Chapter 2 illustrates a new method for identifying modular relationships within a building system. The new method furthers the work of the European Productivity Agency (between 1953-1961) by including space required for making adjustable connections between parts.

1. B A B A BB A B A
BABABBABA
A AAA
AAAA
Chapter 2
(n)A+(n-1)B
The Story of Patent US 8,353,131 B2

2. (n)A+(n-1)B − The Story of Patent US 8,353,131 B2
Part One − A New Modular Theory
This story is an
illustrated explanation of
THIS
...an adjustable
mechanical connection.

3. I need a UNIQUE and
INTERESTING
AFFORDABLE home

4. STICK-FRAMED MODULAR!
Hmmmmm...Not very
Interesting. And they all look
sooo similar...
Sigh.

5. OF COURSE!
Architecture! Creative designs,
unique appearances,
and the latest technology...

6. STICK-FRAMED
MODULAR!
Whaaah?
But that’s not
new...it’s the
same thing the
other guy had.
Sure, with a
at roof and
nicer materials,
it looks
imaginative...
yet, it costs
much more!
Circa 2002-2012. Stick-framed modular “PREFAB” is widely
considered to be the state-of-the-art of affordable housing
technology.
*
Aww. It seems the
“new technology”
is only skin
deep...sigh.

7. ...afterall,
we’ve been
stick-framing
since the 1840s*
...sigh.
* Stick-framing, or wood light frame construction, was introduced in Chicago in the 1840s. Today, with only slight
variation from its inception, the US house building industry relies entirely on this method to produce the nation’s
housing stock. Whether stick-framed, modular, or prefab, it’s all the same; and it’s expensive.
There’s got to
be an affordable
modern way to
build a unique
modest house...

8. ...not custom-cut,
not custom-t.
Not custom at all.
But READY-MADE and
INTERCHANGEABLE!

9. INTERCHANGEABLE PARTS!
With interchangeable parts, I can
create MY OWN unique look and layout.
Well...the auto industry uses
interchangeable parts.
I’ll start with the basics: a CHILTON’S*
*The Chilton Publishing Company, began offering illustrated repair manuals to small car dealerships, service stations, and repair
shops during the 1920s. Chilton’s Auto Repair Manuals were printed until 1996 and featured service information for thousands of car
makes and models over seven decades. From service and repair to a complete teardown and rebuild of a vehicle, Chilton’s Auto
Repair Manuals today provide do-it-yourself automobile repair instruction for classic car enthusiasts worldwide.

10. Hmmm...
...that’s how
ready-made INTERCHANGEABLE
parts are joined.
...ADJUSTABLE FIT!!
Correct t is adjustable between
serviceable parts.
That’s it!!

11. Correct t is adjustable
in the auto industry.
...with adjustable t between
parts, cars can be built from
ready-made (prefabricated)
INTERCHANGEABLE components.
*This illustration depicts an image which appeared in the book Refabricating Architecture by
Stephen Kieran and James Timberlake under the caption “The Art of Joinery”. Below the image
is written: “In construction, architects are happy to receive half-inch tolerances. In the car
industry, precision is measured in millimeters”.
MEASURING PANEL GAP*
Auto body panels are adjustable. Correctly aligned panels are
separated by panel gaps of consistent width. Correctly spaced panels
ensure that doors may swing in/out of the gap without bending
adjacent panels. Correctly spaced panels also ensure correct t and
operation of weather seals for water diversion.
DOOR STRIKER AND
CAGE PLATE
...and because t is
adjustable between parts,
cars are serviceable!
Auto body panels are adjustable. Fit is adjusted with
shims, spacers, and cage plates. The door lock striker,
for example, secures a closed door in tted position. It’s
connection is made with a cage plate—a threaded plate
that “oats” to a desired position prior to tightening.

12. A mechanical connection is one that relies
on mechanical fasteners, hardware, or a
combination of both to join parts. An
adjustable mechanical connection enables
joined parts to be ready-made (prefabri-
cated), interchangeable, and serviceable.
ADJUSTABLE
MECHANICAL CONNECTION
DOOR MOUNTING HARDWARE
Auto body panels are adjustable. Door panels are adjusted at the
door lock striker (previous page) and at the hinges. Door hinges
are fastened to the door and/or a body pillar with cage plates
(oating anchor plates). The cage plates allow the door and door
hinge to slide up/down, fore/aft and in/out, relative to adjacent
panels—ensuring that panel gap can be precisely dialed-in.
In the auto industry,
INTERCHANGEABLE PARTS
are fastened
with adjustable connections.

13. I wonder if the building
industry has ever considered
interchangeable parts.

14. ...this is amazing!
...following World War II,
eighteen countries worked
together to modernize their
building industries with the
development of standardized
Towards a
New Architecture,
Le Corbusier, 1927
*The European Productivity Agency was set up as a branch of the Organization for European Economic Cooperation in 1953. Underlying the group’s work was
this observation: “building materials are manufactured in an excessive and random variety of unrelated sizes.” Tasked with improving construction efciencies,
the group followed in the footsteps of 1930s building-material-standardization pioneer—Albert Farwell Bemis. According to the EPA, Bemis’ modular coordination
in building created “the method by which dimensions of building parts are coordinated to secure exibility in use combined with ease of production.”
They believed this “would enable a given stock component to be placed in a number of alternative positions either in the same building or in different
buildings.” For six years the group focused on the development of standardized and geometrically-related part sizes which would enable rapid assembly of
interchangeable building parts.
An Architecture of Parts -
Architects, Building Workers
and Industrialisation in Britain
1940-1970,
Christine Wall, 2013
The Prefabricated Home,
Colin Davies, 2005
The Prefabrication of
Houses,
Termed “MODULAR
COORDINATION in BUILDING”,
the group published a nal
report of their ndings in 1961.
Titled Second Report of EPA
Project 174*,
This report weighed-in on the
practicability of standardizing
interchangeable part sizes in
INTERCHANGEABLE parts.
the construction industry.
...I’ve got to nd that report!
Refabricating Architecture,
Stephen Kieran and James Timberlake, 2004
The Albert Farwell Bemis
Foundation, 1951

15. I’m trying to track
down an old book:
Modular Coordination,
Second Report of the
European Productivity Agency
Project 174.
Published 1961.
?
YES, we have that.

16. * Greece was a participating member of
the EPA’s Project 174, and constructed
nearly 600 new houses utilizing modular
coordination in a limited way. These homes
exhibited a 3-dimensional layout regulated
by a 2 meter X 2 meter X 2 meter modular
grid. After much research, the EPA settled
on a 4” module grid.
Regulating grids have long been
used to identify
structural and system efciencies
through repetition of common
dimensions. The EPA’s “module grid”
was equal in three dimensions.*

17. * Manufacturing tolerances are rules dening the precise boundaries or
limits of individual part sizes (what is too short or too long, too thin or
too wide, etc.) so that t can be ensured during assembly.
nM*
nMnM
...and to ensure that parts would t together in multiples—an extensive working
theory of manufacturing tolerances* was developed. The tolerances regulated the
physical size and theoretical placement of individual parts within the whole. It was
hoped that precise manufacturing would preserve working system geometries as
more-and-more parts were placed within a modular assembly.
nMnM
nMnM
* nM = Any number (n) of modules (M) required of a working modular
component size.
nMnM
SYSTEM TOLERANCES
(Illustration represents some of the
many rules for ne-tuning modular
part size and modular placement)

18. n is any number of
desired modules
3M + 4M did not equal 7M in practice.
t is tolerance: the
assurance for
correct part size
and placement of
components, at
least in theory.
3M 4M
Yet, even with rules assuring
for the modular coordination
of part size and placement,
unwanted “creep in assembly”
of multiples was unavoidable
on the job site―in spite of
precise manufacturing,
modular geometries
could not be maintained
as parts were joined.
modular
part 1
modular
part 2
While physical part size and
position were tightly
regulated, a universal theory
on jointing was unstudied.
Joints were assumed to be
ush (a dimension of zero), or
nearly ush (unresolved
dimension of zero), or a half-
module (a function of the
module without a separate
theory for modular jointing).
...And while ush joints may
work for Legos and other
small toys where water-tight
connections aren’t necessary,
ush joints leave no wiggle-
room in the large-scale world
and the imperfect nature of
building construction.

19. ...and with interchangeable parts I can create
MY OWN unique look and layout.
Our homes are an expression of individuality.
SO WHAT DOES?
Yet, history’s most comprehensive attempt
at creating interchangeable parts―the
EPA’s Project 174―didn’t work out.
NOT THIS:
BUT THIS:
These 3 ingredients and
a KEY hold the promise of
ready-made affordable
home assembly:
1.) modular coordination
with
2.) large gap between parts
with
3.) adjustable fit
INTERCHANGEABLE PARTS
Answer:
EPA Project 174’s modular
coordination with precisely-applied
manufacturing tolerances
to control part size and t.

20. With ready-made
interchangeable parts,
MASS-PRODUCED houses
can have their own unique
look and layout.
...they can be
affordably assembled and
PERSONALIZED.

22. and a
KEY

23. A ready-made
architecture of
interchangeability
is based on
geometrically-
related
components.
The 1st ingredient is
modular coordination.

24. Cabinet hinges
demonstrate how t can
be adjusted to position
individual ready-made
planar elements
correctly within their
own system.
Yet, is there an
example in the
building industry of
the adjustable t
of ready-made
multiples
The 2nd ingredient is
adjustable fit.
?

25. In other words, the problem of creep in the assembly of these
ready-made multiples is corrected by the mason as bricks are
stacked―with each joint presenting an opportunity to dial-in
t within the larger assemby.
JOINT SIZE IS FLEXIBLE. PART SIZE IS NOT.
Bricks are mass-produced. Correct t is assured―NOT due to
a shared geometry or modular unit size as often believed―but
because their joints are carefully adjusted by the installer.

26. A closer look shows that joint size is nearly 18% of unit―or part―size. This reveals that nearly
15% of a correctly installed modular brick wall surface is a exible joint.
ASTM C 652 allows for a deviation of 3/32”, or 2.5mm
from the standard 10mm bed joint size.
A standard modular brick is 2 1/4”, or 57mm. While a standard bed joint is 3/8”, or 10mm.
In practice, allowable deviation produces joints that may
vary up to 3/16” from one another (smallest at 9/32” and
largest at 15/32”).
...Further revealing that almost 8% of an entire wall surface
is routinely adjusted by a mason as the wall is installed.
While ush (Lego-like) joints
offer no means for adjusting t
between assembled parts
(in order to avoid assembly
creep)―large, adjustable joints
enable imprecisely
manufactured parts to be
tightly joined.
Large joints produce
large adjustability.

27. ABABA
ABABB
Masonry construction shows
that by holding parts away
from each other, the
space between can
be used for dialing-in t
as parts are placed...and
that large gaps create
large adjustability.
...Therefore, a working modular
system can be based on regulating
lines marking standard gaps ( )
at regular intervals. Each gap
identies space available
for making necessary adjustments
to the t of adjacent parts.
The 3rd ingredient is
make a gap!
B
A working modular system
Hold them apart:
MAKE A GAP!

28. B A B A BB A B A
BABABBABA
A AAA
AAAA
Regulating lines used to asign
modular part size(s)
independently of a standardized
jointing method do not work.
Flush Connections (No Gap)
Regulating lines used to mark
the location and limits of
standardized and adjustable
joints do work.
Standardized Gaps
MAKE A GAP!

29. * Ready-made (mass-produced) house describes an approach to home-building that has largely remained ellusive to the home building industry. The technology
has been sought after in the past as a means of providing modern affordable housing to the market. Almost without exception, there has not been a working
solution. The Lustron Corporation did come close however, and produced/shipped 2,680 houses of 3 varieties between April 1948 and May 1950 before the
company closed its doors. The houses looked quite similar and great variety was not a focus. A workable model―one that allows personalization rather than
made-to-order customization (i.e. interchangeable parts)―has never been fully contemplated. The European Productivity Agency’s Project 174 was on the right
track, yet a working theory on jointing was never developed.

30. The formula above describes
a method for standardizing
modular system relationships
based on connection size and
location. It is claimed as
Patent US 8,353,131 B2*
or,
part size = (n)A+(n-1)B
Modular part size(s) are a product of
standardized adjustable connections
at regular intervals.
PART SIZE IS A FUNCTION OF THE GAP!
KEY:
* Never before has connection size and arrangement of available connection locations been used as the precursor for identifying
modular dimensions and relationships. Rather than an afterthought, or ignoring needed connection space altogether (ush), the
connections between parts determine their size!