Corners are often the most visible and technically sensitive part of a retaining wall when it comes to construction. When corners are planned properly and built following Allan Block best practices, they perform well in both gravity and reinforced applications. Proper base preparation, accurate layout, attention to block orientation and reinforcement placement are critical to long-term wall performance.

Inside corners are easily constructed using standard Allan Block units, but they do require block modification to allow the units to overlap and interlock correctly. The raised front lip must be partially removed to allow the course above to be installed on a flat surface, this process alternates with each course to tie the adjoining wall segments together. Allan Block best practices call for extending geogrid through the corner with an overlap equal to at least 25% of the wall height, alternating grid direction on successive courses. This added grid length helps maintain reinforcement continuity and ensures proper load transfer through the corner.

Outside corners generally require more time and precision to construct, as alignment errors can compound as the wall increases in height. Allan Block corner units are designed specifically for these conditions and should be used whenever possible. Construction should begin at the corner and work outward in both directions, alternating corner block orientation on each course to maintain proper interlock. Leveling, extra backfill, and proper compaction are especially important at outside corners, where changes in wall direction affect stability. When reinforcement is required, geogrid should be staggered and alternated down each side of the corner on every course.

For both inside and outside corners, cutting caps at 45-degree angles and securing them with a high-strength construction adhesive provides a finished appearance and helps protect the wall long term.

The AB® Collection is the cornerstone of retaining wall products. The most popular collection from Allan Block is designed to add lasting beauty and structural strength that will never go out of style.

This collection features multiple block sizes that can be used individually or blended together to create the popular AB Ashlar Blend™ patterns. That flexibility allows you to offer customers a wide range of design options while stocking a coordinated family of products that work seamlessly together. Ask your local sales rep for information on block options – Don’t know who that is? Reach out to salessupport@allanblock.com and we can help you out.

Whether your customers are building a modest raised garden wall or a significant hillside retaining structure, the AB Collection is suitable for a wide range of residential and commercial applications. With its classic lines and reliable performance, this collection delivers both functional integrity and enduring style that complements virtually any landscape design.

We have all heard the phrase “water is the number one enemy of retaining walls” and that is certainly true during the construction phase of a project. Many wall failures happen during construction mainly due to poor water management. Allan Block’s Best Practices recommends that at the end of every construction day a temporary berm is placed at the back of the excavation to act as a water routing system away from the wall, to prevent potential failure.

Any questions or assitance needed, reach out to our engineering team at 800-899-5309 x3 or engineering@allanblock.com.

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