Very few yards in the Northwest have level lots. Retaining walls add eye catching esthetics to any yard. Materials used to build walls include boulders, manufactured block, hand stack block, CMU block with mason stone, and masonry walls. Depending on the budget and application, natural or cultured stone products will be used. One product that will not be used is wood. We live in a wet environment and wood will succumb to wetness in a very short period of time making the structure an eyesore and compromising the structures integrity.