I use a unit system for every building I design even in renovation of existing structures.   I select a unit based on the materials selected before designing and many other reasons.   It provide unity in the design as it is developed.  As you work out a design you will make 10,000 choices.   With a unit system as an organizing guide the choice of say where to locate a wall can be made on the unit or half unit or quarter unit.  Or if there is a specific location that is not on any of these, that is ok.  The unit will just give you organization without really thinking about it.  I believe that with the unit system a unity results in the architecture that is more satisfying to humans.   It approaches the order and unity we experience in the natural world.  It is implicit and as human beings we have come to see this as satisfying and beautiful.  Nature is the great guide and teacher. 

I make a unit system choice very early in the design process.   As the design is worked out in the first drawing, it is worked out on a unit system.  This drawing starts after I have a general organization of the areas of the design (the PARTS) and after I have a general conception formed in my mind.  So when I start to draw the plan I already have a vision of what this design will be and how it is organized.   The drawing is to work it out in detail.  I first choose a unit system that will facilitate the design conception that is in my mind.  I put the unit system on the site plan and these days it is drawn on a separate layer on the CAD drawing.  The floor plan is started on a separate layer over the unit system and over the topographical survey layer. 

Later these units are numbered on each unit line one direction and letter on the other.  What I have is a mapping grid.  This comes in handy later when I need to describe a location in plan, I just call out the units R-19 and there is no confusion about it.

During the design of a building there are always choices of where to locate walls and features in the plan.   The unit system provides location choices.  I center the interior walls on the unit line or the half unit.  If there is a good reason I go off the unit.  The unit system is not rigid but only a way to provide unity to the whole.   Just by relating things to the unit lines as I design there are a lot of happy accidents later on, things just work without even planning for them because of the relationship to the unit made before.

The vertical unit can work the same way.  It is based on material choice.  For example a concrete block structure.  The block unit is 8 inches high (7 5/8” plus 3/8” mortar joint) so the vertical unit would be something that related to this.  The unit is usually not a single block but larger, say 16 inches for the concrete block.  The 16 inch unit works for modular brick coursing as well.  Six bricks with 3/8" mortar joint will course out at 16 inches. 

Most interior doors are 6'-8" in residential construction.   As you can see this works into five 16 inch vertical units.  I have used a wood interior wall system that is made from 4 by 8 sheets of 1/2" plywood.  I cut the plywood in 16 inch wide by 8 feet long.  I apply them horizontally and stagger the vertical joints.  The horizontal joints are covered by a batten that is 5/8"x 2 3/4" wide or the width of a standard light switch plate on the hourizontal.  These battens make the base board and work out so they also make the head trim over the door as they go up the walls.    I miter the outside corners of both the plywood and the battens. 

I would use a square unit system for a design that may have arcs or circles and for any 45 degree diagonal elements.  If the design conception I have in mind is going to be worked out on a 30 or 60 degree angle I would use an equilateral triangle unit.  

If I was to do some kind of free form plan or shapes I would use a four foot square unit so I could see the general size as I worked out the plan.  The unit system provides a visual scale without having to measure.     If you design a plan without a unit you will no doubt pick even feet for your sizes just because you have no other reason.  The unit system will provide you with choice points on the unit or half unit.    The result as I have said before will work out later on much better with a unit system.   Walls and elements of the design will just line up like magic.    The unit system will help you see the whole plan as you design even before you draw it.  You can plan ahead in your imagination as you look at the units.   

The unit system is like the musical scale.  The twelve tone scale allows the composer to create any kind of music, it just gives it some order and structure.   The same is so with the Organic unit system.   You can still create any kind of architecture, it will just have more order and each part will have some relationship to the whole.  I believe this is what we humans call beauty.  Try it.

James Schildroth, Architect