Does a boulder wall need drainage?
Due to the weight and shape of the rocks, no mortar is required when constructing a sturdy wall. A major advantage of boulder retaining walls is that they offer natural drainage. When residential retaining walls fail, it is most often due to poor drainage.
Why do boulder retaining walls fail?
The strength of a boulder retaining wall and its overall holding capacity comes from the sheer weight of the boulders being used. Small stones simply can’t hold back big banks. The second misapplication when building a boulder retaining wall is using a large boulder, but using it in the wrong way.
How do you tell if a retaining wall is failing?
The three most common signs of a retaining wall in distress are (1) Leaning; 2) Cracking and 3) Bulging of the Wall or Segments. These are telltale indicators of a wall losing its fight and at risk of collapsing at any moment, including the worst possible moment: the middle of a rainstorm.
How much does a boulder wall cost?
For boulder walls, expect to pay a minimum of $20 to $55 per face foot (one square foot of the face of the wall) for labor and materials, as locally sourced boulders require time and expense to move. Most boulder walls aren’t more than two rows high.
Should you use landscape fabric behind retaining wall?
Landscape fabric is thin and sturdy and is a simple way to preserve a retaining wall’s construction. Dig a 6- to 8-inch wide trench immediately behind the retaining wall with a shovel. Dig slowly and carefully to avoid putting added pressure on the wall and causing it to topple over. Backfill the trench will gravel.
How long do boulder retaining walls last?
between 50 to 100 years
A solid natural or cut stone retaining wall will last between 50 to 100 years. It is easy to erect a stone retaining wall using a dry-stack method, without the need for mortar to hold it together.
What do you use for drainage behind a retaining wall?
Gravel Backfill For proper drainage, the first 12 inches of space behind a retaining wall should be filled with crushed stone or gravel. This is so that when water gets into the space, it does not become bogged down in soil but instead can flow down the wall to the drains or weep holes.