CLA Hardscape & Materials Flashcards

What is the ADA-required minimum clear width for an accessible pedestrian path?

Answer: 36 inches

The ADA Standards for Accessible Design require a minimum 36-inch clear width for accessible routes, with 60-inch passing spaces every 200 feet on one-way paths.

What is the maximum slope allowed for an ADA-compliant ramp (running slope)?

Answer: 1:12 (8.33%)

ADA Standards allow a maximum running slope of 1:12 (8.33%) for ramps with handrails; steeper slopes are not permitted for new accessible ramp construction.

When specifying wood for outdoor decking in a humid climate, which treatment is essential for preserving structural members in ground contact?

Answer: Pressure treatment with preservatives (CA, CA-C, or similar)

Pressure-treated lumber with approved preservatives (such as CA or CA-C) is required for ground-contact applications to prevent decay and insect damage in humid conditions.

What type of fastener is preferred for stainless steel or aluminum exterior landscape structures in coastal environments?

Answer: Stainless steel (316-grade)

316-grade stainless steel fasteners are highly corrosion-resistant to salt air and moisture, making them the preferred choice for coastal landscape construction.

What is the typical joint width recommended between natural stone pavers when using a dry-laid mortar or polymeric sand installation?

Answer: 1/8 to 1/4 inch

Joints of 1/8 to 1/4 inch allow for slight movement, accommodate variations in stone size, and provide space for polymeric sand or fine mortar to lock units together.

Which pavement material is characterized by being flexible, recyclable, and requiring periodic resealing to maintain performance in parking areas?

Answer: Hot mix asphalt (HMA)

Hot mix asphalt is a flexible pavement that deflects under loads, is 100% recyclable, and requires periodic seal coating to prevent oxidation and cracking.