Quick Start Guide for USA Contractors Using London Boulder Precast Concrete Blocks

Installing a LondonBoulder BIG Block system is designed to be straightforward and efficient, making it the go-to choice for many contractors. As a leader in the precast concrete industry, LondonBoulder provides superior precast concrete solutions that cater to various construction needs. With a range of block sizes and comprehensive support from our team, setting up your wall is hassle-free. Here’s a quick start guide to help you get started:

Excavation and Base Preparation

Set Wall Elevations: Before you begin excavation, use a laser level and stakes to set wall elevations. This ensures your project starts on the right foot, enhancing efficiency and accuracy.

Excavate the Foundation: Excavate the foundation soil to match the lines and grades of your construction drawings, being careful not to disturb the foundation beyond the indicated depths. For the LB42 units, excavate a base trench to a minimum of 60 inches wide and 6 inches deep. For LB28  blocks, the minimum base width would be 40. Over-excavated areas should be filled with compacted backfill material.

Prepare the Base: Use granular, inorganic materials like crushed road base material, crushed stone, or recycled concrete to prepare the base leveling pad. The base should maintain a width wider than the unit size and a minimum depth of 6 inches after compaction. The compaction should meet or exceed 95% Standard Proctor using a mechanical plate compactor. Alternatively, concrete can be used as a base material. Utilizing precast concrete products for the base can provide a solid and stable foundation, showcasing the versatility of precast concrete solutions.

Level and Compact the Base: Ensure the base is uniform, level, and well-compacted. A properly prepared base limits the number of future repairs due to sagging walls or other base-related failures.

Install Drainage: Install a drainage pipe behind the wall, which should daylight into a storm sewer manhole or a sloped area lower than the pipes behind the walls. The main collection drainpipe should be a minimum of 4 inches in diameter.

Setting the First Course

  1. Start at the Lowest Elevation: Begin the base course at the wall’s lowest elevation. For varying base elevations, refer to installation guidelines for stepping up from one course to the next.
  2. Place the First Course: Place the first course of LondonBoulder blocks directly on the leveling pad, ensuring they are properly aligned and leveled. The bottom surface of each unit should fully contact the base. This method underscores the practicality and efficiency of using blocks.
  3. Align the Blocks: Use a string line or laser level to align a straight wall. A radius string from an established center point may be helpful for convex or concave walls.
  4. Install Drainage Pipe: Place perforated or slotted PVC or corrugated HDPE pipe behind the course for optimal drainage. Surround the drain pipe with a minimum of 1 foot of drainage stone.


  1. Compact the Drainage Material: Using appropriate equipment, properly compact all drainage material in the drain field and infill soils within 3 feet of the wall.
  2. Compact in Lifts: Compact in maximum 6-inch lifts, meaning compaction should occur at least three times with each course of LondonBoulder units set.
  3. Place Drainage Aggregate: Place drainage aggregate behind and up to the height of the LondonBoulder wall. The aggregate should be at least 12 inches thick from the back of the LondonBoulder unit.

Installing Successive Courses

  1. Level the Drainage Aggregate: Ensure the drainage aggregate is level with or slightly below the top of the LondonBoulder unit.
  2. Clean the Units: Remove excess material and debris from the top of the units to prevent unevenness.
  3. Offset the Seams: Place the next row of LondonBoulder units with the seams offset from those of the units below.
  4. Engage the Lugs: For a 6-inch setback, place the lugs to engage the back edge of the units below. For 2-inch and 0-inch setbacks, the lugs should set into the channel of the unit below.
  5. Check Alignment: Set up a string line horizontally down the wall to ensure straightness. Adjust units as needed to form straight lines and smooth curves, checking each block for level.
  6. Continue Backfilling: Place drainage aggregate and infill soil as previously stated, and repeat these steps until the wall reaches its final height.

Special Notes for Precast Concrete Block Production

For Partition Walls: If installing a partition wall, follow a specific pattern with full-unit increments. The base course should consist of full and full-corner units and the second course should be encased by half-corner blocks. Repeat this pattern for subsequent rows.

For Walls Taller than 9 Feet: Consult a certified engineer for walls greater than 9 feet tall to ensure structural integrity.

Final Tips

– Use LondonBoulder’s support staff to answer any questions during installation.
– Refer to the installation literature for detailed guidance and illustrations.
– Ensure consistent communication and collaboration with your team to maintain project efficiency and accuracy.

Following these steps, you can efficiently set up a LondonBoulder BIG Block wall, ensuring a strong, reliable, and aesthetically pleasing structure. LondonBoulder provides the tools and support to make your project successful, whether for retaining or partitioning walls. Using high-quality precast concrete products ensures durability and longevity, enhancing the overall integrity of your construction. 

As a leader in the precast concrete industry, LondonBoulder is committed to providing our customers with top-tier solutions that meet the demands of challenging construction projects. Let LondonBoulder’s expertise and superior precast concrete products guide you to a flawless installation, solidifying your structure and elevating your project to new heights.

LondonBoulder – Family Owned 

At LondonBoulder, we aim to provide the best forms possible for custom precast concrete blocks. If you’re a precast concrete manufacturer looking to design and build a structure using blocks, you’re in the right place. LondonBoulder precast big blocks can produce more than just walls. Check out our case studies to see the different types of structures our forms can produce! We’re versatile, from commercial building parking structure walls to residential precast concrete structures. Whether you’re in the construction industry or specialize in architectural concrete, we have possibilities for you! If you’re a precast concrete company in the USA or Canada, give us a call today!

Precast Concrete Companies in USA or Canada – Contact Us Today!