Prepare the Subgrade

1. Excavate to depth allowing space for TRUEGRID® paver thickness and base depth specified by a commercial install’s site Engineer or TRUEGRID® typicals for common construction practices. Grid must be ¼” or slightly below surrounding grade or edging. TRUEGRID® cross sections can be built above existing grade without excavation. However, proper edging to keep base aggregate encased is recommended.
2. Subgrade must be relatively dry. No standing water. Proof roll subgrade or stabilize subgrade when necessary for unstable soils.
3. Lay a geofabric (if specified).  Geofabric recommended for separation between subgrade soils and detention base stone to prevent interblending and loss of detention void space in detention base stone.
4. Subgrade soils with poor permeability require drainage. Slope the subgrade for sheet flow, install perforated pipe or drain with outlet as specified by site Engineer to move water and drain the site. (refer to TRUEGRID® typicals for engineering direction). Link.

Prepare the Base

1. Lay base rock. Clean, angular stone ¾” to 1”. (#57 common) Compact in 4” lifts with a heavy compactor (heavier the better) to settle, level and lock in clean angular stone. DO NOT USE ROUND ROCK.  When detention or subsurface drainage is not needed, a typical compactible road base can be used.
2. Do a final heavy compaction. Level with chalk line or laser leveler.  A final plate compaction to subbase stone will provide an even surface for the TRUEGRID® Paver to be directly installed on.

Install TRUEGRID Pavers

1. Grid must be ¼” or slightly below surrounding grade, adjoining edging, or transition pavement.
2. Start in corner of site with male tabs on grid facing out.  Line up grid and connect next grid section. Install SuperSpots. (see common SuperSpot layout details) link.

TRUEGRID can be cut to form or around trees, curbs and any organic shape. Cut with electric saw such as a circular saw or reciprocating saw.

Fill Grid with Gravel

1. Fill grid with 5/8” or ¾” fill rock. Spread to top of grid cells or slight overfill as desired. Compact to settle and lock in infill aggregate.