TACTICAL DIAGRAMMING

WHY IT WORKS

Three components of Tactical Diagramming• Science

• Planning and building codes• Terrain Analysis

• Skill• Building practices and

tactical diagramming practice

• Art• Personal intuition, imagination

and ingenuity• A technique—not a tactic!

• Procedures for performingspecific tasks or functions

Building Codes• National Building Code of Canada

• Adopted in 1941• Originally instituted for fire

prevention and escape• Model code rather than

regulatory but usuallyadopted locallyas requirements

• Local zoning ordinances

Reverse Engineering• Mentally disassembling a house to

visualize the interior• Knowledge of building code requirements

helpful but not essential• Familiarization with building practices is largely

already available• Personal experiences and observations

• Especially useful for police and military• All buildings are built for a purpose and many

are altered to suit particular uses

Building Practices• Driven by economic

and aesthetic factors• Size and shape of house

and organization of rooms• Expense of installation

and cost of materials• Cultural conventions• Enables mass produced goods and

components• Examples include window coverings, hardware,

cabinets, furniture, plumbing fixtures, and so forth• Some have been incorporated into local

ordinances

• Just as influential as regulations• Tend to be universal rather than regional

Building Principles• Four elements that must be controlled

• Fire, Wind, Water, Gravity• Use of building will strongly influence

construction• Buildings are hollow

• Limitations on span by materials and expense• Nearly all residences in America are "stick

framing"• Interior walls are used for intermediate support

• Bearing walls are more predictable than partitions

Coup d'oiel• French—"The vision behind the eye"• English translation—perceptive insight

• An ability to "see" on the other side of the hill or inside a house

• Part artandpart science

Helpful Hints• Work from large to small

• Start with orientation• Next go to building outline• Diagram floor plan last

• Work from confidence to ambiguity• Sketch in as many features that can be reliably

placed and sized first• Compare

• What you know or believe to what you see• Be suspicious—explain incongruities• Don't be afraid of "I don't know!"

Residential Trivia• Size of house ~2,450 square feet (median)

• Typical three-bedroom in Southwest USA is about 1,400 sq. ft.

• 80% built since 1920• About 2/3 will have an attached garage or

carport• Almost half will have a separate dining room• More than 2/3 are occupied by the owner• More than 3/4 are single-family structures• Approximately 90 million homes in USA

• Each has more in common with the others than differences

Frequently Asked Questions• Why focus on residences?

• Most common target for warrants• Public buildings provide far easier access to gain info

• How long does it take?• Varies with amount of desired detail and complexity of

building• Generally, figure 60-90 minutes for most applications

• How accurate can a diagram be?• Depending on resource photos, as close as six inches for a

room and a foot for a building• Features can be precise!

• Many features, like doors and windows, can be estimated within one inch

Useful Tools• ¼ʺ graph paper

• Good scale for nearly all diagrams• Mechanical pencil with HB lead

• Soft lead with dark lines but easily erased• Compass or dividers

• Easy and accurate transfers of scale

• Gum eraser, especially pen style• Computer software

• By far, the easiest and simplest method for diagramming• Some are automatically defaulted for sizes and

codes• Provide instant 3D versions, including walk-throughs

• Sketchup—free version from Google• Chief Architect—Better Homes and Gardens• Punch Pro—Punch Software, less than $100

Useful Books• Look for illustrations as

well as narrative• Comprehensive

overview is better than detailed information

• You don’t need to read them, you’ll use them for reference and precision

Tactical Diagramming Book• Used as text for this course• Written from a tactical

perspective rather thana builder’s

• Heavily illustrated withexamples, graphics,photographs, etc.

• Focused entirely on tacticaldiagramming

QUESTIONS?