Technical Resource Guide_WEB_BEL25-D-516650 - Page 13 of 84

13 | belgard ® product installation guide | belgard.com | 877-235-4273 EXCAVATION / SUBGRADE Make sure that the area to be excavated is at least 12 in. wider than the limits of the pavers. This provides a firm base to support the edge of the pavement and the edge restraint. Make sure that the depth to be excavated is measured from finished pavement surface elevations and is marked on all grade stakes. The bottom of excavations, below finished pavement elevation, should equal the total thickness of the designed base, sand bed (after paver installation and compaction) and the paver being used. Try not to disturb the subgrade below the planned excavation depth. Over excavation is costly and can cause future problems. When all excavation is completed, compact the subgrade with a vibratory plate compactor. Make sure that compaction is thorough, uniform and complete. If soft spots are encountered, they should be removed and backfilled with the material to be used for the base. If the subgrade is too wet to compact, allow it to dry or try adding a few inches of dry base material before compacting. EXAMPLE: Base (compacted) 6-in Sand bedding 1-in Paver thickness 23/8-in Total Depth 93/8-in BASE The dense graded aggregate base material should be spread in layers of uniform thickness then compacted. The thickness of the layer depends on the method of compaction and the planned use of the pavement. While compaction of the subgrade and base layers is key to the performance of any pavement. Place the base in two or three lifts for most residential installations. Compact the base material with a reversible plate compactor of at least 7,000 lbf or a vibratory roller. Place and compact the base material as recommended, making sure to keep the material lightly dampened. If free water appears on the base surface during compaction, the material is too wet and should be allowed to dry. Be sure to thoroughly compact along edges, in corners and around structures. These are the most difficult areas to treat and the most apt to cause future settlement problems. Do not use frozen base material and do not place base material over a frozen subgrade. When proper compaction of the base has been achieved, the surface should be smooth, leave no areas into which the bedding sand can migrate. It may be necessary to fill any such areas with a finer material then recompact. The finished base surface should be flat (no more than 3/8 in. plus or minus variation under a 10 ft. straight edge) and uniformly true to grade. 1-inch sand bed Edge restraint Minimum of 12" Base Spike Geotextile Subgrade