Designing Rooftop Amenity Hardscapes

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• Intro/TOC
• Rooftop Evolution
• Technical Reference
• Material Selection
• Pedestal Selection
• Installation Concerns
• Vertical Elements

0:00 – 5:49: Intro/TOC

Unilock overview (3:35)

Learning objectives (5:03)

5:50 – 15:24: Rooftop Evolution

Brief overview of the transformation from ballast to programmed spaces

5 common roofing types used on commercial buildings:

• Ballast/single ply/liquid applied
• Extensive roof garden
• Pedestal roof deck
• Outdoor amenity space

Examples (7:10):

Ballast/single ply (7:10)

Still a commonly used system – not intended for people use.

Extensive roof garden – example: Lake Point Tower, Chicago (1969) (7:47)

The extensive garden roof is a much healthier and more functional roof:

• Creating habitat/restoration
• Filtration of acid rain and air pollutants
• Noise pollution reduction
• Therapeutic effects found from being in the presence of nature

However, the extensive garden roof can be costly to install and repair.

Pedestal roof deck (late 19880s to early 1990s) (8:50)

• Better than a ballast system
• More affordable than the extensive roof garden
• Not very aesthetic
• Lacked quality plant material

These roofs are usable but not very people friendly.

Green roofs – example: Chicago City Hall (2001) (9:36)

Using green roofs provides many ecological benefits, such as:

• Reduced energy consumption for heating and cooling
• Stormwater retention
• Heat island mitigation

These roofs often lack usable activity areas.

Combination amenity space and green roof – example: Cuyahoga County Headquarters, Cleveland, OH (early 2000s) (10:53)

• Ecological tray system for plant material
• Concrete slab access walkways and gathering areas
• Bench seating

These roofs often lack movable furniture and key vertical elements to better define space.

Reemergence of outdoor spaces – example: Old Mill, Toronto (11:28)

• Maximizes the unused roof space
• Provides activity space during seasonal weather
• Creates an opportunity for attracting tenants

A properly balanced combination of the extensive garden, pedestal roof deck, and green roof is essentially a "rooftop amenity space." It's the best of everything.

Example: 1035 W. VanBuren, Chicago (2017) (12:29)

Unilock's organic evolution in to the rooftop amenity market (12:58):

• Large-format concrete pavers
• Modular block seatwalls and planter walls
• Natural stone
• Porcelain tile
• Additional accessories such as pedestals

Project references (13:40):

• John G. Shedd Aquarium, Chicago (2019) (13:40)
• College of DuPage Culinary & Hospitality Center, Glen Ellyn, Il (2011) (14:08)
• Gateway West, Chicago (2015) (14:30)
• Private corporate headquarters, Arlington Heights, Il (2016) (14:55)
• One Federal, Boston (15:06)

15:25 – 33:27: Technical Reference

Basic industry knowledge

Structural and membrane (16:03)

Consider structural performance for existing buildings, review building code live load requirements before proceeding. Typical live load minimums for outdoor roof gardens is 100 psf.

Installation options (17:01):

The three systems primarily used on roof applications:

• Slabs on pedestals
• Most widely used
• Ease of maintenance
• Size limitations
• Slabs on granular base
• Oldest and most extensive
• Maintenance can be expensive
• No size limitations
• Slabs on permeable chips
• Supports heavier loads
• Improved drainage
• Blue roof

Components (18:45):

• Roof pavers
• Pedestal system
• Waterproofing and protection

Option 1: Pedestal over membrane (10:00)

Project references (20:19):

• Loews Hotel, Streeterville, Chicago (20:19)
• Bryn Mawr Country Club, Lincolnwood, Il (20:19)

Option 2: Slab on sand over insulation (20:53)

Project reference: Hubbard Place, Chicago (21:29)

Option 3: Slab on permeable base (22:48)

Project reference: 233 N. Michigan, Chicago (23:23)

Industry standards (23:47):

General overview:

• CSI Master Format Section 07 76 00 Roof Pavers
• 07 76 Roof Ballast Pavers
• 07 76 16 Roof Decking Pavers
• There is no ARCOM MasterSpec section listed for 07 76 00.
• Unilock offers roof paver specification on their website.

For concrete slabs:

• ASTM C1782 Standard Specification for Utility Segmental Concrete Paving Slabs

For porcelain tile:

• Center support recommended when elevated over 2 inches
• Break strength per ASTM C648 greater than 3,400 lbs.
• Freeze/thaw resistance per ASTM C1026

Four popular types of products (24:54):

• Concrete
• Price range from $3.50 to $11 per square foot as of presentation time
• Natural stone: 7/8 to 1 1/4 inch thick
• Price range from $8 to $50+ per square foot as of presentation time
• Porcelain tile: 5/8 inch thick
• Price range from $6 to $9 per square foot as of presentation time
• Wood decking (panel)
• Price range from $12 to $14 per square foot as of presentation time

Concrete manufacturing (26:00)

ASTM standard:

C 1782 Specification for Utility Segmental Concrete Paving Slabs

References: C1645 for freeze-thaw durability

ASTM Standard C1782 (26:35)

• 725 psi average
• 650 psi min. unit
• Height tolerance less than +/10.12 inches (3 mm)

Slab units larger than 101 square inches

Independent test results (27:23)

Practical test results (28:33)

Question: Does Chicago have a requirement that buildings need green roofs? (29:35)

Answer: Yes it does, along with a requirement for some buildings to have outdoor amenity space.

Question: What make and model of filter fabric do you use? (30:09)

Answer: It depends on the needs of the project.

Discussion of de-icing roofing systems (31:53)

Any substances containing magnesium can be extremely harmful to concrete.

33:28 – 48:56: Material Selection

Concrete, natural stone, porcelain

Concrete slabs (33:48)

Not all concrete slab aesthetics are "apples to apples." There are multiple surface finish options to consider:

• Mottled
• Blasted
• Exposed granite
• Smooth
• Textured

Some products even have factory coatings for stain resistance. These can be integral or surface applied.

Concrete slabs unit size (34:20)

Concrete slabs finish (36:40)

Face mix:

• A layer of "specialized" concrete mix representing about 12% of the total depth of the product
• Can be made up of either normal fine aggregates or a blend of high-quality minerals or aggregates

Blasted – Arcana (37:20)

Project references (37:38):

• Alta, Chicago (2017) (37:38)
• Lake & Aberdeen, Chicago (2017)
• One East Delaware, Chicago (2018)

Mottled – Umbriano (38:40)

Project references (39:13):

• 2950 N. Sheridan Road, Chicago (2017) (39:13)
• Oak Park Station, Oak Park, Il (2017)

Exposed granite – Series (39:52)

Use surface texture to provide visual interest:

• Smaller, fine aggregates perceived as soft
• Larger, chunkier aggregates appear bold and strong

Exposed granite surface reflects light without a sparkle.

Smooth or flagstone – Premier (40:58)

Color options (41:10):

• Solids appear flatter and cleaner.
• Blends tend to have more depth. (Flagstone will add more visual interest.)

Project references:

• Lake Park Plaza, Chicago (2017) (41:20)
• Outdoor seating area tiled with blended and coated Premier Smooth (41:30)

Natural stone (42:42)

Finish options (42:45)

Considerations:

• Edges
• Slip resistance
• Strength – limestone and flamed

Natural stone standards (43:18)

Color and texture options (43:31)

Example: House with sandstone material on roof deck (43:55)

Porcelain tile (44:11)

Project example (44:25)

Porcelain tile standards (44:40)

Size, texture, and color options (45:48)

Example: Bradley Business Center (46:15)

Installation variety (46:40):

• Pedestals
• Mortar set
• Dry set with sand joint

Porcelain tile standards (47:15)

Pedestal placement (47:30):

• May require additional supports
• Suggested max height of 3 inches without back panel

Wood decking (48:30)

Wood products appear inviting because of their warm colors.

Although many IPE wood products are fire rated, confirm with local building codes that they can be used.

48:57 – 54:18: Pedestal Selection

Fixed height (49:14)

Benefits and challenges:

• Uses schedule 40 PVC cut to exact heights
• Less material costs
• More labor intensive

Adjustable (49:36)

Benefits and challenges:

• Adjustable range
• Includes slope correction
• Less labor cost
• More expensive than fixed height

Manufacturers (49:56)

Elmich Paver Support VersiJack (50:06)

Bison Innovative Products (51:23)

Design and layout (52:40)

Recommended information:

• Plan of roof area with scale or dimension strings
• Plan of roof area with roof elevations or finish floor elevation (FFE)
• Plan of roof area with drain, scupper locations, and ridge lines
• Detail section showing the cavity height with FFE
• Door threshold elevations
• Specification or plan indicating materials/slab products

Unilock pedestal layout drawings (53:43)

Project reference: Prudential, Chicago (54:05)

54:19 – 57:49: Installation Concerns

Wind uplift (54:25)

Unit size/shape and layout (56:15)

57:50 – end: Vertical Elements

Seat walls and planters (57:50)

Question: What keeps the pedestal bases from shifting over time? (1:01:10)

Answer: The weight of the pedestals themselves.

Question: What percentage of slope do you use for rooftop paver surfaces? Is it different from typical ground plane? (1:01:50)

Answer: Ground plane paving is usually laid at a minimum 1 to 2 percent slope to allow for drainage. Rooftop pavers are generally laid pretty flat.

Wind uplift systems that are not temperature sensitive (1:02:53)

Question: When trying to get material to the roof, how does labor cost affect things? (1:04:15)

Answer: Ideally, a tower crane or lift should be present. When human workers have to come up through the building and can only bring up a handful of materials, have to use the service elevator, etc., that's when the costs start to increase. It depends on the labor cost of how far the workers have to wheel the paving material to get it up to the roof.