07-01-04 | News

Tumbled Walls & Water Features

By Alan Starling, Pavestone Company

Unlike many traditional retaining wall block systems, right angle corners are easily constructed due to the rectangular form. If any steep toe or crest slopes are present, or if the walls are terraced, global stability should be accounted for.

 

Landscape contractors and ambitious do-it-yourselfers alike are discovering the natural beauty, versatility and ease of construction that tumbled walls offer. Capturing that old world charm, Pavestone Company’s tumbled wall brings a natural appeal to the segmental industry.

Utilizing a rectangular shape format, simplicity and functionalism are combined. Dry stacked or mortar set, it is easily constructed and lends itself to a wide range of design options. Tumbled wall is produced in a variety of warm earth tone colors that beautifully complements heritage pavers.

It is important to follow the correct line and grade when constructing water features to ensure that water moves properly and is contained. Proper liners must be used behind the stones as SRWs are permeable systems that will allow water to escape through the units.

As people discover the joys and pleasures of beautiful landscape designs, tumbled walls become a natural “fit” with their renewed focus on extending entertaining and living areas outside. Any segmental wall system can tame small changes in grade, but once outside of standard retaining wall function, using tumbled walls really makes a project shine. Even better, many non-traditional structures can be incorporated directly into the walls without overpowering the landscape. Cozy bench seating can be built into the walls minimizing space requirements while decreasing the opportunity of site furnishing theft. Graceful columns can be incorporated into the walls, or function as separate freestanding light columns or entry gates. Planter boxes can extend out from retaining walls, providing a pocket for greenery and colorful flowering plants. Planter boxes can also be designed as stand alone structures. Vertical parapets and free standing walls are no challenge to tumbled wall stone, and can be used as screens to obscure compost piles, pumps or utilities.

Installation of tumbled wall is similar to other segmental systems with a few exceptions. The wall stones are installed on a granular leveling pad and some portion of the wall should be embedded below finished grade. Twelve inches of drain rock should be placed directly behind the stones and be topped by a minimum 12-inch low permeable clay cap. Drain tiles should be placed at appropriate locations behind the wall. Proper drainage is especially crucial wherever irrigation or raised plantings are concerned. The tumbled wall stones are available in two sizes; a 4-inch high x 16-inch wide x 8-inch deep rectangular stone, and a 4-inch high x 8-inch wide x 8-inch deep square stone. Designers have two choices: use only the rectangular stone, or modulate it with the square one.

The stones are ideal as enclosures for outdoor grills, light fixtures or speaker systems. They can be arranged in multiple patterns with stones installed vertically as jumpers, or flat side out.

Shorter walls can be dry stacked and, if batter is required, it can be determined by a string line. Taller walls, columns and enclosures should be constructed using a good quality concrete adhesive. Taller free standing walls should be designed by professional engineers since structural columns, grade beams and piers may have to be part of the design to resist overturning and meet code for wind load. Always consult a qualified retaining wall engineer whenever local building codes require it, or when the walls exceed four feet, support a structure or a live load, or may be impacted by wind loads.

Water and Design

Water features complement outdoor living areas. They add a natural element that people are yearning for, and designers love them because of the increased creativity they inspire. Just imagine tranquil flowing water, brightly colored koi swimming lazily through clear pools, butterflies and dragonflies flitting about vividly colored water lilies and irises that contrast with lush greenery and ferns. It is easy to see why water features are such a hot commodity. The versatility of segmental retaining walls (SRWs) offers the landscape contractor the perfect vehicle to economically build these projects. Available in a wide variety of facing textures, shapes and colors, SRWs blend well with the natural beauty of the landscaping. The multi-piece Anchor Highland Stone, available in blended colors, is a good choice for water feature applications. Proper construction practices would include taking measures to avoid scour and erosion behind the walls, especially in areas of cascading or flowing water. With their tumbled appearance, they perfectly complement both concrete paving stones and natural stone while providing consistently sized shapes to facilitate construction of ponds, waterfalls, faux streams and fountains. By virtue of being relatively inert, concrete SRWs are environmentally friendly and will not introduce toxic chemicals into the environment or break down and decay over time.

Commercial Water Applications

Across the country design professionals, municipalities, departments of transportation and the Corps of Engineers are realizing the aesthetics, practicality and economics of SRWs in water applications. Used in storm water retention and detention ponds, as hard edging of lakes or ponds, as channel linings and bulkheads to prevent erosion, as head walls, or for building up out of the flood plain, SRWs are all commonplace in today’s commercial construction. Irving, Texas, has used SRWs not only to solve erosion problems along Delaware Creek but as an aesthetic focal point of their Fritz Park and Delaware Creek Park projects. Special production color blends were devised to coordinate with local natural stone. According to Casey Tate, parks planning and construction supervisor for the city of Irving, “Citizen feedback on park improvements has been extremely positive. The SRWs have contributed an aesthetic solution to a very ugly erosion problem.” To date, in excess of 90,000 square feet of channel walls have been installed on the park projects.