stood on a construction site with the contractor and owner and came up with a design solution that was never thought of during the design and drawing phase. The solutions made during construction usually are key to tying together the rest of the project’s overall design.
Finding that Balance
The balance between too much and not enough information in a building construction drawing set varies from project to project. Let us help you navigate that process and collaborate with you on your next building project.
Contact us today to schedule an appointment.