Foundation soil shall be excavated to the lines and grades of the construction drawings and as required for base course installation. Use caution to ensure that the foundation is not disturbed beyond the indicated depths. As shown in Figure A, base trench shall be excavated to a minimum of 60“ wide and 6“ deep for the LB42 Units. Use compacted backfill material to fill over-excavated areas. It is permissible to use a layer of non-woven landscape fabric along the three sides of the trench to maintain a barrier between the surrounding foundation and the base material to be put down later.
Using granular, inorganic material such as crushed road base material, crushed stone, or recycled concrete, place the base leveling pad in the excavated trench such that it maintains a width of 60“ and a minimum depth of 6“ after compaction. Compaction should meet or exceed 95% Standard Proctor and should be achieved through the use of a mechanical plate compactor.
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Concrete may be substituted for the granular base material. Granular base material may also be top-dressed with a minimum 3“ thick layer of lean and unreinforced concrete. Reinforced footings must be placed below the frost line.
Final base must be uniform, level, and well compacted to provide the best possibility for a smooth, hassle-free wall installation. Achieving this standard in the base will also help to limit the number of future repairs that may be necessary due to sections of sagging wall and other base-related failures.
Level compacted base material from side to side and front to back.
A drainage pipe should be installed in all walls. The drainage collection pipe should daylight into a storm sewer manhole or to a sloped area lower than the pipes behind the walls. The main collection drainpipe just behind the block facing shall be a minimum of 4″ in diameter.