CSLB General Building (B) — All Questions

Finished grade around a building should slope away from the foundation at approximately what minimum for the first several feet?

• a.Flat, with no slope
• b.About 5 percent (roughly 6 inches of fall over 10 feet)✓
• c.Sloping toward the building
• d.A 45-degree drop

A common standard is to slope soil away from a foundation about 6 inches over the first 10 feet, roughly a 5 percent grade, to carry surface water away from the structure. Sloping toward the building or leaving it flat allows water to pond against the foundation. Positive drainage protects the structure from moisture damage.

A French drain is BEST described as what?

• a.A surface concrete channel
• b.A raised planter box
• c.A type of retaining wall
• d.A gravel-filled trench with a perforated pipe that collects and redirects subsurface water✓

A French drain is a trench filled with gravel around a perforated pipe that intercepts subsurface and surface water and carries it to a discharge point. Water enters the pipe through the perforations and flows by gravity away from the problem area. It is used to relieve soggy soils and protect foundations.

Before placing concrete pavers on a driveway, a compacted aggregate base is installed mainly to do what?

• a.Provide a stable, load-bearing, well-draining foundation✓
• b.Add color to the surface
• c.Replace the need for edge restraints
• d.Serve as the final wearing surface

A compacted crushed-aggregate base spreads loads, resists settling, and drains water away from the pavers, forming the structural foundation of the pavement. Without proper base compaction, pavers rut and settle unevenly. A sand setting bed and edge restraints are added on top of this base.

Aggregate base under hardscape is best compacted in what manner?

• a.In one thick lift with no compaction
• b.Only after the pavers are placed
• c.In thin lifts (layers), each compacted before the next✓
• d.By soaking it with water only

Base material should be placed and compacted in thin lifts, commonly around 3 to 4 inches, so the compactor can achieve full density throughout. Compacting one thick lift leaves the lower portion loose, causing later settlement. Layered compaction produces a stable, uniform base.

A segmental retaining wall over a certain height typically requires what to prevent failure?

• a.No drainage at all
• b.Engineered design, proper drainage behind the wall, and often geogrid reinforcement✓
• c.A smooth clay backfill packed tight
• d.Only decorative facing

Taller retaining walls carry large lateral soil loads and usually require engineered design, gravel backfill with a drain to relieve water pressure, and geogrid soil reinforcement. Without drainage, water pressure builds behind the wall and pushes it over. Many jurisdictions require permits and engineering above a set height, commonly 3 to 4 feet.

Weep holes or a drainage system behind a retaining wall serve what purpose?

• a.To hold more water behind the wall
• b.To add decorative accents
• c.To increase soil pressure
• d.To relieve hydrostatic pressure by letting water escape✓

Weep holes and gravel drains allow water that collects behind a wall to drain out, relieving hydrostatic pressure that would otherwise push the wall over. Saturated soil greatly increases the load on a wall. Proper drainage is one of the most important factors in wall longevity.

A slope is described as 4:1. What does this mean?

• a.4 feet of horizontal run for every 1 foot of vertical rise✓
• b.4 feet of rise for every 1 foot of run
• c.A 40 percent grade
• d.A vertical cliff

A 4:1 slope means 4 units of horizontal distance for every 1 unit of vertical change, a gentle 25 percent grade. The first number is run and the second is rise in this common landscaping convention. Flatter ratios like 4:1 are more stable and easier to mow than steep ones like 2:1.

Managing stormwater runoff on a site with a bioswale accomplishes what?

• a.Concentrates runoff into a single fast channel
• b.Prevents any water from infiltrating
• c.Slows runoff, filters pollutants, and promotes infiltration✓
• d.Raises the water table intentionally

A bioswale is a shallow, vegetated channel that slows stormwater, filters out sediment and pollutants, and encourages water to soak into the ground. This reduces peak runoff and improves water quality leaving the site. Such low-impact designs are increasingly required for stormwater management.

A concrete slab for a patio typically includes control joints. What is their function?

• a.To add decorative color
• b.To create planned weak points so cracking occurs in straight, controlled lines✓
• c.To increase the slab's water content
• d.To eliminate the need for a base

Control joints are grooved or cut lines that create a deliberate weak plane, so as concrete shrinks and cracks, the cracks form neatly along the joint rather than randomly across the slab. They are usually spaced in feet roughly equal to two to three times the slab thickness in inches. They control, not eliminate, cracking.

Edge restraints installed around a paver patio serve what main purpose?

• a.To provide seating
• b.To change the paver color
• c.To replace the gravel base
• d.To keep pavers from shifting and spreading outward over time✓

Edge restraints lock the perimeter pavers in place so the field of pavers cannot creep or spread apart under traffic. Without them, edges migrate and joints open up, leading to failure. They are a small but essential part of a durable paver installation.

A paved surface should be sloped for drainage at about what minimum cross slope?

• a.About 1 to 2 percent✓
• b.0 percent (dead level)
• c.10 to 15 percent
• d.Sloped toward the house

Paved surfaces such as patios and walkways are typically sloped about 1 to 2 percent, roughly 1/8 to 1/4 inch per foot, to shed water without being noticeably tilted. A dead-level surface ponds water, while too steep a slope is uncomfortable and unsafe. Water should always be directed away from structures.

A catch basin connected to underground drain pipe is used to do what?

• a.Store irrigation water for reuse
• b.Support a retaining wall
• c.Collect surface water at a low point and carry it away through pipe✓
• d.Filter drinking water

A catch basin is a boxed inlet set at a low point that collects surface runoff and channels it into buried drain pipe leading to a safe discharge. A grate on top keeps out leaves and debris. It is a key part of a yard drainage system that prevents ponding.

When laying out a site from a plan, a builder's level or laser level is used primarily to establish what?

• a.Soil pH
• b.Consistent elevations and grades across the site✓
• c.Plant spacing
• d.Water pressure

A builder's level, transit, or rotary laser establishes accurate reference elevations so grades, slopes, and drainage can be set consistently across a site. This ensures the finished landscape drains correctly and matches the plan. Accurate layout prevents costly grading errors.

Compaction of subgrade soil before hardscape is measured against what standard reference?

• a.The color of the soil
• b.The soil's pH
• c.The number of passes only
• d.A percentage of maximum dry density (for example, 90 to 95 percent)✓

Compaction is specified as a percentage of a soil's maximum dry density determined by a laboratory Proctor test, commonly 90 to 95 percent for hardscape subgrade. Field testing verifies the soil reaches the required density. Adequate compaction prevents future settlement under pavement.

On expansive clay soils, hardscape and foundations are at risk because the soil does what?

• a.Swells when wet and shrinks when dry, causing movement✓
• b.Stays perfectly stable in all conditions
• c.Never holds water
• d.Turns to sand over time

Expansive clays contain minerals that absorb water and swell, then shrink as they dry, producing repeated ground movement that cracks slabs and walls. Managing moisture and using proper base and drainage details reduces this movement. Severe cases may need engineered foundations.

A dry-stack (mortarless) segmental block wall relies on what for stability?

• a.Mortar between every block
• b.A concrete cap only
• c.Block interlock, setback batter, gravel backfill, and often geogrid✓
• d.Steel beams only

Mortarless segmental walls gain stability from the interlocking block design, a slight backward lean (batter or setback), free-draining gravel backfill, and geogrid reinforcement layers in taller walls. There is no mortar, so drainage and reinforcement carry the loads. Proper base preparation is also critical.

Directing a downspout's discharge onto a splash block or into a pipe that carries it away from the house prevents what?

• a.Higher soil pH
• b.Foundation soil erosion and water ponding against the structure✓
• c.Faster plant growth
• d.Better paver interlock

Concentrated roof runoff from a downspout can erode soil and saturate the ground against a foundation, leading to settlement and moisture intrusion. A splash block or piped extension moves that water away from the structure. This is a basic but important part of site drainage design.

Permeable pavers differ from standard pavers because they do what?

• a.Block all water from passing
• b.Require no base at all
• c.Are only decorative
• d.Allow stormwater to infiltrate through the joints into the base and soil below✓

Permeable pavers are set with open, aggregate-filled joints over an open-graded stone base so rainwater infiltrates rather than running off. This reduces runoff volume and helps recharge groundwater, supporting stormwater regulations. They require a specially designed base to store and drain the water.

On a steep planted slope, which practice BEST controls erosion during establishment?

• a.Erosion-control blankets, mulch, and quick-establishing groundcover✓
• b.Bare soil left exposed
• c.Smooth compaction with no plants
• d.Frequent heavy flood irrigation

Covering a slope with erosion-control blankets or netting, mulch, and fast-establishing groundcover protects the soil surface from rain impact and runoff until roots hold it. Bare or heavily flooded slopes erode and rill quickly. Vegetation and surface protection together stabilize the slope.

A retaining wall's footing or leveling pad should be placed on what?

• a.Loose topsoil
• b.A layer of dry leaves
• c.Compacted, level base material at proper depth✓
• d.A single row of bricks

The base or leveling pad of a retaining wall must rest on compacted, level base material set at the correct depth so the wall does not settle or lean. A poor base is a leading cause of wall failure. Getting the first course level and solid is essential for the whole wall.