A permit is required for the installation or repair of retaining walls. If you have hired a contractor(s) to perform the work, they must obtain a Contractor's Business License with the Village before issuance of the permit.
If you have any questions, please contact the Permitting Division of the Community Development Department at 847.923.4420.
Inspections can be scheduled up to 4pm the business day prior to the requested inspection date by contacting the Permitting Division of the Community Development Department at 847.923.4420.
Concrete Block Retaining Wall Less than 3 Feet High (Preferred):
The manufacturer's recommendations should be followed whenever possible. The lowest point along the line where the retaining wall will be built must be determined.
Starting at the lowest point, dig a trench deep enough to build a stone base and at least half the height of one of the blocks. This trench should be at least 6” deep depending on the height of the wall and the size of the blocks, and approximately 18” from front to back to allow for the block plus one foot of backfill behind the wall.
The stone base is key to building a strong and long-lasting wall. Starting at the lowest point, install at least 4” of CA-6 (compactable stone) for a minimum foundation. Level stone base in both directions then compact base.
Starting at the lowest point, lay the first block and level it in both directions. Do this with the remaining blocks for the first course. Once the first course is laid out, fill in behind the wall with CA-7 (clean stone) and compact.
Start the next and succeeding courses staggering the blocks one half the width of the blocks. Each block should be centered over the seam of the two blocks in the course below. Each block should be checked for level as the work progresses. Each course of the wall should be backfilled as above with CA-7 and compacted. This process should be repeated until the body of the wall is nearly complete. After the last course is set, the wall should be backfilled with topsoil if grass or plantings are going to be placed behind the wall.
The cap course is a finishing course that hides the seems and gaps left behind after the body of the wall is complete. The cap course should be glued (special glue available at home improvement stores) to secure it to the bottom courses and to tie the wall together. The cap course should be backfilled with top soil as above.
In a wall that will likely have large amounts of water behind it, it might be a good idea to lay perforated drain tile in the CA-7 in back of a course that is above the finished grade of the wall. This will help relieve the pressure of the water behind the wall during the freeze and thaw periods of the year.
Adding a layer or two of geogrid between some of the courses will reinforce the wall and keep it from moving or falling over. A trench will need to be excavated that is at least 3’ greater from front to back than the original design of the trench.
For any wall that will have a significant length that is more than 3' above adjacent grade, a structural engineer will need to design the wall and sign and seal the plans with an Illinois structural engineer stamp. This type of wall should also be constructed by a professional contractor who specializes in this type of work.