Build a Concrete Slab Building Pad

Job Overview

This project qualifies you to prepare the earthwork and aggregate building pad for a future concrete slab, using the slab dimensions, finished-floor elevation, base thickness, subgrade requirement, drainage, and inspection criteria supplied by the approved plan. The finished work product is a compacted, fine-graded slab building pad ready for foundation and concrete work. This project does not include placing reinforcement, forms, vapor barrier, or concrete; it ends with the pad prepared and inspected for those following operations.

You will review slab dimensions and finished-floor elevation; verify underground utility and plumbing work is complete or coordinated; re-establish the slab perimeter, control lines, and benchmark; inspect the pad for unsuitable soil, trenches, soft spots, organic material, and standing water; correct utility-trench settlement and disturbed areas; cut or fill the pad to the required subgrade elevation; compact fill in controlled lifts; establish and place the aggregate base; fine-grade the base to the required plane and thickness; verify elevations and slopes; protect embedded work; and prepare the pad for the vapor barrier, reinforcement, forms, and inspection that follow in later work.

This is the eleventh project in the site preparation sequence. It follows the rough grade shaped and protected in Project 10, which must remain at its verified elevation and undisturbed until this project begins. The compacted, fine-graded pad established here supports the vapor barrier of Project 7 where included in scope, and the foundation backfill and drainage work of Projects 12 through 14 that follow around the completed foundation.

Skills You Will Demonstrate

• SP-061 — Review slab dimensions, finished-floor elevation, base thickness, subgrade requirement, drainage, and inspection criteria, and verify underground utility and plumbing work is complete or coordinated before pad preparation begins.
• SP-062 — Re-establish the slab perimeter, control lines, and benchmark, and inspect the pad for unsuitable soil, trenches, soft spots, organic material, and standing water.
• SP-063 — Correct utility-trench settlement and disturbed areas using approved fill and compaction, and cut or fill the pad to the required subgrade elevation.
• SP-064 — Compact fill in controlled lifts and document tests, establish aggregate-base elevation, and place approved aggregate in uniform lifts.
• SP-065 — Compact aggregate without disturbing embedded work, fine-grade the base to the required plane and thickness, and verify perimeter and interior elevations and required slopes.
• SP-066 — Check for loose material, sharp objects, rutting, pumping, and contamination; correct failed elevation, compaction, or surface conditions; protect plumbing, conduit, sleeves, and penetrations; and complete the slab-base pre-inspection.

Where This Skill Fits

Project 10 shaped and protected the rough grade this project refines to slab-pad tolerance; a rough elevation, drainage shape, or compaction condition left uncorrected from Project 10 is a prerequisite deficiency for this project, not a condition to grade around. Project 6 established the compaction discipline this project applies at slab-pad precision, and Project 9 established the utility trenches whose settlement must be checked and corrected before this pad is finished.

The compacted, fine-graded pad established here remains in place, protected from traffic, weather, and disturbance, until the vapor barrier, reinforcement, forms, and concrete placement that follow. Do not proceed to reinforcement or concrete work while a required elevation, compaction condition, or embedded-work protection established in this project remains uncorrected.

Scope and Intended Use

This project covers:

• reviewing slab dimensions, finished-floor elevation, base thickness, subgrade requirement, drainage, and inspection criteria
• verifying underground utility and plumbing work is complete or coordinated before pad preparation begins
• re-establishing the slab perimeter, control lines, and benchmark
• inspecting the pad for unsuitable soil, trenches, soft spots, organic material, and standing water
• correcting utility-trench settlement and disturbed areas using approved fill and compaction
• cutting or filling the pad to the required subgrade elevation
• compacting fill in controlled lifts and documenting tests
• establishing aggregate-base elevation and placing approved aggregate in uniform lifts
• compacting aggregate without disturbing embedded work
• fine-grading the base to the required plane and thickness
• verifying perimeter and interior elevations and required slopes
• checking for loose material, sharp objects, rutting, pumping, and contamination
• correcting failed elevation, compaction, or surface conditions
• protecting plumbing, conduit, sleeves, and penetrations
• preparing access for vapor barrier, reinforcement, forms, and inspection, recording final dimensions, elevations, compaction results, and penetrations, and completing the slab-base pre-inspection

This project does not authorize the learner to:

• begin pad preparation before underground utility and plumbing work is confirmed complete or coordinated for this stage
• place fill or aggregate over an unresolved trench settlement, soft spot, or unsuitable material
• select a subgrade elevation, base thickness, or drainage slope that differs from the approved plan without first obtaining direction
• compact aggregate in a manner that disturbs, crushes, or displaces embedded plumbing, conduit, sleeves, or penetrations
• place reinforcement, forms, vapor barrier, or concrete as part of this project
• release the pad for the next operation without completing the slab-base pre-inspection

Any condition requiring a revised elevation, a different fill or aggregate source, an engineer's determination, or a decision outside the approved plan must be escalated before work proceeds in that area.