Landscape Design Hardscape Design 2 — Questions and Answers
Question 1: What does ADA compliance require for exterior walkway slopes accessible to people with disabilities?
- Maximum 10% running slope and 3% cross slope
- Maximum 8.33% running slope (1:12) and 2% cross slope (Correct answer)
- Maximum 5% running slope and 5% cross slope
- Maximum 15% running slope with handrails
Correct answer: Maximum 8.33% running slope (1:12) and 2% cross slope
ADA Standards require accessible routes to have a maximum running slope of 8.33% (1:12 ratio) and a maximum cross slope of 2% to accommodate wheelchairs and mobility devices.
Question 2: Which type of concrete paver pattern is known for its superior interlocking strength and is commonly used for driveways?
- Running bond
- Stack bond
- Herringbone (45° or 90°) (Correct answer)
- Basketweave
Correct answer: Herringbone (45° or 90°)
The herringbone pattern creates superior interlock between pavers, distributing loads more effectively and resisting lateral movement, making it ideal for driveways and high-traffic areas.
Question 3: What is 'efflorescence' on masonry or concrete surfaces?
- A decorative stain applied to concrete for color
- White salt deposits that migrate to the surface as water moves through masonry (Correct answer)
- Moss and algae growth on shaded hardscape
- The weathering pattern that appears on aged limestone
Correct answer: White salt deposits that migrate to the surface as water moves through masonry
Efflorescence is the white, chalky deposit left on masonry and concrete surfaces when water carries soluble salts to the surface and evaporates, leaving the salts behind.
Question 4: What is the 'rise and run' formula for designing comfortable outdoor steps?
- Rise + Run = 24 inches (2R + T = 24–26 inches) (Correct answer)
- Rise × Run = 144 square inches
- Rise = Run × 2 for all outdoor applications
- Rise must equal Run for safe outdoor steps
Correct answer: Rise + Run = 24 inches (2R + T = 24–26 inches)
The standard formula for comfortable outdoor steps is 2 × Rise + Tread (Run) = 24–26 inches, with typical outdoor steps having a 6-inch rise and 12–15-inch tread.
Question 5: What is a 'French drain' in landscape hardscape design?
- A decorative stone channel used in formal European garden styles
- A subsurface drainage system using a perforated pipe in a gravel-filled trench to redirect groundwater (Correct answer)
- A type of drainage grate installed in patio surfaces
- A raised concrete curb used to direct surface runoff
Correct answer: A subsurface drainage system using a perforated pipe in a gravel-filled trench to redirect groundwater
A French drain is a subsurface drainage solution consisting of a perforated pipe surrounded by gravel in a trench, designed to collect and redirect groundwater away from problem areas.
Question 6: Which factor is most critical when selecting the thickness of concrete for a residential driveway?
- Aesthetic preference of the homeowner
- Anticipated vehicle loads and soil bearing capacity (Correct answer)
- Local building codes only
- The color of the aggregate selected
Correct answer: Anticipated vehicle loads and soil bearing capacity
Concrete thickness for driveways must be designed around anticipated vehicle loads and the bearing capacity of the subgrade soil, with typical residential driveways requiring 4 inches minimum.
Landscape Design Hardscape Design 2
What does ADA compliance require for exterior walkway slopes accessible to people with disabilities?