Basically, the risk of the extra exposed nails isn't worth the negligible moss and algae protection. http://katamari.rinoa.info/bbs/index.cgi?command=read_message26amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;msgnum=gangwonheemang.com/bbs/board.php%3Fbo_table%3Dfree%26wr_id
