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ROOF DECKSROOF 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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FUNCTIONAs 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 SupportA 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

What’s wrong with this picture?

Purlin

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Structural Support

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FUNCTIONDimensional Stability

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Expansion Joint on a Road.

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Dimensional StabilityDecks must Accommodate Building Movement

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FUNCTIONFire Resistance

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FUNCTIONAttachment

Show Ballooned EPDM

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ATTACHMENTDid this deck stand up to the high winds?

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SLOPE & DRAINAGE

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SLOPE & DRAINAGESlope 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 & DRAINAGESlope is provided by:

Sloping the structural framing

Tapered insulation

Insulating fills

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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

Video Welcome to Canam1

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EXPANSION JOINTS

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EXPANSION JOINTSWhat 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 JOINTSWhere should we install expansion joints?

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AREA DIVIDERSAlso called ‘Control Joints’ or ‘Relief Joints’What’s the difference between an expansion joint and

area divider?

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DECK TYPESThe 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, post-tensioned and precast/prestressed)

• Thermosetting insulating fills

• Wood-plank and structural wood-panel decks

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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

3. WHEN THE STRANDS ARE CUT, THE CONCRETE GOES INTO COMPRESSION AND THE BEAMTAKES ON A CAMBER ENABLING THE MEMBER TO ACCOMMODATE GREATER LOADING.

2. CONCRETE IS CAST AROUND THE STRETCHED STRANDS AND CURED.

THE CONCRETE BONDS TO THE STRANDS.

1. THE FIRST STEP IN PRETENSIONING IS TO STRETCH THE STEEL PRESTRESSING STRANDS TIGHTLY ACROSS THE CASTING BED.

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PRESTRESSED CONCRETE DECK UNITS

SOLID SLAB

HOLLOW CORE SLAB

DOUBLE TEE SINGLE TEE

Mr. T

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 TYPESCementitious 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

Tongue

Groove

Bead

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WOOD-PLANK DECKS

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PLYWOOD & ORIENTED STRAND BOARD (OSB) DECKS

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WOOD DECKS

MoldFire

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STEEL DECKS

Show: N.J Roofers Falls 40’

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STEEL DECKS

Flange

Rib

Flange

Rib

Flute

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STEEL DECKS

RibDepth

Rib

Rib Width

Web

Rib Spacing Flute

DimensionFlange

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STEEL DECKS

30”

3/8” Minimum

Approximately6”

1 ½”Nominal

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STEEL DECK

30”

1 ¾”

½” Minimum

6”

1 ½” Nominal

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STEEL DECKS

30”

6”

1 ½” Nominal

1 ¾” Minimum

2 ½”

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STEEL DECKS

1 ½”Minimum

Approximately8”

3”

Nominal

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STEEL DECK REPAIRS

Attach plate to deck (4 Fasteners Minimum)

Metal deck panels with multiply openings may require supplemental framing designed by an engineer

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WOOD NAILERS & CURBS

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Thank You