Install Slab Base, Vapor Barrier, and Reinforcement

A. Finished-Project Specification

Deliverable: a completed Slab Preparation Inspection Worksheet recording base elevation and compaction results, vapor-barrier product and seam-sealing verification, reinforcement size, spacing, lap, cover, and support verification, embedded-system coordination, and a formal release signature authorizing concrete placement to begin in Project 16.

B. Assessed Preparation Schedule

Item	Reference Used	Standard	Purpose
Aggregate lifts	Slab benchmark and approved base plan	Placed and compacted within the specified loose-lift thickness and compaction requirement	Establish a uniform, stable base
Fine grade	Slab benchmark	Matches required plane, thickness, slopes, and depressions	Support the vapor barrier and control slab thickness
Vapor barrier	Manufacturer instructions and approved plan	Continuous, correctly oriented, with specified edge extensions	Control vapor transmission through the slab
Seams and penetrations	Manufacturer instructions	Lapped, sealed, and boot-sealed using compatible materials	Maintain barrier continuity at joints and penetrations
Reinforcement	Approved reinforcement schedule	Correct size, spacing, laps, cover, and support elevation	Provide the specified structural reinforcement at the correct depth

C. Document and Material Takeoff

• Controlling documents: approved subgrade and aggregate elevations, base thickness, compaction requirement, vapor-barrier rating, seam-treatment system, reinforcement schedule, cover requirements, and inspection requirements, assembled before any placement begins.
• Base materials: approved aggregate placed in the lift thickness stated on the approved plan.
• Vapor-barrier materials: sheeting of the specified rating, compatible seam tape or adhesive, and penetration boots or patch components identified as compatible by the manufacturer.
• Reinforcement materials: welded wire reinforcement or rebar matching the approved schedule, chairs or bolsters at the specified spacing, and tie wire.
• Escalation contact: a named inspector or designer identified before preparation begins, for use if a subgrade or embedded-system conflict is found in Step 4.

D. Acceptance Standards

Check	Standard
Base elevation and compaction	Matches the approved plan at perimeter, center, penetrations, thickened areas, and transitions; any deficiency corrected before vapor-barrier placement
Vapor-barrier continuity	Continuous, undamaged, correctly oriented, with the specified edge extensions; every puncture, tear, or contamination repaired before reinforcement placement
Seams and penetrations	Lapped and sealed to manufacturer requirements; every pipe, conduit, sleeve, and column penetration sealed with compatible boots or patch details
Reinforcement placement	Correct size, spacing, laps, and continuity matching the approved schedule
Reinforcement support	Supported on approved chairs or bolsters at the specified elevation and stable enough to remain in position during concrete placement
Embedded-system coordination	Radiant tubing, dowels, isolation joints, control-joint assemblies, and other embeds included at this stage installed without violating reinforcement, cover, or slab details
Pre-pour condition	Assembly free of loose wire, bar cutoffs, debris, and standing water; photographed and released before concrete placement

E. Preparation — Document Review and Subgrade Inspection

1. Review required subgrade and aggregate elevations, base thickness, compaction, vapor-barrier rating, seam treatment, reinforcement schedule, cover, penetrations, embeds, and inspection requirements. Confirm the document set is complete before proceeding to Step 2.
2. Verify slab forms, underground utilities, plumbing, sleeves, and subgrade approvals. Confirm Project 14's form inspection and any underground-work inspections are on record before continuing.
3. Inspect the slab area for soft spots, settlement, mud, standing water, debris, sharp objects, and damaged penetrations. Record every condition found before continuing.
4. Correct utility-trench settlement and unsuitable areas using approved fill and compaction procedures. Obtain designer or inspector direction for any condition outside the approved plan.

F. Base Placement and Fine Grading

1. Establish base-elevation controls from the slab benchmark. Mark the required lift and finish-grade elevations before placing aggregate.
2. Place approved aggregate in uniform lifts without damaging underground work. Control placement rate and equipment routing to protect sleeves and utility lines.
3. Compact each lift using equipment suitable for the area and embedded systems. Match compactor type and pass count to the specified compaction requirement and any nearby embedded system.
4. Fine-grade the aggregate to the required plane, thickness, slopes, and depressions. Use the straightedge or laser grade rod referenced from the slab benchmark.
5. Verify elevation and compaction at perimeter, center, penetrations, thickened areas, and transitions. Record each verification point before covering it.
6. Smooth or cover sharp aggregate that could puncture the vapor barrier. Remove or bury any protruding sharp material before barrier placement.

G. Vapor-Barrier Installation

1. Place the vapor barrier in the required orientation with the specified edge extensions. Extend the barrier up the slab-edge form or foundation wall to the specified height.
2. Lap and seal seams using compatible tape, adhesive, or accessories. Meet the manufacturer's minimum lap width at every seam.
3. Seal pipe, conduit, sleeve, column, and other penetrations using approved boots or patch details. Verify each penetration is fully sealed before continuing.
4. Repair punctures, tears, contamination, and failed seams. Patch every defect found before reinforcement traffic begins.
5. Establish protected walk paths and restrict traffic on the membrane. Mark the approved routes for all remaining foot and material traffic.

H. Reinforcement Placement and Support

1. Cut, place, lap, tie, or connect welded wire reinforcement or reinforcing bars according to the approved schedule. Match every bar mark, size, spacing, and lap to the reinforcement schedule.
2. Support reinforcement on approved chairs, bolsters, or supports so it remains at the specified elevation during placement. Space supports according to the approved schedule to prevent sag.
3. Install thickened-edge reinforcement, dowels, isolation joints, control-joint assemblies, embeds, and hold-down items included at this stage. Coordinate each item's exact location with the approved plan.
4. Coordinate radiant tubing or other embedded systems without violating reinforcement, cover, or slab details. Resolve any conflict with the coordinating trade before concealment.

I. Final Verification and Pre-Pour Inspection

1. Verify reinforcement size, spacing, laps, support, cover, continuity, and stability. Walk the full reinforcement layout and correct any deficiency found.
2. Inspect vapor-barrier continuity after reinforcement installation and repair all damage. Check for punctures caused during reinforcement placement.
3. Remove loose wire, bar cutoffs, debris, and standing water. Clear the assembly before photographing it.
4. Photograph the concealed assembly and complete the pre-pour inspection record. Sign and date the release section of the Slab Preparation Inspection Worksheet.