Screed Bedding Sand for Paver Installation

A. Finished Work Specification

Deliverable: one screeded bedding-sand section over an accepted aggregate base, installed using screed rails set to the approved elevation and slope, struck to a uniform surface, with rail voids filled flush, free of ridges, hollows, contamination, footprints, and disturbed areas, and covered with pavers before the approved exposure window expires.

B. Bedding Work Record Schedule

Record	Required Content	Source
Base confirmation	Acceptance date, elevation, slope, cleanliness, and dryness at time of screeding	Chapter 5 acceptance record and reconfirmation
Rail placement	Rail elevation, support method, slope check, and parallel alignment check	Field measurement
Bedding placement	Material source, gradation, moisture condition, and placement method	Field inspection
Screeding	Screed-board method, low-area fill, high-area removal	Field work
Rail-void repair	Fill material, strike-off method, and confirmation no overcompaction occurred	Field inspection
Surface protection	Method used to prevent traffic, wheeled equipment, or stockpiling on the screeded area	Field observation
Thickness and surface check	Spot-check thickness results and surface condition findings	Field measurement
Coverage	Time and date screeded areas were covered with pavers or protective covering	Field record

C. Acceptance Standards

Check	Standard
Base confirmation	The base is accepted under Chapter 5, dry enough to screed, clean, and undisturbed immediately before rail placement
Rail elevation and slope	Screed rails are set to the bedding elevation calculated from the accepted base elevation plus the approved bedding thickness, with slope matching the accepted base slope and rails parallel within the stated tolerance
Bedding material	Sand is free of visible contamination, segregation, freezing, or saturation at the time of placement
Screeded surface	The struck surface is free of ridges, hollows, footprints, wheel tracks, and stockpile marks across the full screeded area
Rail-void repair	Rail voids are filled with matching bedding material and struck flush without overcompacting the surrounding bedding
Thickness	Spot-check measurements confirm the approved compacted or loose thickness across the screeded area
Surface protection	No footprint, wheel track, or stockpile mark is present on the screeded surface at the time of paver coverage
Coverage timing	Every screeded area is covered with pavers or an approved protective covering within the approved exposure window

D. Preparation — Review and Base Confirmation

1. Review bedding material, compacted or loose thickness, screed-rail method, base elevation, slope, and work sequence. Confirm every value against the approved bedding-material specification and the Chapter 5 acceptance record before staging equipment.
2. Confirm the base is accepted, dry enough, clean, and undisturbed. Reinspect the base surface immediately before rail placement, even if acceptance occurred on an earlier work day, and record the reconfirmation.
3. Verify that drains, edges, borders, and fixed elevations are coordinated. Compare the marked locations of these features against the bedding elevation and correct any conflict before proceeding.

E. Screed-Rail Placement

1. Set screed rails or pipes to the required bedding elevation. Calculate the rail elevation from the accepted base elevation plus the approved bedding thickness, and set each rail to that elevation.
2. Support rails on the compacted base without creating soft spots. Use stable shim or support material where the base surface requires it, and avoid concentrating rail weight on a single small contact point.
3. Check rail slope and parallel alignment. Use a line level or laser level to confirm the rail slope matches the accepted base slope and that rails remain parallel across the full screeded width.

F. Placing Bedding Sand

1. Place bedding sand between and ahead of rails. Distribute sand in a controlled quantity that stays slightly above the final rail elevation, ready for the screed board.
2. Avoid segregated, contaminated, frozen, or saturated sand. Reject any delivered or stockpiled material that shows visible segregation, contamination, ice, or excess moisture, and do not place it in the screeded area.

G. Screeding the Surface

1. Pull the screed board along the rails using a controlled motion. Maintain a steady forward and slight side-to-side motion that strikes excess sand without gouging the surface.
2. Maintain continuous contact with both rails. Keep the screed board seated on both rails throughout the pull to preserve the set elevation and slope.
3. Fill low areas and rescreed. Add sand to any hollow left after the first pass and repeat the screed-board pull over that section.
4. Remove excess material from high areas. Clear surplus sand ahead of the screed board rather than allowing it to build into a ridge.

H. Rail Removal and Void Repair

1. Remove rails carefully. Lift each rail vertically or slide it out along its length without dragging it across the finished screeded surface.
2. Fill rail voids with matching bedding material. Place the same bedding sand used in the screeded section into the channel left by the removed rail.
3. Strike rail voids flush without overcompacting the bedding. Level the void fill flush with the surrounding screeded surface using a hand tool, avoiding any tamping that compresses the bedding below the surrounding elevation.

I. Protecting and Covering the Screeded Surface

1. Do not walk, kneel, wheel, or stockpile material on screeded bedding. Approach every screeded section only from an unscreeded area or from pavers already installed, for the remainder of this chapter and throughout Chapter 7.
2. Cover screeded areas promptly with pavers. Begin paver placement on each screeded section as soon as practical, and do not leave a screeded surface exposed beyond the approved exposure window without an approved protective covering.

J. Inspection and Correction

1. Check bedding thickness and surface using approved spot methods. Take spot-check measurements at representative locations across the screeded area and record the results.
2. Inspect for ridges, hollows, contamination, footprints, and disturbed areas. Visually and physically check the full screeded surface before covering it with pavers.
3. Rescreed any damaged section completely. Remove and rescreed the full affected section rather than patching a footprint, wheel track, or hollow in place.
4. Document area and acceptance. Record the final inspection result, spot-check measurements, and acceptance on the bedding work record before beginning Chapter 7.