When I received a request to build a retaining wall in the tropical rainforest in Arenal, Costa Rica, I thought it was unusual only based on the location. The client had a mud slide area in her 27-acre rainforest garden, but wanted a vision of two large concrete trees supporting “mystical” doors leading into an embankment.
The trees, measured six feet in diameter at the trunk area and 10 feet high, would support two doors – one of which appeared to be slightly open. The doors are 12 inches thick and made of concrete and steel armature, which was hand carved to look like an old wood and metal Celtic design; the hinges are made of a 2-1 ratio mortar mix.
The trees were formed of rebar by bending the intricate shapes by hand, and then sprayed with cement to a thickness of six inches. After the first coat of cement cured the plaster mix was sprayed on and carved to resemble native trees in the surrounding rainforest.
The trees and doors act as a retaining wall holding back a 12-feet-tall, 30-inch-wide embankment where the natural run off of rain has created a mudslide. Six artificial boulders formed of steel and concrete were created to replicate native rock in the area. The boulders were placed below the trees and doors on the sloping embankment, staggered to slow erosion of the embankment.
The project was completed in 14 days with the help of the client’s grounds keepers. The client’s vision of her mystical rainforest garden has made the traditional retaining walls a thing of the past. Check out pictures of the finished product on the Pro Forum.