Understand Mortarless Wall Design and Drainage

What happens here

It is crucial to understand that interlocking retaining walls are intentionally designed to be mortarless. Mortaring these walls, as shown in an example of a failing wall, prevents proper water drainage. Water trapped behind a mortared wall will exert hydrostatic pressure, leading to wall failure, especially during freeze-thaw cycles where the expanding ice pushes the blocks out. Mortarless construction, combined with a proper drainage zone (e.g., 3/4 clear gravel) and geogrid, allows water to flow freely through the gaps between blocks and weep out evenly, preventing pressure buildup and ensuring the wall's longevity.