have you ever heard of co polymer? It's a clear liquid of concentrated polymer plastic residue of which you can coat wood --metals and other material and will basically preserve your materials double life . On wood you can mix termacide in the liquid and when it dries it will permanately stauy on your wood for life, help from boring insects. It can bind gravel and also can help divert water from any place watter is not desired! Just google it, and you will distributors for it. Justt a thought. Aloha Al