Wood/Mulch, Wood based materials, including engineered wood fiber (EWF) mulch, are the most commonly used playground surfacing materials because they are easily accessible, easy to install and have a much lower initial cost than other playground surfacing options. EWF mulch is composed of wood that's been ground to a fibrous consistency and is sometimes manufactured to be “knit” together in order to form. Engineered wood fiber mulch (EWF) is an economical playground surfacing, it's easy to install, and it meets all accessibility guidelines. EWF (engineered wood fiber) playground mulch is made by chipping and shredding various soft and/or hardwoods into chips that meet certain. Premium Engineered Wood Fiber Playground Mulch Engineered Wood Fiber (EWF) is the most common type of playground safety surfacing. This wood fiber playground mulch is designed and tested to be a superior product with long-term, trouble-free performance: Superior raw material.