TACTICAL DIAGRAMMINGRoofs and Vents

Roofs One of the two most conspicuous

features Some are characteristic of building use Often used to change the appearance of a

house without changing the floor plan Contain features that can identify walls,

bathrooms, kitchens, living spaces, etc. Roof profiles

All roofs are slanted Pitch of the roof can identify living space Color and shape of roof can identify

additions and remodeling Vent pattern can identify identical floor plans

Gable roofs• Most popular roof for

housing in America• 4-12 pitch most common in

warm climates• ≥ 6-12 pitch in colder climates

• The steeper the pitch the more likely there is to find a living space under the roof

• Nomenclature for all roofs• Gable• Eave• Ridge or Peak

GableEave

Ridge or Peak

Hip roofs• Second only to gable roofs in popularity for

houses• Seldom steeper than a 4-12 pitch

• Gables “tipped in”• Especially popular in high wind areas• Virtually never have a living space immediately

under the roof (attic area)

Shed roofs• Common for “out buildings” and over porches,

patios, carports, garages and • Tend to be very shallow, often less than 2-12 pitch

• Never have a living space immediately under the roof (attic area)

• Visible vents and ducts are almost always over the appliance being serve

Gambrel Roofs• Sometimes called a “barn” roof• Not uncommon for houses, especially in

areas with heavy snow or rain• Popular where zoning requirements limit height of

buildings

• Living space under theroof is nearly certain

• Consider the “attic” a second-story• Nearly always a sleeping area

Mansard Roofs• Sometimes called a “French” roof• More common for small retail and commercial

buildings• Seldom seen on American houses• Usually older homes, especially older, large Victorian

style• Living area under the roof nearly certain• Consider the “attic” a

second story—almostcertainly a sleeping area

Monitor Roofs• Popular on houses in very sunny climates

• Especially luxury homes

• Used for solar panels, windows and skylights• Often facing south to maximize sun orientation• Cathedral ceiling is near certain• Living space may

be under thehigher roof plane

• Lower roofplane usuallyhidden from street side

Dormers• Framed structures that project

from a roof• Used to add light and ventilation• Used to add living space

• Two styles of dormers predominate• Gable—Look for windows, especially openable• Shed—Nearly conclusive of a living space under the roof

• Some dormers are merelydecorative

• Dormers with windows arenearly diagnostic of a livingspace—almost always a sleeping area

Vents and Ducts• Vents are used to get rid of smelly odors, carbon

monoxide, cooking oils, fumes and the like• Most vents exit the dwelling

through the roof• Stove vents often exit through the

roof but frequently exit through thewall nearest the stove

• Some ventilation vents are installedat the top of the gable

• Vents are extremely useful for tactical diagramming because they are most often hidden inside walls

• Two types are valuable for tactical diagramming• Water appliance• Combustion

Water Appliance Vents• Necessary anywhere there is a drain

• Typically installed directly above waterappliances like sinks, toilets, bathtubs,showers, etc.

• Vents are the smallest on the roof• 1½ʺ pipe approximately 6-12ʺ above

roof through a metal flashing• There is never a cap or cover• Shadows may be more visible than the vents

• Extremely reliable because they usually exit the roof directly above the drain (inside the wall)

• Single exception is a “stacked vent system”• Distinguished by notably larger pipe

(≥ 2½ ʺ) and are usually on the hidden side of the roof and near the peak

Combustion Vents• Used for any appliance that needs

an exhaust for carbon monoxide• Furnace, gas water heater, etc.

• Usually the largest vents in the roof• Often as much 6ʺ in diameter and 2ʹ or more tall• Older homes may have clay pipe or asbestos but modern

codes will require double steel wall or even triple steel wall

• These vents are always capped to keep to allow exhaust but keep water out

• Not as precise as water appliance vents but will provide general locations

• The closer to the eave or the flatter the pitch the more likely that vents will be over the appliance

Vent Patterns• Kind of like a “fingerprint” for a house

• Not unique, but will identify same floor pattern• Once a floor plan is identified features from one

structure can be used to predict those in another• The buildings may not be adjacent to one

another or even appear similar• The more features that are used the more

reliable and precise the diagram

QUESTIONS?