Durable Community Fencing Improves the Property Value of Many Homes 
 

Durable Community Fencing Improves the Property Value
of Many Homes

The Evergreen Community Association (ECA) in Woodbury, MN, an eastern suburb of Minneapolis and St. Paul, was sculpted on the site of a former Christmas tree farm back in 1980, and since that time, the population has quadrupled in the City of Woodbury. In 1985 the ECA constructed a 6’ft (1.8m) cedar fence on the eastern edge to add a little privacy to the homes as the traffic increased along the bordering roadway. Now, 23 years later, the ECA was facing two major problems, deterioration of the existing fence and increase traffic noise.

Plan

The existing cedar fence had deteriorated beyond repair and was becoming an eyesore. Since the main entrance to the association was framed on either side by this fence, the association was looking for a fence option that was maintenance free and enhanced the curb appeal of their main entrance. Simply replacing the fence with a second cedar fence was considered, but the future maintenance of a wood fence was not heavily favored.

 

Through their investigation, the Association found that a mortarless concrete unit fence would be the best option for the community.

  • Durability: A system built using mortarless, stackable concrete units would have the proven performance of reinforced concrete and long term durability.
  • Cost: A lower total cost when compared to other concrete fencing options. (See Figure 1 for a cost comparison between different 8 ft (2.4 m) fencing.)
  • Aesthetics: By combining four different unit shapes, an attractive pattern was created to best fit the look and feel of the surrounding area.
  • Sound Abatement: A concrete product would provide the best sound barrier from the traffic noise coming from the four lane road that ran along the eastern border of the development. (See Figure 2 for a comparison of sound transmission between fence construction material.)

Design

The new fence was to be located in the same place as the existing wooden fence; however, this required a little creativity in design and layout. The fence height was expanded to 8 ft (2.4 m) to further reduce noise transmission. The fence needed to accommodate over a 40 ft (12.2 m) grade change, which meant the panels had to step down at both the post locations and, at times, within the panel itself.

Designers from the fence licensor worked with the ECA to come up with the preliminary design for the Fence. The fence was designed with a wind loading of 80 mph (129 Km/hr) with moderate exposure. This design allowed the 8 foot (2.4 m) tall fence to have spacing between the posts of over 16 feet (4.9 m). The designed pile footings for the fence were 2 ft (0.6 m) in diameter and 4.5 ft (1.4 m) deep, however the City required a 5 ft (1.5 m) minimum depth. The panels were designed with reinforced bond beams located at the top and bottom of the panel sections. The bond beams were constructed by using a # 4 (M# 13) reinforcing steel between two courses of block that were grouted together. Since the panel sections were 12 courses tall, this meant that eight courses for a total height of 5.3 ft (1.6 m) were dry stacked between the bond beams making the pattern easier to install. To carry the same look throughout the full panel, a single course pattern was used to build the bond beams. The design also called for flipping random blocks around to change the appearance of the fence. This ensured that both sides of the fence had the aesthetics of a random pattern.

Additionally, water management was crucial. There were specific drainage points that the City of Woodbury required to be maintained to ensure that backyards would not flood. Working with the City to identify these areas, the contractor, Sierra Exteriors, was able to construct the bottom bond beam with openings to allow any water to flow through the fence.

Build
Construction began in November which allowed the contractor to keep his crews busy during the winter months. Like any successful fence project the contractor started with marking out the proper locations for the pile footings. As the pile footings were being excavated, they encountered boulders and rocks below grade. Each rock had to be removed to maintain the proper location of the post. The pile footings were then filled with concrete and jigs were used to ensure that the vertical steel was properly positioned.

Once the footings were completed, the posts and panels of the fence were started. The fence design used the full sized panel blocks for the base. This made it easier to install the panels straight and level and simplified the installation of the reinforcing steel and 9 gauge wire stirrups through the bond beam. To finish the bond beam the cores ofthe panel blocks were filled with concrete. Because of the winter conditions, the contractor did have to protect the fresh concrete when the temperature dropped below freezing during the evenings. Temporary tents, heaters and insulated blankets were used throughout the project.

With the high visibility of the project, everybody was interested in the color of the unit and the pattern options for the fence. The manufacturer provided a beautiful three colored blend unit for the project. To add to the random pattern look of the pattern, random units were flipped backwards to create a change in the face appearance. This meant that both the City of Woodbury and the homeowners enjoyed the beautiful aesthetic color and finish of the mortarless concrete unit fence. A local building inspector from the City of Woodbury commented that, “This fence has just set the standard for the fence projects in the City and it has exceeded our expectations”. CMD

Project Contacts:
Mortarless Concrete Unit Licensor:
Allan Block
Mortarless Concrete Unit Producer: Amcon Block, St. Cloud, Minnesota
Contractor: Sierra Exteriors, St. Paul, Minnesota