Grade a Landscape Bed for Positive Drainage

Job Overview

This chapter qualifies you to grade one residential planting bed to the elevations and drainage direction called for in the approved grading and drainage plan. The finished work product is a smooth, plantable bed surface that carries water away from structures at the approved fall, blends cleanly into walks, patios, lawns, drains, and neighboring areas, and preserves the existing grade around any established tree root flare.

You will review the grading and drainage plan and every foundation and root-flare clearance it sets, confirm utilities and lawful discharge, establish high and low reference points, mark no-fill zones at siding and building openings, remove debris and soft soil, add approved soil in controlled layers, shape the grade, maintain the approved fall away from structures, blend the bed into adjacent surfaces, protect tree root flares, remove low spots, lightly firm the soil without overcompacting it, check elevation and slope, conduct a controlled water observation where permitted, correct failed areas, and document the final elevations and drainage path.

This chapter builds directly on the readiness plan from Chapter 1, the work-area protections from Chapter 2, the tested and amended soil from Chapter 3, and the cleared area from Chapter 4. It supplies the accepted grade that Chapter 6 bed edging, Chapter 7 fabric and mulch, every planting chapter, and the irrigation and drainage chapters all depend on being correct before they conceal it.

Skills You Will Demonstrate

• LS-025 — Establish drainage direction from the approved grading and drainage plan and from verified reference points.
• LS-026 — Shape soil grades in controlled layers to a smooth, uniform plane without abrupt humps or depressions.
• LS-027 — Remove low spots that would hold irrigation or rainwater within the project area.
• LS-028 — Prevent water from being directed against foundations, siding, or building openings.
• LS-029 — Compact soil lightly only where required to reduce settlement, without overcompacting planting soil.
• LS-030 — Inspect the finished bed slope using a level, laser, stringline, or approved method, and correct failed areas.

Where This Skill Fits

Grading is the point in the project sequence where the site-to-establishment order in the Book-Level Authoring Rule becomes irreversible if skipped: positive drainage must be established before edging, fabric, mulch, planting, turf, or irrigation are allowed to conceal a grading defect. The elevations set in this chapter are the reference every later chapter is required to use rather than re-derive.

This chapter uses the site plan, drainage findings, and low points recorded in Chapter 1, works inside the protected staging and equipment routes established in Chapter 2, grades soil that has already been sampled and amended in Chapter 3, and works in an area already cleared of unwanted vegetation and debris in Chapter 4. It hands off an accepted, drainage-verified bed surface to Chapter 6 bed layout and edging, and its elevations control the below-grade work assigned later to the drainage chapter and the irrigation chapters.

Scope and Intended Use

This chapter covers:

• reviewing the grading and drainage plan, foundation clearances, hardscape elevations, drains, plant depths, mulch, and settlement allowance
• confirming utilities, property limits, and lawful discharge before grading begins
• establishing high and low reference points and marking no-fill zones at siding, weeps, vents, thresholds, window wells, and wood framing
• removing debris and soft or organic soil pockets before adding soil
• adding approved topsoil or planting soil in controlled layers and shaping broad, smooth grades
• maintaining the approved fall away from structures and blending the bed into walks, patios, lawns, drains, and neighboring areas
• preserving tree root flares and existing root-zone grades
• removing local low spots and lightly firming soil only as required to reduce settlement
• checking elevation and slope, conducting a controlled water observation where permitted, correcting failed areas, and documenting the final elevations and drainage path

This chapter does not authorize the learner to:

• grade an area that has not received an approved or conditional readiness decision under Chapter 1, or that has not completed the utility locating, vegetation removal, and soil work assigned to Chapters 2 through 4
• direct runoff toward foundations, entrances, neighboring property, sidewalks, roads, public hazards, or a prohibited discharge point
• bury siding, masonry weeps, foundation vents, door thresholds, window wells, wood framing, utility markers, shutoffs, cleanouts, or inspection zones under added soil
• pile soil against trunks, alter grade over an established root flare, or compact soil over roots without qualified review
• proceed past an unidentified utility, unstable slope, contaminated soil, buried tank, sewage, major erosion, foundation conflict, groundwater, hazardous material, or unknown drainage outlet
• install edging, fabric, mulch, plants, turf, or irrigation over a grade that has not passed the inspection required by this chapter

Any area that fails this chapter's inspection must be corrected, or referred to a qualified drainage contractor, landscape architect, or surveyor where the conditions require it, and reinspected before Chapter 6 begins.