ROOF DECKS
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ROOF DECKS
Objectives:
• Functions of Roof Decks
• Types of Decks
• Slopes and Drainage
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Deck Function
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FUNCTION
As part of the roof assembly the deck should
be designed to provide:
Structural support
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Structural Support
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Structural Support
A deck transfers the weight of live and dead loads
to supporting framing members.
• Joist
• Purlins
• Subpurlins
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Example of a PURLIN
Sub
Purlin
Purlin
What’s wrong with this picture?
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Structural Support
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FUNCTION
Dimensional Stability
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Expansion Joint on a Road.
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Dimensional Stability
Decks must Accommodate Building Movement
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FUNCTION
Fire Resistance
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FUNCTION
Attachment
Show Ballooned EPDM
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ATTACHMENT
Did this deck stand up to the high winds?
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SLOPE & DRAINAGE
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SLOPE & DRAINAGE
Slope is provided by:
Sloping the structural framing
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SLOPE & DRAINAGE
Slope is provided by:
Sloping the structural
framing
Tapered insulation
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SLOPE & DRAINAGE
Slope is provided by:
Sloping the structural framing
Tapered insulation
Insulating fills
Expanded Polystyrene (EPS)
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SLOPE & DRAINAGE
Slope is provided by:
Sloping the structural
framing
Tapered insulation
Insulating fills
Combinations of the
above
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SLOPE & DRAINAGE
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DEFLECTION
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DECK DEFLECTION
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BUILDING & ROOF MOVEMENTS
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Video
Welcome to Canam1
EXPANSION JOINTS
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EXPANSION JOINTS
What should be considered in the design and
placement of expansion joints?
• The building's thermal movement
characteristics
• The structural supports and roof deck
• The roof system selected
• The climatic conditions
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EXPANSION JOINTS
Where should we install expansion joints?
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AREA DIVIDERS
Also called ‘Control Joints’ or ‘Relief Joints’
What’s the difference between an expansion joint and
area divider?
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DECK TYPES
The most common types are:
• Cementitious wood-fiber deck panels
• Lightweight insulating concrete and fills
• Poured gypsum concrete
• Precast gypsum panel
• Steel
• Structural concrete (cast-in-place, posttensioned and precast/prestressed)
• Thermosetting insulating fills
• Wood-plank and structural wood-panel decks28
STRUCTURAL CONCRETE
• The three general types of structural concrete
roof decks are:
– Cast-in-place - Concretes that are cast on a job-site
over form material and are reinforced with steel bar
and/or wire mesh embedded in a deck.
– Post-tensioned - Reinforcement cables or tendons
are tensioned after the concrete has been cast and
taken a set.
– Precast/prestressed - Cast at a manufacturing
facility and transported to a job site.
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STRUCTURAL CONCRETE DECKS
Cast in place concrete roof decks
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POST TENSIONED CONCRETE
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PRE-STRESSED CONCRETE
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PRECAST/PRE-STRESSED CONCRETE
1. THE FIRST STEP IN PRETENSIONING IS TO STRETCH THE STEEL PRESTRESSING STRANDS TIGHTLY
ACROSS THE CASTING BED.
2. CONCRETE IS CAST AROUND THE STRETCHED STRANDS AND CURED.
THE CONCRETE BONDS TO THE STRANDS.
3. WHEN THE STRANDS ARE CUT, THE CONCRETE GOES INTO COMPRESSION AND THE BEAM
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TAKES ON A CAMBER ENABLING THE MEMBER TO ACCOMMODATE GREATER LOADING.
PRESTRESSED CONCRETE DECK
UNITS
HOLLOW CORE SLAB
SOLID SLAB
DOUBLE TEE
Mr. T
SINGLE TEE
Wake up fool
& listen to the
instructor!
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Lightweight Insulating Concrete
Expanded Polystyrene (EPS)
Expanded Polystyrene (EPS)
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Lightweight Insulating Concrete
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PRECAST CONCRETE
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PRECAST CONCRETE
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DECK TYPES
Cementitious wood-fiber deck panels
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Cementitious Wood-Fiber Deck Panels
• Lightweight insulating concrete & fills
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DECK TYPES
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WOOD-PLANK DECKS
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TONGUE & GROOVE
Groove
Tongue
Bead
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WOOD-PLANK DECKS
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PLYWOOD & ORIENTED STRAND
BOARD (OSB) DECKS
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WOOD DECKS
Fire
Mold
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STEEL DECKS
Show: N.J Roofers Falls 40’
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STEEL DECKS
Flute
Flange
Flange
Rib
Rib
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STEEL DECKS
Rib
Width
Flange
Dimension
Rib
Depth
Web
Rib Spacing
Flute
Rib
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STEEL DECKS
30”
Approximately
6”
1 ½”
Nominal
3/8” Minimum
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STEEL DECK
30”
1 ¾”
6”
1 ½”
Nominal
½” Minimum
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STEEL DECKS
30”
2 ½”
6”
1 ½”
Nominal
1 ¾”
Minimum
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STEEL DECKS
Approximately
8”
3”
Nominal
1 ½”
Minimum
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STEEL DECK REPAIRS
Metal deck panels with multiply
openings may require
supplemental framing designed
by an engineer
Attach plate to
deck (4 Fasteners
Minimum)
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WOOD NAILERS & CURBS
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Thank You
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