Jumbo J Retaining Wall Block

Jumbo J Retaining Wall Block give you several choices when it comes to designing your retaining wall. These block are great for both large and small walls, straight or curved, and even allow you to make 90 degree corners if needed.

Product CodeDescriptionDimensionsSq Ft CoverageWeightQty Per Pallet
JJCGJumbo J Concrete Gray Color7″H x 15 5/8″W x 12″D.76 Sq Ft58 lbs48
JJSTJumbo J Sahara Tan Color7″H x 15 5/8″W x 12″D.76 Sq Ft58 lbs48
Product CodeDescriptionDimensionsSq Ft CoverageWeightQty Per Pallet
JJCAPCGJumbo J Cap Concrete Gray Color3 5/8″H x 7 5/8″W x 13 1/2″D.19 Sq Ft25 lbs135
JJCAPSGJumbo J Cap Sahara Tan Color3 5/8″H x 7 5/8″W x 13 1/2″D.19 Sq Ft25 lbs135

Jumbo J Installation Instructions

Plan Your Project

Before beginning construction, prepare a layout plan of the wall. Walls over 4′ tall may require the use of Geo-Grid Reinforcement depending on soil condition and use. Consult an engineer for walls over 6′ tall. Be sure to consider the draining patterns, soil conditions, surcharges and the local building codes. If you have any questions ask your local dealer or a qualified engineer.

Prepare the Foundation / Leveling Pad

A solid foundation is essential to ensure a well constructed, long lasting wall. The foundation leveling pad should be at least 24″ wide and 6″ deep and composed of a compactable stone material like #53’s. A 1″ layer of sand can also be added to the top of the #53’s base to help with leveling of the first course. The first course of block should be started 1″ below grade per 1′ of designed wall height (a 3′ tall wall would require the first course of block to be 3″ below grade).

Install the First Course

Using a hammer or saw, remove the set-back lip for the first course only and place on the leveling pad. Level the Jumbo J’s from side to side and from front to back with a carpenters level. Use a string line to insure a straight line. It is very important that the first course is installed level.

Install the Backfill

Backfill with a clean, free-draining course aggregate such as #8 crushed stone or L-Gravel at least 12″ behind the Jumbo J wall. Compact each layer as you go. Use of organic topsoil or clay type soil is not recommended for backfill. Fill in directly behind the wall for approximately 12 inches. It is important to backfill each course as it is installed and compact each layer. A drainage pipe outlet at the bottom of the wall may be required for taller walls.

Install Additional Courses

Position each additional course of Jumbo J’s on the preceding course and straddle the top block half way on top of the two lower block. This staggers the vertical joints of the wall. No mortar or interlocking pins are required. Just simply stack the Jumbo J’s and the built in set-back lip will automatically establish the required stagger. It is very important to remember to backfill each course as it is installed. Walls over 4′ tall may require the use of Geo-Grid Reinforcement depending on soil condition and use. Consult an engineer for walls over 6′ tall.


NMCA Segmental Retaining Wall Installation Guide

For more information, see the below installation guide from the National Concrete Masonry Association.