Retaining Walls (D07)
Retaining walls hold back earth – making them structural elements that can fail catastrophically if designed or built wrong.
This BidScope guides you through wall systems: segmental block walls (interlocking concrete blocks, most popular for residential, engineered for heights up to 30+ feet with proper design), poured concrete walls (maximum strength, required for many commercial applications, can be faced with stone or brick), boulder walls (natural appearance using large boulders, typically for shorter walls under 4 feet), timber walls (treated lumber or railroad ties, economical but limited lifespan in Utah moisture), and gabion walls (rock-filled wire baskets, good drainage, industrial aesthetic).
Learn critical height thresholds: walls over 4 feet typically require engineering in Utah, walls over 6 feet almost always require stamped engineering plans.
Understand soil pressures and loads: active pressure (soil pushing against wall), surcharge loads (slopes, buildings, traffic above wall), seismic loads in Utah’s Wasatch Fault zone.
Master drainage – the single most critical factor in retaining wall success.
Plan base preparation with proper embedment depth (typically 10% of wall height minimum).
Know reinforcement options: geogrid for taller segmental walls, rebar in concrete walls, deadmen anchors for timber walls.
Navigate permit requirements and setbacks.
Calculate quantities and costs realistically – retaining walls are expensive due to excavation, materials, drainage, and engineering.
Understand long-term durability by material type.
This tool ensures your retaining wall is properly engineered, built to last, and won’t fail when Utah weather tests it.
What’s Included:
- Retaining wall systems (segmental block, poured concrete, boulder, timber, gabion, stone)
- Segmental retaining wall blocks (interlocking, engineered, popular residential)
- SRW manufacturers (Allan Block, Versa-Lok, Keystone, Belgard)
- Poured concrete retaining walls (maximum strength, commercial grade)
- Reinforced concrete wall design
- Boulder retaining walls (natural appearance, shorter walls)
- Timber retaining walls (treated lumber, railroad ties, limited lifespan)
- Gabion walls (rock-filled baskets, drainage, industrial look)
- Height considerations and engineering requirements (4 feet+ needs engineering typically)
- Wall height and engineering stamps (6 feet+ almost always requires PE stamp)
- Soil pressure calculations (active pressure, passive pressure, at-rest)
- Lateral earth pressure and wall design
- Surcharge loads (slopes, structures, traffic above wall)
- Seismic loads and Wasatch Fault requirements
- Drainage behind walls (THE most critical success factor)
- Drainage aggregate (3/4-inch crushed rock behind wall)
- Perforated drain pipe at wall base (4-inch minimum)
- Weep holes through wall face
- Filter fabric to prevent soil migration
- Base preparation and leveling
- Embedment depth (10% of wall height minimum, 6-12 inches typical)
- Base aggregate compaction
- Wall batter (backward lean, typically 1 inch per foot of height)
- Geogrid reinforcement for taller SRW walls
- Geogrid specifications and placement
- Rebar placement in concrete walls
- Deadmen anchors for timber walls
- Caps and copings for finished appearance
- Structural backfill and compaction
- Permits and engineering requirements
- Setback requirements from property lines
- Cost factors (height, material, engineering, excavation)
- Failure modes and prevention
- Long-term durability by material
- Finding qualified wall contractors
- Engineering coordination
