Developing a System to Produce Better Construction Documents – Part 2: Plan the Construction Drawing set ahead of time

To start with, you must realize that the set of Construction Documents that you issue is your firm’s product. This is what you are selling. It represents the building that you have designed, but the execution of the construction, the creation of the building itself, is done by someone else. The product that you send out the door is the CD set.

Of course, everyone knows how to put a set together. It is the thing that is a part of your “experience”. But it is also something that easily gets taken for granted. So, design it. Spend some time thinking about it.

If you have a pretty good set of drawings for a previous project or other, develop it as a model for new sets for new projects. Improvements can be made as things go along, without re-inventing the wheel, and you can end up with an even better than “pretty good” model set.

Construction Documents represent a major amount of effort, so take care to schedule the work. When you get into it, Google “Planning Fallacy” Here is a brief description from Wikipedia:

In other words, no matter what you think you know about how much time it took to put together a set the last time, you will optimistically imagine that it will take less time this time. The same effect is likely to affect all your consultants as well. You can look up the time records to give yourself a foundation for a reasonable estimate of time, but remember that it might not be predictive of the time you will actually consume! Making sure that you will have enough time to do the drawings and write the specs by being a bit pessimistic might even make it possible also to have some time to do proper drawing checking.

It seems obvious, but it is important to figure out how to determine when the set is done. A lot of this can be picked up by checking the drawings at an appropriate time, but it also demands the presence of mechanisms that will make it harder for the drawings and specifications to escape being finished.

If you would like to make the drawings take a little less time, think about producing fewer drawings. A typical set of drawings has dozens, even hundreds, of drawings. Perhaps it is because manipulation of the building model makes it easy to include drawings that didn’t used to make it into a set. My advice is to leave them out this time if you can. For example, I recently looked at a set for a renovation project that had extensively keynoted drawings of all exterior elevations --- the existing conditions. Every keynote started or ended with “(E)”. There was absolutely no new work described on these sheets. Interior elevations can also get out of hand. Many of the items that they depict can be handled with charts and table of typical conditions --- mounting heights, locations of switches in relation to doorways, toilet accessory locations, etc. --- showing every wall of every room is seldom necessary.

Also, there is often no need to reproduce manufacturer’s drawings except to make clear their interface with the things that you have designed.

One of the unexpected consequences of the move to Building Information Modelling, alias “BIM”, is what a friend of mine calls, “the illusion of finality”. Once the model is constructed, it looks done, finished, and all worked out. The details seem to look like they work (from a distance), and the promise of being able to identify conflicts between systems seems to suggest that they are, indeed, resolved. This effect is just a deepening of the vanishing dimension problem that appeared early in the computer drafting era: everything must be drawn correctly to fit into the model; if things are drawn correctly, they are by necessity the right size; all of a sudden, dimensions seem somehow redundant. But without them, the Contractor is likely to be lost in the field.

It is very important to include everything that is required to make the set complete. It is also important to have a set that is not only complete but finished. It can be a good idea to create the Table of Contents at the very beginning of the CD phase instead of at the end. A competent Job Captain can use such a framework not only to organize the work of the Architectural set but also Its relationship to the organization and content of the drawings of the other Consultants. The computer has made production fast, but it leaves too little room for coordination. Poor coordination is often the source of most RFIs, and a well-designed set can make a big difference.